JP6503763B2 - Far electromagnetic field estimation device - Google Patents

Description

The present invention measures an electromagnetic field generated by an electromagnetic wave radiation source such as an electronic device in the vicinity of the radiation source, and estimates the electromagnetic field at a distant observation point farther from the radiation source based on the measured electromagnetic field. Remote electromagnetic field estimation apparatus.

  Generally, in the test to measure the radiation interference emitted from the electronic equipment etc., the radiation is mainly radiated at 10 m or 3 m away from the radiation source of the radiation interference according to the internationally defined test conditions and test method. Interference measurements are taken. In addition, a test for measuring a radiation disturbance in a frequency band of 30 MHz to 1 GHz is generally performed by arranging a specimen as a radiation source above or above a ground plane (metal floor).

  Also, in general, tests to measure radiation disturbances are conducted in an anechoic chamber that satisfies the compatibility of an open site or an internationally defined site. The anechoic chamber is configured by sticking a radio wave absorber on the wall surface of the shield room. In the anechoic chamber, the size and shape of the shield room and the type of the radio wave absorber are selected according to the purpose of use and the frequency of the electromagnetic wave used. The main anechoic chamber is about 20 to 30 m in length, about 10 to 20 m in width, about 10 to 20 m in height, and about 7 to 11 m in length, about 4 to 7 m in width. There is a 3 m radio anechoic chamber about 5 to 7 m in height. These are used according to the distance required for the test which measures a radiation interference wave.

  The anechoic chamber requires relatively large length, width and height as mentioned above, and the building facility becomes large scale, and the total investment and maintenance operation cost to the building facility and various necessary facilities become large. have.

  Therefore, there is a need for a small-scale device capable of measuring radiation interference in a smaller space. In response to this requirement, a device for measuring the near-field electromagnetic field for printed circuit boards etc., a device for measuring the near-field electromagnetic field, and the measured near-field electromagnetic field using Love's equivalence theorem etc. A method has been proposed to estimate the far electromagnetic field.

  For example, in Patent Document 1, a virtual rectangular solid or cylinder is set so as to surround an object to be measured, and an electromagnetic field is measured to scan the surface of the rectangular solid or cylinder, and the measured electromagnetic field is used. A method is described for estimating the electromagnetic field at a position further from the object to be measured. Further, Patent Document 1 describes that only one other five surfaces may be scanned with one surface of a virtual rectangular solid as a ground surface.

Unexamined-Japanese-Patent No. 2004-69372

Japanese Patent Application No. 2013-166651

  According to the method described in Patent Document 1, a virtual rectangular solid or cylinder is set so as to surround the object to be measured without considering the ground surface, and the surface of the rectangular solid or cylindrical is scanned or virtual Only one other surface is scanned with one surface of the rectangular parallelepiped as the ground surface. That is, in this method, the influence of the ground plane is not considered. Therefore, when this method is applied to a test conducted under the condition that the DUT is placed on the ground plane as described above, the estimated electromagnetic field is actually measured by the influence of the ground plane. It can easily be inferred that the

In order to solve this problem, the inventors invented a method for accurately estimating the far electromagnetic field without being affected by the ground plane, and filed a patent application (Patent Document 2). This patent document 2 does not include the lower surface of the radiation source, and the equivalence theorem in the measurement of the amplitude and phase of the near electromagnetic field tangent component of the six sides of a virtual rectangular parallelepiped set so as to surround the radiation source. In the measurement plane set by the four planes perpendicular to the ground plane and the upper plane, the mirror plane formed by the ground plane is given, and the rectangular parallelepiped plane formed via the ground plane is A method is described in which the electromagnetic field tangential component in the mirror image measurement plane is given amplitude and phase according to the image principle, and the electromagnetic field of the distant observation point is estimated according to the equivalence theorem.
However, in the method described in Patent Document 2, since it is necessary to measure the near electromagnetic field on the upper surface of the object to be measured, further improvement is desired from the viewpoint of cost reduction and efficiency of measurement.

  The present invention has been made in view of such problems, and an object thereof is based on an electromagnetic field measured in the vicinity under a condition where a radiation source of the electromagnetic wave is not enclosed under the condition where a ground plane exists. An object of the present invention is to provide a far electromagnetic field estimation apparatus capable of easily and accurately estimating the electromagnetic field at an observation point farther from the radiation source.

  A far electromagnetic field estimation apparatus according to the present invention determines at least one of an electric field and a magnetic field formed at a distant observation point of a distance r from a test object which is a radiation source of an electromagnetic wave disposed above a ground plane. It is an apparatus. The far electromagnetic field estimation apparatus includes a near electromagnetic field measurement apparatus and an arithmetic processing unit.

  The apparatus for measuring the near electromagnetic field comprises a probe for detecting at least one of an electric field and a magnetic field, an antenna for referring to the phase of the electric field and the magnetic field, a position control mechanism capable of changing the relative position of the probe with respect to the specimen, And a control unit configured to control measurement of at least one of an electric field and a magnetic field using the antenna and the position control mechanism.

The control unit is
When the y-axis is in the height direction above the ground plane, the z-axis is in the direction of the observation point, and the x-axis is in the direction orthogonal to the y-axis and z-axis based on the position of the specimen assuming a forward measurement surface at a position away forward a distance + z (distance z is sufficiently smaller than the distance r), the maximum height h from the ground plane of center height h _EUT and far observation point from the ground plane of the specimen The height from the ground plane where the straight line connecting _Rx intersects the front measurement plane is determined from the equation (1) as the reference height h _ref ,
Assuming a backward measurement plane at a position separated by an equal distance -z backward as well as forward from the specimen, a straight line connecting the reference height h _ref in the backward measurement plane and the maximum height h _Rx of the distant observation point is forward Based on the height at which the measurement surface intersects, the measured height h _meas is obtained by equation (2),
The measurement height h _meas or less on the measurement plane formed perpendicular to the ground plane at a distance of ± z at the front and rear and ± x at the left and right (distance x is sufficiently smaller than the distance r) Provide multiple measurement points on the measuring plane formed perpendicular to the ground plane at an equal distance of z = ± x, or on the measuring plane formed perpendicular to the ground plane at an equal distance of z The first operation,
Using the probe, antenna, and position control mechanism, it is a component of the measuring direction of a plurality of measuring point electric fields that are tangential components of the measuring surface of the electric field at a plurality of measuring points and a component of the measuring direction of a magnetic field at a plurality of measuring points A second operation of measuring at least one of the plurality of measurement point magnetic fields is performed.

The arithmetic processing unit
A plurality of mirror image points having a positional relationship of plane symmetry with a plurality of measurement points with respect to a ground plane are set on a mirror image measurement plane having a positional relationship of plane symmetry with the measurement plane with the ground plane as a center. At least one of a plurality of mirror point electric fields and a plurality of mirror image points which are tangential components of the mirror image measurement surface of the plurality of mirror image points based on at least one of the plurality of measurement point electric fields and the plurality of measurement point magnetic fields A first calculation process for calculating at least one of a plurality of mirror image point magnetic fields that are components of the tangential direction of the mirror image measurement surface of the magnetic field;
Based on at least one of a plurality of measurement point electric fields and a plurality of measurement point magnetic fields measured in the second operation, and a plurality of mirror image electric fields and a plurality of mirror image magnetic fields calculated in the first arithmetic processing And performing a second arithmetic process of calculating at least one of an electric field and a magnetic field at the distant observation point.

  Further, the plurality of measurement points may be arranged in two directions crossing each other. In this case, in each of the two directions, the distance on the measurement surface between two adjacent measurement points may be half or less of the wavelength of the electromagnetic wave.

  In addition, an antenna that refers to the phase is provided outside the measurement surface, and is arranged so that the distance and the positional relationship with the specimen are always constant in synchronization with the position of the radiation source.

  Further, in the far electromagnetic field estimation apparatus of the present invention, the plurality of measurement point electric fields, the plurality of measurement point magnetic fields, the plurality of mirror point electric fields and the plurality of mirror point magnetic fields are respectively a horizontal component parallel to the ground plane and the ground plane. And vertical components may be included. In this case, the horizontal components of the plurality of mirror point electric fields are equal in phase but opposite in phase to the horizontal components of the corresponding measurement point electric fields. The vertical components of the plurality of mirror point electric fields are equal in amplitude and phase to the vertical components of the corresponding measurement point electric fields, respectively. The horizontal components of the plurality of mirror point magnetic fields are equal in amplitude and phase to the horizontal components of the corresponding measurement point magnetic fields. The vertical components of the plurality of mirror image point magnetic fields are equal in amplitude but opposite in phase to the vertical components of the corresponding measurement point magnetic fields.

  Further, in the far electromagnetic field estimation apparatus of the present invention, the test object, the probe, the position control mechanism and the antenna may be disposed in a radio wave anechoic chamber having a metal floor surface constituting a ground plane.

  In the far electromagnetic field estimation apparatus of the present invention, the probe may have an electric field detection unit that outputs a signal according to the electric field, and a magnetic field detection unit that outputs a signal according to the magnetic field. In addition, the probe detects a horizontal component parallel to the ground plane and a vertical component perpendicular to the ground plane at a plurality of measurement point electric fields and a plurality of measurement point magnetic fields. May be included. The electric field detection unit includes an electric field antenna unit that generates a differential signal according to the electric field, two electric field output ports that output a differential signal generated by the electric field antenna unit, and an electric field that shields part of the electric field antenna unit. It may include a shield part. The magnetic field detection unit includes a magnetic field antenna unit that generates a differential signal according to the magnetic field, two magnetic field output ports that output a differential signal generated by the magnetic field antenna unit, and a magnetic field that shields part of the magnetic field antenna unit. It may include a shield part.

  In addition, first correction information for correcting the amplitude and phase of the output signal of the electric field detection unit to values corresponding to the amplitude and phase of the electric field actually received by the electric field detection unit, and the output signal of the magnetic field detection unit Second correction information for correcting the amplitude and phase to values corresponding to the amplitude and phase of the magnetic field actually received by the magnetic field detection unit may be obtained in advance. Then, the arithmetic processing unit may calculate the plurality of measurement point electric fields and the plurality of measurement point magnetic fields based on the first and second correction information. In this case, in the first arithmetic processing, the plurality of mirror image electric fields and the plurality of mirror image magnetic fields are calculated based on the plurality of measurement point electric fields and the plurality of measurement point magnetic fields obtained by the first and second correction information. You may In the second arithmetic processing, the electric field at the distant observation point and the electric field at the distant observation point are obtained based on the plural measurement point electric fields, the plural measurement point magnetic fields, the plural mirror point electric fields and the plural mirror point magnetic fields At least one of the magnetic fields may be calculated.

  In addition, in order to correct the electric field of the distant observation point to a value measured by the actual receiver, third correction information for correcting the receiving antenna characteristic and fourth correction information for correcting the path characteristic are obtained in advance. And may be converted to a voltage measured at the receiver based on the third and fourth correction information.

  For the third correction information, in free space, from the reference radiation source, place the receiving antenna at the distant observation point and use the free space antenna factor to obtain the transmission loss characteristics, and then only the reference radiation source Alternatively, the electric field strength at the distant observation point may be obtained, and the electric field strength and the transmission loss may be subtracted.

  In the third correction information, the reference radiation source is disposed at an arbitrary height from the ground plane, the receiving antenna is disposed at a distant observation point, and the transmission loss is determined. Alternatively, the electric field strength at the distant observation point may be determined, and the transmission loss may be subtracted from the electric field strength.

In the far-field electromagnetic field estimation apparatus according to the present invention, for example, on the measurement surface which does not include the upper surface formed vertically to the ground plane with a distance of ± z back and forth and ± x left and right at the measurement height h _meas or less. A plurality of measurement points are set to measure at least one of a plurality of measurement point electric fields and a plurality of measurement point magnetic fields, and a plurality of mirror image points are set on a mirror image measurement surface to measure a plurality of measurement point electric fields At least one of the plurality of mirror point electric fields and the plurality of mirror point magnetic fields is calculated based on at least one of the plurality of measurement point magnetic fields. Then, the electric field and the magnetic field at the distant observation point are based on at least one of the plurality of measured point electric fields and the plurality of measurement point magnetic fields and at least one of the calculated plurality of mirror point electric fields and the plurality of mirror point magnetic fields. Calculate at least one of Thereby, according to the present invention, the electromagnetic field at the distant observation point is measured based on the electromagnetic field measured on the measurement surface not including the upper surface formed perpendicular to the ground plane in the vicinity of the specimen of the electromagnetic wave. Can be accurately estimated. Further, according to the present invention, since measurement is performed on a measurement surface not including the upper surface, cost reduction of the far electromagnetic field estimation apparatus and high efficiency of measurement can be achieved.

It is a perspective view which shows the example of arrangement | positioning of a far electromagnetic field estimation apparatus. It is a side view of a far electromagnetic field estimation device for showing a relation of a neighborhood measurement point, a mirror image point, and a distant observation point. It is an explanatory view which is provided for explanation of formulas (1) and (2) which determine measurement surface height h _meas . FIG. 7 is an explanatory view for explaining a plurality of measurement points and a plurality of mirror image points. FIG. 7 is an explanatory diagram for describing a method of calculating a mirror image electric field and a mirror image magnetic field. FIG. 7 is an explanatory diagram for describing an operation of the near electromagnetic field measurement apparatus. It is an operation | movement flowchart of a near electromagnetic field measuring apparatus. It is a perspective view which shows an example of an electric field detection part. It is a perspective view which shows an example of a magnetic field detection part. It is a front view and a side view showing an example of a crossing type electric field probe. It is a front view and a side view showing an example of a crossing type magnetic field probe. It is a related figure showing the relation of an electric field and a magnetic field detection part, a phase reference point antenna, a preamplifier, and a receiver. It is a schematic diagram showing an example of an oscilloscope and an architecture of vector signal analysis software. FIG. 6 is an explanatory diagram for describing a method of measuring an electromagnetic field probe coefficient. It is a characteristic view showing an example of an electric field probe coefficient. It is a characteristic view showing an example of a magnetic field probe coefficient. It is an explanatory view which serves to explain a precondition for calculating an antenna coefficient. FIG. 6 is an explanatory diagram provided for describing calculation of an antenna coefficient in free space. It is a characteristic view which shows an example of the antenna coefficient calculated based on FIG. FIG. 7 is an explanatory diagram provided for describing calculation of an antenna coefficient in consideration of a ground plane. It is a block diagram showing composition of a computer in an embodiment of the present invention. It is a processing flow figure of the arithmetic processing part of the embodiment of the present invention. It is a circuit diagram showing a simulated noise generator used to verify the validity of the present invention. It is an explanatory view which serves to explain an experiment carried out to verify the validity of the present invention. FIG. 10 is an explanatory view provided for describing a comparative experiment according to Patent Document 2. It is a characteristic view showing the 50 MHz height pattern in 3 m of distances. It is a characteristic view showing the height pattern of 100 MHz in distance 3 m. It is a characteristic view showing a 300 MHz height pattern in 3 m of distances. It is a characteristic view showing the 500 MHz height pattern in 3 m of distances. It is a characteristic view showing the 800 MHz height pattern in 3 m of distances. It is a characteristic view showing a 50 MHz height pattern at a distance of 10 m. It is a characteristic view which shows the height pattern of 100 MHz in 10 m of distances. It is a characteristic view showing a 300 MHz height pattern at a distance of 10 m. It is a characteristic view which shows the height pattern of 500 MHz in 10 m of distances. It is a characteristic view showing the 800 MHz height pattern in 10 m of distances. It is a measurement systematic diagram which shows the measurement system in the actual distance. It is a characteristic view showing the frequency characteristic of the maximum reception voltage in distance 3 m. It is a characteristic view showing the frequency characteristic of the maximum reception voltage in distance 10m. It is the schematic which shows the circuit board which imitated the real machine used in order to verify the validity of the present invention. It is an explanatory view which is provided for measurement explanation of a circuit board which imitated an actual machine implemented in order to verify validity of the present invention. It is a characteristic view showing distance 3 m and the frequency characteristic of the maximum reception voltage in horizontal polarization. It is a characteristic view showing distance 3 m and the frequency characteristic of the maximum reception voltage in vertical polarization. It is a characteristic view which shows the distance 10 m and the frequency characteristic of the maximum reception voltage in horizontal polarization. It is a characteristic view showing distance 10 m and the frequency characteristic of the maximum reception voltage in vertical polarization. It is an explanatory view which is provided for measurement explanation of a game machine carried out to verify validity of the present invention. It is a measurement systematic diagram which shows the measurement system in the actual distance. It is a characteristic view showing the comparison examination frequency in the radiation interference wave of a game machine. It is a characteristic view showing distribution characteristic of reception voltage in 373 MHz, distance 3 m, and horizontal polarization. It is a characteristic view showing distribution characteristic of reception voltage in 373 MHz, distance 3 m, vertical polarization. It is a characteristic view which shows the distribution characteristic of the receiving voltage in 590 MHz, distance 3 m, and horizontal polarization. It is a characteristic view which shows distribution characteristic of the receiving voltage in 590 MHz, distance 3 m, and a vertical polarization. It is a characteristic view which shows the distribution characteristic of the receiving voltage in 786 MHz, distance 3 m, and horizontal polarization. It is a characteristic view showing distribution characteristics of received voltage in 786 MHz, distance 3 m, vertical polarization.

First Embodiment
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  The far electromagnetic field estimation apparatus according to the present embodiment includes an apparatus for performing measurement of the near electromagnetic field, calculation of the near electromagnetic field, and an arithmetic processing unit for estimating the far electromagnetic field. As an example, FIG. 1 shows a near electromagnetic field measurement apparatus that measures a plane not including the upper surface of a rectangular parallelepiped formed perpendicular to the ground plane 1. The device for measuring the near electromagnetic field includes a probe 8 for detecting at least one of an electric field and a magnetic field, a small antenna (phase reference point antenna) 11 for referring to the phase of the electric field and the magnetic field, and a relative relationship of the probe 8 with respect to the specimen 2 Control that performs measurement control of at least one of an electric field and a magnetic field using a position control mechanism (specifically, the scanner 9 and the rotating table 10) which can change the position, the probe 8, the small antenna 11, and the position control mechanisms 9 and 10. A unit (specifically, a scanning controller 15 and a computer 17 described later) is provided. Here, the scanner 9 and the rotating table 10 and the rotator 12 are connected to the scanning controller 15 by a control cable 16. Also, the probe 8 and the phase reference point antenna 11 are connected to the receiver 13 via the preamplifier 14. Further, communication between the control unit of the scanning controller 15 and the receiver 13, and a measurement control / operation processing computer 17 for executing measurement control of the entire system, calculation processing of electric field or magnetic field, and far electromagnetic field estimation There is. In the present embodiment, the control unit and the arithmetic processing unit corresponding to the claims are realized by the computer 17 and its peripheral devices (13, 14, 15). In the present embodiment, at least the specimen 2, the phase reference point antenna 11, and the position control mechanisms 9 and 10 are disposed in a radio wave anechoic chamber having a metal floor surface that constitutes the ground plane 1.

  In the measurement of the near electromagnetic field in the plane not including the upper face of the rectangular parallelepiped formed perpendicular to the ground plane 1 shown in FIG. 1, first, the scanning controller connected to the computer 17 by the communication cable 18 The control unit 15 controls the probe 8 mounted on the scanner 9 to measure at least one of the electric field and the magnetic field at a plurality of measurement points on one surface. Next, the rotation table 10 is controlled by the scanning controller 15 to rotate the specimen 2 every 90 degrees, and the rotator 12 is controlled by the scanning controller 15 to rotate the phase reference point antenna 11 to the rotation table 10. By rotating the optical sensor in synchronization with the angle of 90 degrees, at least one of the electric field and the magnetic field at a plurality of measurement points on another surface can be obtained.

  The preamplifier 14 amplifies each of two signals constituting a differential signal output from the electric field detection unit or the magnetic field detection unit of the electromagnetic field probe 8 and sends the amplified signal to the receiver 13. The preamplifier 14 amplifies the output signal of the reference point antenna 11 and sends it to the receiver 13. The receiver 13 generates a plurality of measurement data corresponding to the plurality of received signals. A plurality of measurement data are sent from the receiver 13 to the computer 17.

  Next, with reference to FIG. 2, a method of estimating a far electromagnetic field by the far electromagnetic field estimation device will be described. In the far electromagnetic field estimation apparatus according to the present embodiment, as shown in FIG. 2, the distance from the test object 2 to the test object 2 of the electromagnetic wave disposed in one of the two spaces partitioned by the ground plane 1 At least one of an electric field and a magnetic field at a distant observation point 3 separated by r is determined.

Here, the ground plane 1 is an equipotential surface, and is realized by, for example, a metal floor surface. The two spaces divided by the ground plane 1 refer to the space above the ground plane 1 and the lower side of the ground plane 1 when the ground plane 1 is positioned horizontally as shown in FIG. It is a space. In FIG. 2, the specimen 2 is disposed in the space above the ground plane 1. The specimen 2 is, for example, an electronic device that generates an electromagnetic wave. Such a situation is, for example, a situation in which the specimen 2 is disposed in a radio anechoic chamber having a metal floor surface that constitutes the ground plane 1. In FIG. 2, the height of the observation point 3 with respect to the ground plane 1 is represented by a symbol h _Rx .

  The far electromagnetic field estimation apparatus according to the present embodiment includes the following first and second operations and first and second arithmetic processing.

供試体２から前方と同様に後方に等距離−ｚで離れた位置における後方の測定面４を想定し、後方の測定面４における基準高さｈ_ｒｅｆと遠方観測点３の最大高さｈ_Ｒｘを結ぶ直線が、前方測定面４と交差する高さを基準に測定高さｈ_ｍｅａｓを（２）式により求め、

測定高さｈ_ｍｅａｓ以下で前後が±ｚ及び左右が±ｘ（距離ｘは距離ｒより十分小さい）の距離でグランドプレーン１に対して垂直に形成される上方の面を含まない測定面４に、複数の測定点５を設ける第１の動作と、
プローブ８、位置参照点アンテナ１１、位置制御機構９、１０を用いて、複数の測定点５における電界の測定面の接線方向の成分である複数の測定点電界と、複数の測定点５における磁界の測定面の接線方向の成分である複数の測定点磁界の少なくとも一方を測定する第２の動作を実行する。 The control unit is
As shown in FIG. 2, based on the position of the specimen 2, the y axis is orthogonal to the height direction above the ground plane, the z axis to the observation point direction, and the x axis to the y axis and the z axis Assuming the forward measurement plane 4 at a position separated by a distance + z (the distance z is sufficiently smaller than the distance r) forward from the specimen 2 when assuming the direction, center height h from the ground plane 1 of the specimen 2 _The height from the ground plane 1 where the straight line connecting the ground plane 1 to the maximum height h _Rx from the _EUT and the distant observation point 3 intersects the measurement plane 4 is determined by the equation (1) as the reference height h _ref

Assuming the rear measurement surface 4 at a position separated by an equal distance -z to the rear similarly to the front from the specimen 2, the reference height h _ref at the rear measurement surface 4 and the maximum height h _Rx of the distant observation point 3 Based on the height at which the straight line connecting the points intersects the front measurement surface 4, the measured height h _meas is obtained by the equation (2),

Measurement surface 4 not including the upper surface formed perpendicular to ground plane 1 at a distance of ± z before and after and ± x at the left and right (distance x is sufficiently smaller than distance r) at measurement height h _meas or less , A first operation of providing a plurality of measurement points 5;
Using the probe 8, the position reference point antenna 11, and the position control mechanisms 9 and 10, a plurality of measurement point electric fields that are components of the tangential direction of the measurement surface of the electric field at the plurality of measurement points 5 and a magnetic field at the plurality of measurement points 5 Performing a second operation of measuring at least one of the plurality of measurement point magnetic fields that are components of the measurement surface in the tangential direction of

For example, the measurement surface 4 does not include the upper surface formed perpendicular to the ground plane 1 at the measurement height h _meas or less with the distance between the back and forth ± z and the distance between the left and right ± x Assuming that the measuring surface 4 does not include the upper surface formed perpendicular to the ground plane 1 with an equal distance of ± z = ± x on the left and right sides, the sample 2 is rotated by 90 degrees by the rotation table 10, At the same time, by rotating the small antenna 11, which is a phase reference point, every 90 degrees by the rotator 12, a plurality of measurement point electric fields and a plurality of measurement point magnetic fields can be obtained on the entire surface of the measurement surface 4 not including the upper surface. . Even if the measurement surface 4 is an equidistant radius and does not include the upper surface formed perpendicular to the ground plane 1 with a distance of z, it is rotated at an arbitrary angle interval using the rotation table 10 to perform position control When the scanner 9 is scanned up and down at the center of the specimen 2, a plurality of measurement point electric fields and a plurality of measurement point magnetic fields can be obtained on the entire surface of the measurement surface 4 not including the upper surface.

The arithmetic processing unit
As shown in FIG. 2, it has a positional relationship of plane symmetry with a plurality of measurement points 5 around the ground plane 1 on the mirror image measurement plane 6 which has a positional relationship of plane symmetry with the measurement surface 4 with the ground plane 1 as a center. The plurality of mirror image points 7 are set, and the tangential direction of the mirror image measurement surface 6 of the plurality of mirror image points 7 based on at least one of the plurality of measurement point electric fields and the plurality of measurement point magnetic fields measured in the second operation. A first calculation process for calculating at least one of a plurality of mirror-image electric fields that are components of the image and a plurality of mirror-image magnetic fields that are components of the tangential direction of the mirror image measurement surface 6 of the magnetic field at the plurality of mirror images 7;
Based on at least one of a plurality of measurement point electric fields and a plurality of measurement point magnetic fields measured in the second operation, and a plurality of mirror image electric fields and a plurality of mirror image magnetic fields calculated in the first arithmetic processing And a second arithmetic process of calculating at least one of an electric field and a magnetic field at the distant observation point 3.

On the other hand, the far electromagnetic field estimation method according to the present embodiment includes the following first to fourth procedures. In the first procedure, multiple measurement points are set on the measurement surface that does not include the upper surface formed perpendicular to the ground plane with a distance of ± z back and forth and ± x on the left and right with a measurement height h _meas or more Do.

  In the second procedure, a plurality of measurement point electric fields that are components of the measurement direction of the electric field at a plurality of measurement points in the tangential direction and a plurality of measurement point magnetic fields that are components of the measurement direction of the magnetic field at a plurality of measurement points. Measure at least one of the

  In the third procedure, on the mirror image measurement plane that has a positional relationship of plane symmetry with the measurement plane centering on the ground plane, multiple mirror image points that have a positional relationship of plane symmetry with multiple measurement points around the ground plane are set And at least one of the plurality of measuring point electric fields and the plurality of measuring point magnetic fields measured in the second procedure, the plurality of mirror point electric fields being tangential components of the mirror surface of the plurality of mirror points. And at least one of a plurality of mirror image point magnetic fields that are tangential components of the mirror image measurement surface of the magnetic field at the plurality of mirror image points.

  In the fourth procedure, at least one of the plurality of measurement point electric fields and the plurality of measurement point magnetic fields measured in the second procedure and the plurality of mirror image electric fields and the plurality of mirror image magnetic fields calculated in the third procedure Based on at least one, at least one of the electric field and the magnetic field of the distant observation point is calculated.

Next, with reference to FIG. 3, the basis for determining the measurement height h _meas will be described. In the far electromagnetic field estimation of the present invention, the principle of Hygens Fresnel is applied. In the Haigens-Fresnel principle, the electromagnetic field in any plane away from any wave front can be considered as a second-order elementary wave that generates a spherical wave, and is mathematically processed by the equivalence theorem proposed by Schelkunoff be able to. Here, in the far-field electromagnetic field estimation apparatus of the present invention, for example, assuming that the surface not including the upper surface formed perpendicular to the ground plane is the measurement surface 4, a second-order elementary element wave in the upper surface The height h _meas of the measurement surface 4 needs to be determined so as to compensate for the electromagnetic energy of At least, as shown in FIG. 3, it is necessary to consider the path of the electromagnetic wave propagating from the specimen 2 to the observation point 3, and the central height h _{EUT of the} specimen 2 and the maximum height h _Rx of the distant observation point 3 It is necessary to include a second-order elementary wave equal to or greater than the height h _ref at which the connecting straight line intersects with the front measurement surface 4 (here, the reference height). Further, since the secondary originally wave to the rear of the measuring surface 4 also greatly affected, it is necessary to apply a reference height h _ref backward measuring surface 4, a reference height h _ref in the rear measurement surface 4 far A straight line connecting the maximum height h _Rx of the observation point 3 crosses the front measurement surface 4 as a measurement height h _meas , and the measurement range is below this measurement height h _meas , It is possible to compensate for the electromagnetic energy of the secondary element wave in the upper surface.

The first arithmetic processing and the second arithmetic processing are executed based on the measured height h _meas determined in this way, and mathematical processing is performed according to the equivalence theorem proposed by Love and Schelkunoff to calculate the far electromagnetic field. You can ask for For example, when the electromagnetic current density distribution is given at the measurement point 5 shown in FIG. 2, the electromagnetic field may be obtained directly, but can be obtained through the vector potential function shown in the equations (3) and (4). One of the great advantages is that the Cartesian coordinate components of the vector potential functions A, F are reduced to scalar wave equations and solutions are relatively easy to find. The solutions using Fourier transform for the equivalent electromagnetic current densities J and M are equations (5) and (6).

G is a green function, and ▽ G, GG / r, and GG / r ² are expressed by equation (7). Here, η is an intrinsic impedance, k is 2π / λ, λ is the wavelength of the electromagnetic wave, r in vector notation is a unit direction vector directed to the observation point.

Finally, the first and second terms of the equation (3) are expressed by the equation (8).

Subsequently, the third term of the equation (3) is expressed by the equation (9).

Assuming that the measurement plane 4 of the near field is a plane according to the equations (8) and (9), the plane is divided into lattices mn, and the volume integral is expressed by the area, resulting in the equation (10) to calculate the electric field be able to. The equivalent electromagnetic current densities J _mn and M _mn are represented by the measured electromagnetic field (tangent component) by approximation by equation (11). Here, ds _mn represents a minute area on the surface S.

On the other hand, the magnetic field can be calculated by equation (12).

In equations (10) and (12), if the distribution of the tangential component of the surface S of the electromagnetic field on the surface S is correctly understood, it is used as a wave source, and observation of an arbitrary position is made from the uniqueness of the solution of the electromagnetic field. It means that the electromagnetic field at the point can be determined. The equivalent electromagnetic current density J _mn and M _mn on the surface S is expressed by the solution using the Fourier transform shown in the equations (5) and (6), so the observation point at any position is In order to accurately determine the electromagnetic field in, the distance between the measurement points 5 for measuring the tangential component of the surface S of the electromagnetic field on the surface S is set to λ / 2 or less according to the sampling theorem which is the property of Fourier transform There is a need.

  In the present embodiment, the surface formed by combining the measurement surface 4 and the mirror image measurement surface 6 corresponds to the surface S in the above description. The plurality of measuring point electric fields, the plurality of measuring point magnetic fields, the plurality of mirror point electric fields, and the plurality of mirror point magnetic fields correspond to tangential components of the surface S of the electromagnetic field on the surface S.

First, using Equation (11), based on the plurality of measurement point electric fields, the plurality of measurement point magnetic fields, the plurality of mirror point electric fields and the plurality of mirror point magnetic fields, equivalent electromagnetics on the measurement surface 4 and the mirror measurement surface 6 The distribution of the flow density J _mn and M _mn is determined. Furthermore, the far electromagnetic field at the observation point 3 is calculated using the equations (10) and (12).

Next, with reference to FIGS. 4 and 5, a plurality of measurement points and a plurality of mirror image points in the present embodiment will be described in detail. As shown in FIG. 4, for example, on a measurement surface 4 which does not include the upper surface of the rectangular surface formed perpendicular to the ground plane 1, the plurality of measurement points 5 are arranged in two intersecting directions It is arranged. Specifically, in the present embodiment, each of the four surfaces constituting the measurement surface 4 is divided into a plurality of regions in a grid shape. The plurality of measurement points 5 are respectively disposed at predetermined positions on the outer edge or inside of the plurality of regions. The predetermined position may be, for example, the center of the area or one of four corners of the outer edge of the area. The area of one region corresponds to ds _mn of equations (10) and (12).

In the equations (10) and (12) in which the measurement surface 4 is divided into grids mn and the volume integral is expressed by the area, the left and right upper and lower ends and the upper and lower ends of the measurement surface when arbitrary sampling intervals are used. There is a difference in the area ds _mn of the part, which affects the calculation of the radiation field. For this reason, the grid points are fixed at the left and right upper end sides and the upper end portion of the measurement surface, and the area of the part outside the grid points is not included in the calculation. Therefore, it is 1/2 of ds _mn at the left and right upper end sides, 1/4 of ds _mn at the upper end, and 3/2 of ds _mn at the lower end, and 3/4 of ds _mn at the lower end.

  In the case where the wavelength of the electromagnetic wave to be measured has a range, the interval between the lattices m (= Δx) and n (= Δy) can be determined based on the lower limit value of the wavelength of the electromagnetic wave. For example, when the upper limit value of the frequency of the electromagnetic wave is 1 GHz, the lower limit value of the wavelength of the electromagnetic wave is 30 cm. In this case, m (= Δx) and n (= Δy) are 15 cm or less, preferably 10 cm or less. That is, it may be 1/2 or less of the wavelength (lower limit value) of the electromagnetic wave.

  Next, with reference to FIG. 5, a method of calculating the mirror point electric field and the mirror point magnetic field will be described. First, with reference to FIG. 5 (a), a method of calculating the mirror measurement point electric field will be described. Here, it is assumed that the plurality of measurement point electric fields include a horizontal component E1 parallel to the ground plane 1 and a vertical component E2 perpendicular to the ground plane 1, respectively. In this case, the plurality of mirror measurement point electric fields also include a horizontal component E3 parallel to the ground plane 1 and a vertical component E4 perpendicular to the ground plane 1, respectively. The horizontal component E3 and the vertical component E4 of the plurality of mirror image measurement point electric fields are given to satisfy the boundary conditions of the ground plane 1 as follows. That is, the horizontal components E3 of the plurality of mirror image measuring point electric fields are equal in phase but opposite in phase to the horizontal component E1 of the corresponding measuring point electric field. The vertical components E4 of the plurality of mirror image measurement point electric fields are equal in amplitude and phase to the vertical components E2 of the corresponding measurement point electric fields. FIG. 5A shows the horizontal component E1 and vertical component E2 of one measurement point electric field, and the horizontal component E3 and vertical component E4 of one mirror image measurement point electric field corresponding thereto.

  Next, with reference to FIG. 5B, a method of calculating the mirror image measurement point magnetic field will be described. Here, the plurality of measurement point magnetic fields are assumed to include a horizontal component H1 parallel to the ground plane 1 and a vertical component H2 perpendicular to the ground plane 1, respectively. In this case, the plurality of mirror measurement point magnetic fields also include a horizontal component H3 parallel to the ground plane 1 and a vertical component H4 perpendicular to the ground plane 1, respectively. The horizontal component H3 and the vertical component H4 of the plurality of mirror image measurement point magnetic fields are given to satisfy the boundary conditions of the ground plane 1 as follows. That is, the horizontal components H3 of the plurality of mirror image measurement point magnetic fields have the same amplitude and phase as the horizontal components H1 of the corresponding measurement point magnetic fields. The vertical components H4 of the plurality of mirror image measurement point magnetic fields are equal in amplitude but opposite in phase to the vertical components H2 of the corresponding measurement point magnetic field. FIG. 5B shows the horizontal component H1 and the vertical component H2 of one measurement point magnetic field, and the horizontal component H3 and the vertical component H4 of one mirror image measurement point magnetic field corresponding thereto.

  The outline of the operation of the near electromagnetic field measurement apparatus when measuring at least one of the measurement point electric field and the measurement point magnetic field at the plurality of measurement points 5 using the near electromagnetic field measurement apparatus will be described with reference to FIGS. .

First, in consideration of the size of the specimen 2, the receiving sensitivity of the probe 8, and the spacing between the grids m and n, the measurement heights h _meas (= y _max ) and h _min (= y _min ) and ± Determine the dimensions of the x, ± z measurement area. In the initial state, in step S01, the position of the specimen 2 is set as the origin ((0, h _EUT , 0) in FIG. 6) and probed to the center position ((0, h _EUT , + z) in FIG. Move 8 to determine the coordinates of the space. Then, as shown in FIG. 6, the probe 8 is moved to the A position which is the measurement start point (the position of (−x, h _min , + z in FIG. 6) in step S02, and the measurement point electric field at the start point The measurement point magnetic field is measured in step S03. Next, after the measurement of the start point is completed, the probe 8 is moved by Δx in the direction along the carriage 19 in step S04, and the measurement point electric field or the measurement point magnetic field is measured in step S05. This operation is repeated until (+ x, h _min , + z), and after the measurement at h _min (= y _min ) is completed, the carriage 19 is moved along the stay 20 by Δy to measure the height h _min + Δy at the measurement point A certain (+ x, h _min + Δy, + z) measurement point electric field or measurement point magnetic field is measured. These series of operations are performed up to the B position of the end point of height h _meas (= y _max ), and the measurement of the measurement point electric field or measurement point magnetic field at a plurality of measurement points of the first measurement surface is completed in step S06. Do.

  Next, in step S07, the position of the rotary table 10 is rotated from the position of θ = 0 deg to the position of θ = 90 deg, and from the B position of the measurement start point of the second surface to the A position of the end point Steps S02 to S06 are carried out according to which the measurement point electric field or measurement point magnetic field at a plurality of measurement points on the second measurement surface is measured. In this manner, by performing steps S02 to S07 up to the fourth surface, a plurality of measurement point electric fields or a plurality of measurement point magnetic fields in the measurement surface not including the rectangular surface or the upper surface of the cube are measured, It completes by step S08. Although not shown in FIG. 6, the phase reference point antenna 11 shown in FIG. 1 is rotated by the rotator 12 from the position of θ = 0 deg to the position of θ = 90 deg in synchronization with the position of the rotary table 10. . A series of operation flows are shown in FIG. The execution of this operation flow is realized by sending a scan command from the computer 17 shown in FIG. 1 to the scan controller 15. The processing performed by the arithmetic processing unit will be described in detail later.

  In addition, even if it is a cylindrical surface formed with a radius of z and perpendicular to the ground plane 1, the stay 20 of the position control scanner 9 is rotated by using the rotation table 10 at an interval of an arbitrary angle θ. By scanning up and down at the center of the specimen 2, it is possible to measure a plurality of measurement point electric fields or a plurality of measurement point magnetic fields in a cylindrical surface not including the upper surface.

  Subsequently, an example of an electromagnetic field probe which is an example of the probe 8 will be described with reference to FIGS. 8 and 9. FIG. 8 is an exploded perspective view of the electric field detection unit. FIG. 9 is an exploded perspective view of the magnetic field detection unit.

  As shown in FIG. 8, the electric field detection unit includes a printed circuit board 22 including an electric field antenna unit 21 formed of a patterned conductor layer, a shield plate 23 formed of conductors disposed above and below the printed circuit board 22, and a shield plate. A large number of through holes 24 are provided to connect the upper and lower portions of 23. The electric field antenna unit 21 constitutes a dipole antenna. A signal corresponding to the electric field detected from the electric field antenna unit 21 is supplied to the receiver via the preamplifier by the two electric field output ports 25 and 26. The two electric field output ports 25, 26 output differential signals generated by the electric field antenna unit 21. The differential signal is composed of two signals of equal amplitude and opposite in phase.

  As shown in FIG. 9, the magnetic field detection unit includes a printed circuit board 29 including a magnetic field antenna unit 27 made of a patterned conductor layer, a shield plate 30 made of a conductor provided with a minute gap 28 at its tip, and a shield plate. A large number of through holes 31 are provided to connect the upper and lower portions of 30. The magnetic field antenna unit 27 constitutes a shielded dead loop antenna having a gap 28. A signal corresponding to the magnetic field detected from the magnetic field antenna unit 27 is supplied to the receiver via the preamplifier by the two magnetic field output ports 32 and 33. The two magnetic field output ports 32 and 33 output the differential signal generated by the magnetic field antenna unit 27.

  Next, with reference to FIGS. 10 and 11, an example of an orthogonal electromagnetic field probe which is an example of the probe 8 will be described. FIG. 10 is a front view and a side view showing a cross electric field detection unit (orthogonal electric field detection unit). FIG. 11 is a front view and a side view showing a cross magnetic field detection unit (orthogonal magnetic field detection unit).

  As shown in FIG. 10, the electric field detection unit includes a cross electric field antenna portion 34 formed of crossed conductor wires, a connector 35 connecting the cross electric field antenna portion 34, and a material 36 supporting the cross electric field antenna portion 34. It consists of The crossed electric field antenna unit 34 constitutes an orthogonal dipole antenna. A signal corresponding to the electric field detected from the cross electric field antenna unit 34 is supplied to the receiver via the preamplifier by the four electric field output ports 37, 38, 39, 40. The two electric field output ports 37 and 38 and the two orthogonal electric field output ports 39 and 40 output differential signals generated by the cross electric field antenna unit 34.

  As shown in FIG. 11, the magnetic field detection unit is a material that supports the crossed magnetic field antenna unit 41 formed of a coaxial line provided with minute gaps 42 on the side surfaces arranged to cross, the connector 43 and the crossed electric field antenna unit 41 It consists of 44. The cross magnetic field antenna unit 41 constitutes a shielded dead loop antenna having a gap 42. A signal corresponding to the magnetic field detected from the cross magnetic field antenna unit 41 is supplied to the receiver via the preamplifier by the four magnetic field output ports 45, 46, 47, 48. The two magnetic field output ports 45 and 46 and the two orthogonal magnetic field output ports 47 and 48 output differential signals generated by the cross magnetic field antenna unit 41.

  As described above, both the electric field detection unit and the magnetic field detection unit generate differential signals. Such an electric field detection unit and a magnetic field detection unit can offset stationary noise generated in the same phase in the two signals constituting the differential signal, and have a feature that the dependence on the detection direction is small.

  Next, with reference to FIGS. 12 and 13, the differential signal corresponding to the electric field and the magnetic field detected by the electric field detection unit and the magnetic field detection unit is processed at high speed and in a wide band, and the amplitude and phase of the electric field and the amplitude of the magnetic field An example of a receiver for obtaining the phase and the phase will be described. FIG. 12 is a diagram showing the relationship between an electric field detection unit or a magnetic field detection unit, a phase reference point antenna, a preamplifier, and a receiver.

  As shown in FIG. 12, the differential signals detected by the probe 8 are synthesized by the 180 ° phase synthesizer 49 and taken into the receiver 14 via the preamplifier 13. Also, the signal detected by the phase reference point antenna is taken into the receiver 14 via the preamplifier 13. Since the receiver 14 is required to sample signals in high speed and in a wide band, an oscilloscope or the like equipped with a high speed and high precision analog-to-digital converter can be applied. Also, in order to obtain the phase of the differential signal detected by the probe 8, vector signal analysis software or the like that can execute phase difference analysis on the signal of the phase reference point antenna 11 can be applied.

  FIG. 13 is a diagram showing the architecture of an oscilloscope equipped with a high-speed and high-precision analog-to-digital converter and vector signal analysis software capable of phase difference analysis. As shown in FIG. 13, the probe signal and the phase reference point antenna signal are signal conditioned and digitized by an analog to digital converter via an anti-aliasing filter. Then, each digital signal is generated as a wideband vector modulation (digital modulation) signal by an orthogonal detector, and stored as time data via a digital filter. Next, the time data of each signal sampled at high speed is resampled, and the amplitude of the probe signal is transformed into the frequency domain by displaying the window function by convolution and FFT processing, and the phase of the probe signal is , Phase reference point Display the phase difference with the antenna. Here, if the frequency band is 1 GHz, the time required for one sampling is about several hundred microseconds to several milliseconds, and high speed and wide band signal processing can be realized.

  The amplitudes and phases of the electric field and the amplitudes and phases of the magnetic field measured in the above manner correspond to the amplitudes and phases of the output signal actually received by the detection portion according to the specific reception characteristics of the electric field detection portion and the magnetic field detection portion. And needs to be corrected to the value corresponding to the phase. Here, the first correction information is referred to as an electric field probe coefficient, and the second correction information is referred to as a magnetic field probe coefficient.

  In the method of determining a probe coefficient, first, an electromagnetic wave serving as a reference is emitted from a radiation source, and the electromagnetic wave is detected by an electromagnetic field probe to collect basic data for determining an electric field probe coefficient and a magnetic field probe coefficient. Here, a biconical antenna and a log-periodic antenna were used as a reference radiation source.

  The case where a biconical antenna is used as a reference radiation source will be described with reference to FIGS. 14 (a) and 14 (b). In addition to the electromagnetic field probe 8 and the biconical antenna 52, a vector network analyzer 53 was used in the method of determining the probe coefficient.

  First, as shown in FIG. 14A, the reference radiation source transmission cable 54 was connected to port 1 and port 2 of the vector network analyzer 53 for calibration. Next, as shown in FIG. 14 (b), the biconical antenna 52 and the electromagnetic field probe 8 were disposed at a height of 1 m with reference to the ground plane 1. The distance between the biconical antenna 52 and the electromagnetic field probe 8 was changed at intervals of 10 cm in the range of 30 cm to 100 m. The biconical antenna 52 was arranged to emit horizontally polarized electromagnetic waves. In the electromagnetic field probe 8, the electric field detection unit detects the horizontal component of the electric field, and the magnetic field detection unit detects the vertical component of the magnetic field. The frequencies of the electromagnetic waves emitted by the biconical antenna 52 are 30 MHz to 300 MHz, at 1 MHz intervals. The two differential signals output from the electric field detection unit and the magnetic field detection unit of the electromagnetic field probe 8 are synthesized by the 180 degree phase synthesizer, supplied to the vector network analyzer 53 via the preamplifier, and the propagation characteristics of S21 can get. The probe receiving cables 50 and 51 used were completely identical to those used for the actual measurement.

  Next, in place of the biconical antenna 52, a log-periodic antenna was arranged at a height of 1 m with reference to the ground plane 1. The distance between the log periodic antenna and the electromagnetic field probe 8 was changed at intervals of 10 cm in the range of 30 cm to 100 m. The log periodic antenna was placed in a posture for emitting horizontally polarized electromagnetic waves. The frequency of the electromagnetic wave emitted by the log periodic antenna was 300 MHz to 1 GMHz, at 1 MHz intervals. Other conditions in the case of using the log periodic antenna are the same as in the case of using the biconical antenna 52.

On the other hand, in the method of determining the probe coefficient, the respective radiation sources based on the measurement conditions shown in FIG. 14B, here, the biconical antenna and the log periodic antenna are modeled, and the reference radiation source 52 and The reference electromagnetic field intensity E ^MOM (r) and H ^MOM (r) in the absence of the electromagnetic field probe 8 were calculated at each position of the distance r of the electromagnetic field probe 8 in the range of 30 cm to 100 m and an interval of 10 cm. . Then, the reference electromagnetic field intensity and the calculated propagation characteristics of the measured S21 (r), (13), to determine the electric field probe coefficient PF _E and the magnetic field probe factor PF _H according (14).

Field probe factor PF _E and the magnetic field probe factor PF _H are respectively have information of the amplitude and phase. Here, it referred to the amplitude information of which has an electric field probe coefficient PF _E the electric field amplitude coefficient, called the phase information included in the electric field probe coefficient PF _E the electric field phase factor, the magnetic field amplitude amplitude information included in the magnetic field probe factor PF _H referred to as a coefficient, called the phase information included in the magnetic field probe factor PF _H the magnetic field phase factor.

  The electric field amplitude coefficient and electric field phase coefficient, and the magnetic field amplitude coefficient and magnetic field phase coefficient were determined by changing the distance between the biconical antenna or the log periodic antenna and the electromagnetic field probe. It turned out that it became.

Here, an average value of each of the electric field amplitude coefficient, electric field phase coefficient, magnetic field amplitude coefficient, and magnetic field phase coefficient for each frequency is described as electric field amplitude coefficient PF _Em , electric field phase coefficient PF _Ep , magnetic field amplitude coefficient PF _Hm , magnetic field phase coefficient PF _{It is} assumed _Hp . In the method of determining the probe coefficient, the electric field amplitude coefficient PF _Em is obtained as the information of the amplitude of the electric field probe coefficient, the electric field phase coefficient PF _Ep is obtained as the information of the phase of the electric field probe coefficient, and the magnetic field amplitude coefficient is obtained as the information of the magnetic field probe coefficient. The PF _Hm was determined, and the magnetic field phase coefficient PF _Hp was determined as information of the phase of the magnetic field probe coefficient.

FIG. 15A is a characteristic diagram showing an electric field amplitude coefficient PF _Em in the electric field probe of the electric field detection unit shown in FIG. FIG. 15B is a characteristic diagram showing an electric field phase coefficient _PFEp in the electric field probe of the electric field detection unit shown in FIG. Here, an electric field probe was used in which the total length of the elements of the electric field antenna unit 21 of the electric field detection unit was 50 mm.

FIG. 16A is a characteristic diagram showing the magnetic field phase coefficient PF _Hp in the magnetic field probe of the magnetic field detection unit shown in FIG. FIG. 16B is a characteristic diagram showing a magnetic field phase coefficient PF _Hp in the magnetic field probe of the magnetic field detection unit shown in FIG. Here, a magnetic field probe having a length of 20 mm on one side of the square loop of the magnetic field antenna unit 27 of the magnetic field detection unit was used. When the receiving sensitivity is required at a frequency of 300 MHz or less, a magnetic field probe having a length of 50 mm on one side of the square loop was used.

Respect electromagnetic field probe used, using an electric field probe factor PF _E, the amplitude and phase of the output signal of the electric field detection unit, the reception characteristics of the field detector, the transmission characteristics of the receiving cable, the influence of the gain of the preamplifier is eliminated The values can be corrected to values corresponding to the amplitude and phase of the electric field actually received by the electric field detector. Similarly, using a magnetic field probe factor PF _H, the amplitude and phase of the output signal of the magnetic field detecting portion, the reception characteristics of the magnetic field detecting portion, the transmission characteristics of the receiving cable, values affect the gain of the preamplifier is eliminated, i.e. the actual To the value corresponding to the amplitude and phase of the magnetic field received by the magnetic field detection unit. Specifically, the electric field after the correction is obtained by multiplying the electric field probe factor PF _E to the output signal of the electric field detector, the magnetic field after correction multiplying the magnetic field probe factor PF _H to the output signal of the magnetic field detecting portion It is obtained by

  The far electromagnetic field estimated at the far observation point does not take into consideration the effects of the receiving antenna used in the actual measurement, the receiving cable, the preamplifier, and the like. For this reason, it is necessary to correct the reception characteristics of the reception antenna to be actually used, and the loss and gain of the reception cable and preamplifier to values according to the path characteristics. Here, the third correction information for correcting the antenna characteristics is called an antenna coefficient, and the fourth correction information for correcting the route characteristics is called a path coefficient. The antenna factor and the path factor can be converted to the voltage dBV actually measured at the receiver.

  In the case of determining the antenna coefficient of the receiving antenna, the conditions for determining the probe coefficient using the above-described reference radiation source are premised. Here, with reference to FIGS. 17 and 18, a method of determining the antenna coefficient of the receiving antenna will be described.

  As shown in FIG. 17, the electromagnetic field measured in the vicinity of the specimen 2 is corrected by the probe coefficient. This means that the vicinity of the reference radiation source 52 is represented by a relative value to the electromagnetic field calculated by the method of moments. When the far electromagnetic field of the far observation point 56 is determined using these near electromagnetic fields, the far electromagnetic field of the far observation point 56 of the sample 2 is also different from the far electromagnetic field of the far observation point 56 of the reference radiation source 52. It will be expressed as a relative value. According to this precondition, the antenna factor is determined using the reference radiation source 52. Here, a biconical antenna at 30 MHz to 300 MHz and a log periodic antenna at 300 MHz to 1 GHz were used as reference radiation sources. As the receiving antenna, as with the reference radiation source 52, a biconical antenna and a log periodic antenna were used.

As shown in FIG. 18, first, in free space, the receiving antenna 55 is disposed at a distant observation point at a distance r from the reference radiation source 52, and the transmission loss characteristic, that is, the site attenuation CSA value Smith's formula Calculated by (15). Here, the free space antenna factor AF was used for the antenna factor in Smith's formula. Next, the electric field intensity E at the distant observation point 56 of the same distant distance r as the reference radiation source 52 alone is determined by the moment method, and the aforementioned CSA value is subtracted from the electric field intensity E, ie, (16) The antenna coefficient CF _AF is determined by the equation. The method of determining the antenna coefficient CF _AF is effective when the radiation position of the electromagnetic wave in the specimen 2 is unknown and the polarization is unknown. Thus, the result of having calculated | required the antenna coefficient at the time of using a receiving antenna as a biconical antenna and a log periodic antenna is shown in FIG.

On the other hand, when the radiation position of the electromagnetic wave is known in the specimen 2 and the polarization is known, the influence of the ground plane can be considered. In this case, as shown in FIG. 20, the reference radiation source 52 is disposed at the height h _Tx of the known radiation source position from the ground plane 1, and the receiving antenna 55 is disposed at the height h _Rx at the distance r of the distant observation point 56 Then, the CSA value is determined by the moment method. Next, the electric field intensity E at the distant observation point 56 of the height h _Rx is determined by the moment method at the distance r as the reference radiation source 52 alone, and the aforementioned CSA value is subtracted from the electric field intensity E (16 The antenna coefficient CF _AF is obtained by using the CSA value of equation (1) as the CSA value of the moment method.

  Which antenna factor is to be selected can be determined based on whether the position and polarization of the electromagnetic wave emitted from the sample are known or unknown.

When the receiving antenna is a biconical antenna and a log-periodic antenna at a remote observation point, the far electric field is obtained by subtracting the antenna coefficient CF _AF with respect to the far electric field E _NFT estimated by the equation (17). By adding the path factor PF _Pass which is the loss and gain of the preamplifier, it can be converted to the voltage dBV measured by a receiver such as a spectrum analyzer or an EMI receiver, for example.

  Next, the arithmetic processing unit will be described in detail with reference to FIGS. 1 and 21. FIG. 21 is a block diagram showing a hardware configuration of the computer 17 in FIG. The computer 17 includes a main control unit 66, an input device 67, an output device 68, a storage device 69, and a bus 70 connecting them. The main control unit 66 has a CPU (central processing unit) and a RAM (random access memory). The input device 67 is used to input information necessary for the operation of the far electromagnetic field estimation apparatus and to instruct various operations. The output device 68 is used to output (including display) various information related to the operation of the far electromagnetic field estimation device.

  The storage device 69 may be of any form as long as it can store information, and is, for example, a hard disk drive or an optical disk drive. In addition, the storage device 69 records information on the computer readable recording medium 71 and reproduces the information from the recording medium 71. The recording medium 71 is, for example, a hard disk or an optical disk.

  Incidentally, by executing the program recorded in the recording medium 71 of the storage device 69, the position control mechanism (scanner 9 and rotation table 10) of the probe 8 with respect to the specimen 2 shown in FIG. The function of controlling the operation of the small antenna 11 that performs phase reference of the field by the scanning controller 15 is exhibited.

  Further, by executing the program described above, a plurality of signals received by the receiver 13 are output signals obtained by the electromagnetic field probe 8 and the preamplifier 14 and output signals obtained by the reference point antenna 11 and the preamplifier 14. The function of sending a plurality of measurement data corresponding to the above to the computer 17 is exhibited.

  Next, calculation processing will be described in detail with reference to FIGS. 1 and 22. FIG. 22 is a flowchart showing arithmetic processing. As shown in FIG. 22, in the arithmetic processing, first, in step S101, the operator selects in advance the frequency of the radiation disturbance wave received by the phase reference point antenna, and the center height of the specimen 2 and the specimen Calculation conditions such as the horizontal distance r from 2 to the distant observation point, the range and interval of the angle of the specimen 2, the range and interval of the observation point height, and the polarization to be analyzed at the observation point are input. In the EMI test, the distance r is mainly 3 m or 10 m, the range of the angle of the specimen 2 is 0 degree to 360 degrees, and the range of the observation point height is 1 m to 4 m. Also, the radiation disturbance wave is expressed as the electric field strength of horizontal polarization and vertical polarization.

  Next, in step S102, the arithmetic processing unit performs a first arithmetic process. That is, the arithmetic processing unit sets a plurality of mirror image points 7 on the mirror image measurement surface 6, and performs a plurality of measurement point electric fields and / or a plurality of measurement point magnetic fields measured by the near electromagnetic field measurement apparatus Correct with the factor and the magnetic field probe factor. Then, based on the plurality of measurement point electric fields and / or the plurality of measurement point magnetic fields corrected, the plurality of mirror point electric fields and / or the plurality of mirror point magnetic fields at the plurality of mirror image points 7 are calculated.

Next, in step S103, using the equation (11), the arithmetic processing unit uses a plurality of measurement point electric fields, a plurality of measurement point magnetic fields or either, a plurality of mirror image electric fields and a plurality of mirror image magnetic fields or either Based on one side, the distribution of equivalent electromagnetic current densities J _mn and M _mn on all surfaces is determined.

Next, in step S104, the arithmetic processing unit observes from the specimen 2 from the position coordinates of the observation point at the minimum value within the range of the angle of the specimen 2 and the minimum value within the range of the observation point height which have been input The distance to the point 3 is determined, and the far electromagnetic field at the observation point 3 is calculated using the equation (10) from the distributions of the equivalent electromagnetic current densities J _mn and M _mn on all the surfaces.

Next, in step S105, with respect to the electric field strength of the far electromagnetic field calculated in S104, the reception voltage dBV which is a measured value at the receiver in consideration of the antenna coefficient CF _AF and the path coefficient PF _Pass in equation (17). Convert to and store.

  Next, in step S106, the arithmetic processing unit increases the minimum value of the observation point heights by the height interval, and executes steps S104 to S105. Then, the height pattern of the reception voltage dBV which is a measured value at the receiver at the minimum value of the angle of the specimen 2 is obtained by repeating the process until the maximum value of the observation point height.

  Next, in step S107, the arithmetic processing unit increases the minimum value of the angle of the specimen 2 by the angle interval, and executes steps S104 to S106. And it repeats to the maximum value of the angle of the specimen 2, and in step S108, the reception voltage dBV which is the measured value at the receiver at a plurality of observation points in the range of the angle of the specimen 2 and the height of the observation point Find and store the distribution.

  By the above arithmetic processing, it is possible to obtain the angle and height of the maximum reception voltage dBV at the plurality of observation points 3 within the range of the angle of the input specimen 2 and the range of the observation point height.

  Assuming that the measurement surface is a magnetic wall, based on a plurality of measurement point magnetic fields and a plurality of mirror image point magnetic fields, using the relationship of Js = 2n × H, Ms = 0 instead of (11) The far electromagnetic field at the observation point can also be calculated only by the distribution of the surface current Js on the surface.

  Also, assuming that the measurement surface is an electric wall, instead of equation (11), using the relationship of Js = 0 and Ms = −2n × E, it is possible to use a plurality of measurement point electric fields and a plurality of mirror image electric field Based on the distribution of the surface magnetic current Ms on the surface, it is also possible to calculate the far electromagnetic field at the observation point.

[Verification experiment]
Hereinafter, with reference to FIG. 23 to FIG. 26, an experiment carried out to verify the appropriateness of the far electromagnetic field estimation device and the far electromagnetic field estimation method according to the present embodiment will be described. The experiment was conducted under the condition that the electromagnetic wave emitted by the specimen 2 was horizontally polarized.

  As the pseudo noise generator, as shown in FIG. 23, a sample 2 was used in which a small biconical antenna 57 with a total length of about 40 cm was connected to a circuit board constituted by a 10 MHz crystal oscillator 58 as shown in FIG.

  In the experiment, as shown in FIG. 24, the small biconical antenna 57 was disposed at a height of 1 m from the ground plane 1 to radiate horizontally polarized electromagnetic waves.

Here, the position of the small biconical antenna 57 is defined as an orthogonal coordinate system, that is, the x-axis in a direction orthogonal to the observation point, the y-axis in the height direction above the ground plane, and the z-axis as an observation point direction. First, it is assumed that the measurement surface 4 is composed of the flat surfaces 1a, 1b, 1c and 1d not including the upper surface of the rectangular parallelepiped. The four planes correspond to the four sides of the rectangular parallelepiped which are perpendicular to the ground plane. The planes 1a and 1b are perpendicular to the x-axis, and one side of each is in contact with the ground plane 1. The planes 1 c and 1 d are perpendicular to the z-axis, and one side of each is in contact with the ground plane 1. The dimensions of the x-axis and z-axis of the measurement surface 4 were each 60 cm. In addition, the dimensions of the y-axis of the measurement surface 4 are changed to 150 cm, 180 cm, and 200 cm in order to verify the validity of the maximum height h _meas of the present embodiment, and the z-axis direction, ie, the specimen 2 The received voltage in the height range of the distant observation point 3 with an angle of 0 degrees was obtained by a series of operation and calculation processing according to the embodiment of the present invention. In addition, the distance observation point distance r was 3 m and 10 m in the EMI test, and the height range of the distance observation point 3 was 1 m to 4 m. Further, in each direction of the x, y and z axes, the distance on the measurement surface 4 between two adjacent measurement points 5 is Δx = Δy = Δz = 10 [cm].

Next, the reason for determining the height range of the y-axis of the measurement surface 4 will be described. Under the conditions described above, the center height h _EUT from the ground plane 1 of the specimen 2 is 1 m, and the maximum height h _Rx from the ground plane 1 of the distant observation point 3 is 4 m. Further, z is ± 0.3 m, and assuming that the distance of the distant observation point 3 is 3 m, the measurement height h _meas is 180 cm or more according to the equations (1) and (2). On the other hand, when the distance of the distant observation point 3 is 10 m, h _meas is 150 cm or more. Therefore, in the verification of the appropriateness of the maximum height h _meas of the present embodiment, the height range of the y axis of the measurement surface 4 is set to 150 cm, 180 cm, and 200 cm.

On the other hand, for comparison, as shown in FIG. 25 based on Patent Document 2, four faces 1a, 1b, 1c and 1d perpendicular to the ground plane set so as to surround the specimen 2 have an upper face 1e. The added measurement surface 4 was formed, and the received voltage dBV in the height range of the distant observation point 3 was determined according to Patent Document 2. The measurement height h _meas was 130 cm.

Next, with reference to FIG. 26 to FIG. 35, frequencies will be described about the results of demonstration experiments at 50 MHz, 100 MHz, 300 MHz, 500 MHz and 800 MHz. Here, height pattern characteristics of the received voltage when the distance of the distant observation point is 3 m are shown in FIG. 26 to FIG. Further, height pattern characteristics of the received voltage when the distance of the distant observation point is 10 m are shown in FIG. 31 to FIG. The broken line of the symbol H101 in each figure shows the case where the maximum height h _{meas of the} embodiment of the present invention is 200 cm, the one-dot broken line of the symbol H102 shows the case where the maximum height h _meas is 180 cm, and the two-dot broken line of the symbol H103. Indicates a case where the maximum height h _meas is 150 cm. The solid line of the symbol H104 indicates the height pattern characteristic of the reception voltage according to Patent Document 2. The antenna coefficient in consideration of the ground plane shown in FIG. 20 is used at a frequency of 300 MHz or less, and the antenna coefficient in free space shown in FIGS. 18 and 19 is used at a frequency exceeding 300 MHz.

The height pattern characteristics H101, H102, H103 of the received voltage when the distance between the distant observation points in FIGS. 26 to 30 is 3 m show the same tendency as the height pattern characteristic H104 in Patent Document 2, and H101, H102 and H104 The deviation is as small as 1 dB, except for the null point and the reception antenna height of 3 m or more at 800 MHz. On the other hand, the deviation between H103 and H104 is as large as 2 dB at 100 MHz, and at 300 MHz or more, a slight deviation occurs in the height at which the null point occurs, indicating that the deviation is large. From the above results, it can be seen that when the distance between distant observation points is 3 m, the maximum height h _meas is preferably 180 cm or more, and preferably about 200 cm.

The height pattern characteristics H101, H102 and H103 of the received voltage when the distance between the distant observation points in FIGS. 31 to 35 is 10 m show the same tendency as the height pattern characteristic H104 in Patent Document 2, and H101, H102 and H104 The deviation is within 1 dB except for the null point, which is small. On the other hand, it can be seen that the deviation between H103 and H104 is slightly larger at 100 MHz and about 1.5 dB. From the above results, it can be seen that when the distance between distant observation points is 10 m, the maximum height h _meas is preferably 150 cm or more, and preferably about 180 cm.

Next, with reference to FIGS. 36 and 38, the result of comparison between the frequency characteristic of the maximum received voltage when the maximum height h _{meas of the} embodiment of the present invention is 200 cm and the frequency characteristic of the actually measured maximum received voltage. explain.

As shown in FIG. 36, the receiving antenna 55 (biconical antenna and log periodic antenna) is disposed at the distant observation point 3, and the receiving voltage dBV supplied to the spectrum analyzer 59 via the receiving cable 60 and the preamplifier 14 is It measured and calculated | required the frequency characteristic of the largest received voltage. The path coefficient PF _Pass which is the loss and gain of the receiving cable 60 and the preamplifier 14 is obtained by measurement, and used when the frequency characteristic of the maximum received voltage in one embodiment of the present invention is obtained.

The frequency characteristic of the maximum reception voltage when the distance between distant observation points is 3 m is shown in FIG. Also, FIG. 38 shows the frequency characteristic of the maximum reception voltage when the distance between distant observation points is 10 m. In each of the figures, the symbol x represents the frequency characteristic of the maximum received voltage with a maximum height h _meas of 200 cm, and the solid line with the symbol F 2 represents the frequency characteristic of the maximum received voltage actually measured. .

  37 and 38, the frequency characteristic of the maximum received voltage according to the embodiment of the present invention of the symbol F1 is the actually measured maximum received voltage of the symbol F2 except for the frequency at which the received voltage near 30 MHz becomes very small. It can be seen that the frequency characteristics of and the good agreement are shown.

  As shown in FIG. 26 to FIG. 35, the height pattern characteristics of the received voltage according to the present embodiment are substantially the same as the characteristics of Patent Document 2 in which the upper one surface according to the comparative example is added. Further, as shown in FIG. 37 and FIG. 38, the frequency characteristic of the maximum reception voltage according to the present embodiment substantially matches the characteristic actually measured. From these results, it was confirmed that the far electromagnetic field estimation apparatus according to the present embodiment is appropriate.

Second Embodiment
Next, a second embodiment of the present invention will be described. In the second embodiment, as shown in FIG. 39, a symbol is generated using a circuit board 63 simulating a real machine of 17.5 cm long and 5 cm wide, on which a 20 MHz quartz oscillator 61 and two ICs 62 are mounted. F, symbol B, symbol R, symbol L and L are changed as the direction of the distant observation point, that is, 0 degree of specimen angle is symbol F, 90 degree is symbol R, 180 degree is symbol B, 270 As the degree symbol L, the height pattern characteristics of the received voltage at distances of 3 m and 10 m at the distant observation point were estimated, and the frequency characteristics of the maximum received voltage were obtained. And it compared with the frequency characteristic of the maximum receiving voltage actually measured.

In the second embodiment, as shown in FIG. 40, the circuit board 63 is disposed at a height of 0.8 m from the ground plane 1. Here, the position of the circuit board 63 is defined as an orthogonal coordinate system, that is, the x-axis is a direction orthogonal to the observation point, the y-axis is a height direction above the ground plane, and the z-axis is an observation point direction. First, it is assumed that the measurement surface 4 is composed of the flat surfaces 1a, 1b, 1c and 1d not including the upper surface of the rectangular parallelepiped. The four planes correspond to the four sides of the rectangular parallelepiped which are perpendicular to the ground plane. The planes 1a and 1b are perpendicular to the x-axis, and one side of each is in contact with the ground plane 1. The planes 1 c and 1 d are perpendicular to the z-axis, and one side of each is in contact with the ground plane 1. The dimensions of the x-axis and z-axis of the measurement surface 4 were 40 cm. Further, the maximum height h _meas which is the dimension of the y-axis of the measurement surface 4 is 160 cm from the equations (1) and (2), the symbol F of the circuit board 63 is 0 degrees, the symbol R of 90 degrees, and 180 The received voltage in the height range of the distant observation point 3 with respect to the direction of the symbol of degree B and the symbol L of 270 degrees was determined by a series of operation and arithmetic processing according to the first embodiment of the present invention. In addition, the distance observation point distance r was 3 m and 10 m in the EMI test, and the height range of the distance observation point 3 was 1 m to 4 m. Further, in each direction of the x, y and z axes, the distance on the measurement surface 4 between two adjacent measurement points 5 is Δx = Δy = Δz = 10 [cm]. Also, the antenna coefficient CF _AF of free space when the receiving antenna is arranged at the distant observation point, and the path coefficient PF _Pass by measurement. Was used. On the other hand, in the actual measurement, the frequency characteristic of the maximum reception voltage was measured by the measurement system of FIG.

  41 (a) symbol F, (b) symbol R, (c) symbol B, (d) symbol L, at a distance of 3 m, the frequency of the maximum reception voltage according to the second embodiment of the present invention in horizontal polarization The characteristics, the cross of the symbol F3 and the frequency characteristics of the maximum received voltage measured in the implementation, the solid line of the symbol F4 are shown. Also, in FIG. 42 (a) symbol F, (b) symbol R, (c) symbol B, (d) symbol L, at a distance of 3 m, the maximum received voltage according to the second embodiment of the present invention in vertical polarization. Of the symbol F3 and the frequency characteristics of the maximum received voltage measured in the implementation, and the solid line of the symbol F4.

  In the distance 3 m and both horizontal and vertical polarizations shown in FIGS. 41 and 42, the frequency characteristic of the maximum received voltage according to the second embodiment of the present invention of the symbol F3 is the frequency of the actually measured maximum received voltage of the symbol F4. It can be seen that the characteristic and the good match are shown.

  Next, FIG. 43 (a) symbol F, (b) symbol R, (c) symbol B, (d) symbol L, at a distance of 10 m, maximum reception according to the second embodiment of the present invention in horizontal polarization The frequency characteristics of the voltage, the crosses of the symbol F3 and the frequency characteristics of the maximum received voltage measured in the implementation, the solid line of the symbol F4 are shown. Further, in FIG. 44 (a) symbol F, (b) symbol R, (c) symbol B, (d) symbol L, the maximum received voltage according to the second embodiment of the present invention in vertical polarization at a distance of 10 m. Of the symbol F3 and the frequency characteristics of the maximum received voltage measured in the implementation, and the solid line of the symbol F4.

  In the distance 10 m and both horizontal and vertical polarizations of FIGS. 43 and 44, the frequency characteristic of the maximum received voltage according to the second embodiment of the present invention of the symbol F3 is the frequency of the actually measured maximum received voltage of the symbol F4. It can be seen that the characteristic and the good match are shown.

  As shown in FIGS. 41 to 44, the frequency characteristics of the maximum reception voltage according to the second embodiment of the present invention substantially match the characteristics actually measured. From these results, it is confirmed that the far electromagnetic field estimation device is appropriate even when the specimen angle is changed every 90 degrees using the circuit board simulating the actual machine according to the embodiment of the present invention. The

Third Embodiment
Next, a third embodiment of the present invention will be described. In the third embodiment, one emotion engine operating at a clock frequency of 295 MHz, one graphic synthesizer operating at a clock frequency of 147.5 MHz, and a large number of I / O processors operating at a clock frequency of 34 MHz to 38 MHz. Using the game machine with a length of 30 cm, a width of 20 cm, and a height of 10 cm, the angle of the game machine is changed in the range of 0 degree to 360 degrees to estimate the height pattern characteristics of the received voltage at a distance of 3 m The frequency characteristics of the maximum received voltage were determined. Then, the angle of the game machine was actually changed by the turntable within the range of 0 degree to 360 degrees, and the frequency characteristic of the maximum received voltage at a distance of 3 m from the distant observation point was measured.

In the third embodiment, as shown in FIG. 45, the game machine 64 is disposed at a height of 0.8 m from the ground plane 1. Here, the position of the game machine 64 is defined as an orthogonal coordinate system, that is, the x-axis is a direction orthogonal to the observation point, the y-axis is a height direction above the ground plane, and the z-axis is an observation point direction. First, it is assumed that the measurement surface 4 is composed of the flat surfaces 1a, 1b, 1c and 1d not including the upper surface of the rectangular parallelepiped. The four planes correspond to the four sides of the rectangular parallelepiped which are perpendicular to the ground plane. The planes 1a and 1b are perpendicular to the x-axis, and one side of each is in contact with the ground plane 1. The planes 1 c and 1 d are perpendicular to the z-axis, and one side of each is in contact with the ground plane 1. The dimensions of the x-axis and z-axis of the measurement surface 4 were each 60 cm. Also, assuming the maximum height h _meas which is the dimension of the y axis of the measurement surface 4 to be 160 cm from the equations (1) and (2), the angle of the game machine is in the range of 0 degree to 360 degrees for every 5 degrees interval The received voltage in the height range of the distant observation point 3 was determined by a series of operation and calculation processing according to the first embodiment of the present invention. In addition, the distance station distance r was 3 m in the EMI test, and the height range of the distance station 3 was 1 m to 4 m. Further, in each direction of the x, y and z axes, the distance on the measurement surface 4 between two adjacent measurement points 5 is Δx = Δy = Δz = 10 [cm]. Also, the antenna coefficient CF _AF of free space when the receiving antenna is arranged at the distant observation point, and the path coefficient PF _Pass by measurement. Was used. On the other hand, in the actual measurement, with the measurement system shown in FIG. 46, the game machine 64 is disposed on the turn table 65, and the frequency characteristic of the maximum reception voltage for every 5 degrees interval is measured in the range of 0 degrees to 360 degrees. did.

  As shown in the example of FIG. 47, among the radiated disturbance waves radiated from the game machine, three frequencies of 373 MHz of symbol F101, 590 MHz of symbol F102, and 786 MHz of symbol F103 are selected, and the third of the present invention is applied. The estimation results of the embodiment and the actually measured results were compared.

  Here, at 373 MHz of the symbol F101, the horizontal axis represents the angle of the game machine, and the vertical axis represents the height of the receiving antenna. The results of determining the distribution of the maximum received voltage are shown in FIGS. 48 (a), (b) and 49. It shows in (a) and (b). Further, the results of obtaining the distribution of the maximum reception voltage at 590 MHz of symbol F102 are shown in FIGS. 50 (a), (b) and FIGS. 51 (a), (b). Furthermore, the results of obtaining the distribution of the maximum reception voltage at 786 MHz of symbol F102 are shown in FIGS. 52 (a) and (b) and FIGS. 53 (a) and (b). Note that (a) shows the estimation result of the third embodiment of the present invention, and (b) shows the result of actual measurement.

  In the distance 3 m and both horizontal and vertical polarizations of FIGS. 48 to 53, it can be seen that the estimation result of the reception voltage distribution according to the third embodiment of the present invention is in good agreement with the actual measurement result.

  From these results, the far electromagnetic field estimation apparatus is appropriate even when the angle of the game machine and the height of the receiving antenna are finely changed using the game machine according to the third embodiment of the present invention. That was confirmed.

Reference Signs List 1 ground plane 2 sample 3 observation point 4 measurement surface 5 measurement point 6 mirror image measurement surface 7 mirror image point 8 probe 9 scanner 10 rotation base 11 phase reference point antenna 12 rotator 13 Receiver 14 ... Preamplifier 15 ... Controller for scanning 16 ... Cable for control 17 ... Computer for measurement control and calculation 18 ... Communication cable 19 ... Carriage 20 ... Styling 21 ... Electric field antenna 22 25 ... Port 1
26 ... Port 2 27 ... Magnetic field antenna part 28 ... Gap 29 ... Printed circuit board
30 ... shield plate 31 ... through hole 32 ... port 1 33 ... port 2
34 ... electric field antenna unit 35 ... connector 36 ... support material 37 ... Port 1
38 ... Port 2 39 ... Port 3 40 ... Port 4
DESCRIPTION OF SYMBOLS 41 ... Magnetic field antenna part 42 ... Gap 43 ... Insulator 44 ... Support material 45 ... Port1 46 ... Port2 47 ... Port 3 48 ... Port 4
49 ... 180 degree phase synthesizer 50, 51 ... Reception cable for probe 52 ... Reference radiation source 53 ... Vector network analyzer 54 ... Transmission cable for reference radiation source 55 ... Reception antenna 56 ... Far observation point 57 ... Small biconical antenna 58 ... 10 MHz crystal oscillator 59 ... spectrum analyzer 60 ... reception cable 61 ... 20 MHz crystal oscillator 62 ... IC 63 ... circuit board 64 ... game machine 65 ... turntable 66 ... main control unit 67 ... input device 68 ... output device 69 ... storage device 70: bus 71: storage medium E1: parallel component of electric field E2: vertical component of electric field E3: parallel component of mirror electric field E4: vertical component of mirror electric field H1: parallel component of magnetic field H2: vertical component of magnetic field H3: of mirror magnetic field Parallel component H4: Vertical component of mirror image magnetic field H101: Invention 200 cm H1 2 ... the present invention 180cm
H103: present invention 150 cm H104: in the case of Patent Document 2 F1: estimated result of the present invention F2: measurement result F101, F102, F103: comparative examination frequency

Claims (12)

A far electromagnetic field estimation apparatus for obtaining at least one of an electric field and a magnetic field formed at a distant observation point at a distance r from a test object by a test object which is a radiation source of an electromagnetic wave disposed above a ground plane,
A near electromagnetic field measurement device and an arithmetic processing unit;
The near electromagnetic field measurement device is
A probe for detecting at least one of an electric field and a magnetic field;
An antenna that references the phase of the electric and magnetic fields,
A position control mechanism capable of changing the relative position of the probe with respect to the specimen;
A control unit configured to control measurement of at least one of an electric field and a magnetic field using the probe, the antenna, and the position control mechanism;
The control unit
Assuming that the y-axis is in the height direction above the ground plane, the z-axis is in the direction of the observation point, and the x-axis is in the direction orthogonal to the y-axis and the z-axis based on the position of the specimen. Assuming a forward measurement plane at a position separated by a distance + z (a distance z is sufficiently smaller than the distance r) forward from the sample, the center height h _EUT from the ground plane of the sample and the ground plane of the distant observation point The straight line connecting the maximum height h _Rx is determined by the following equation (1) with the height from the ground plane intersecting the front measurement surface as the reference height href

Assuming a rear measurement plane at a position separated by an equal distance -z backward from the sample in the same way as the front, a straight line connecting the reference height href in the rear measurement plane and the maximum height h _Rx of the distant observation point The measurement height h meas is determined by the following equation (2) on the basis of the height intersecting the front measurement surface,

The specimen is formed with a distance of + z forward, -z backward, + x leftward -x rightward (x is smaller than distance r), vertical to the ground plane, and height On each measurement plane (including the front measurement plane and the rear measurement plane) not more than the measurement height h meas, or + z = + x on the front, -z = -x on the rear, + z on the left Each measuring plane formed at a distance of -z = -x to the right and perpendicular to the ground plane and having a height equal to or less than the measurement height h meas (the front measuring plane and the rear measuring plane Or the first operation of forming a plurality of measurement points on a measurement surface whose radius is formed at a distance of z apart and perpendicular to the ground plane and whose height is equal to or less than the measurement height h meas ;
A plurality of measurement point electric fields which are tangential components of the measurement surface of the electric field at the plurality of measurement points using the probe, the antenna, and the position control mechanism, and the measurement surfaces of the magnetic field at the plurality of measurement points Performing a second operation of measuring at least one of the plurality of measurement point magnetic fields that are components of the tangential direction of
The arithmetic processing unit
A plurality of mirror image points having a positional relationship of plane symmetry with the plurality of measurement points with respect to the ground plane are set on a mirror image measurement plane having a positional relationship of plane symmetry with the measurement plane with the ground plane as a center. A plurality of tangential direction components of the mirror image measurement surface of the electric field at the plurality of mirror image points based on at least one of the plurality of measurement point electric fields and the plurality of measurement point magnetic fields measured in the second operation. A first calculation process for calculating at least one of a mirror image point electric field and a plurality of mirror image point magnetic fields that are components of the mirror image measurement surface tangential direction of the magnetic field at the plurality of mirror image points;
At least one of the plurality of measurement point electric fields measured in the second operation and the plurality of measurement point magnetic fields, the plurality of mirror image electric fields calculated in the first arithmetic processing, and the plurality of mirror image magnetic fields A far electromagnetic field estimation apparatus, which executes second arithmetic processing for calculating at least one of an electric field and a magnetic field at the distant observation point based on at least one of the two. The plurality of measurement points are arranged in two intersecting directions, and in each of the two directions, the distance on the measurement plane between two adjacent measurement points is less than or equal to half the wavelength of the electromagnetic wave. The far electromagnetic field estimation apparatus according to claim 1, wherein the apparatus comprises: An antenna which refers to the phase is provided outside the measurement surface, and it is characterized in that the distance and the positional relationship with the sample are always constant in synchronization with the position of the sample. The far electromagnetic field estimation apparatus according to 1 or 2. The plurality of measuring point electric fields, the plurality of measuring point magnetic fields, the plurality of mirror point electric fields, and the plurality of mirror point magnetic fields respectively have a horizontal component parallel to the ground plane and a vertical component perpendicular to the ground plane. Including
The horizontal components of the plurality of mirror point electric fields are equal in amplitude but opposite in phase to the horizontal components of the corresponding measurement point electric fields, respectively.
The vertical components of the plurality of mirror point electric fields are equal in amplitude and phase to the vertical components of the corresponding measurement point electric fields, respectively.
The horizontal components of the plurality of mirror point magnetic fields are equal in amplitude and phase to the horizontal components of the corresponding measurement point magnetic fields, respectively.
The far electromagnetic field estimation apparatus according to any one of claims 1 to 3, wherein the vertical components of the plurality of mirror image magnetic fields are equal in phase but opposite in phase to the vertical components of the corresponding measurement point magnetic fields, respectively. . The said test object, the said probe, the said position control mechanism, and the said antenna are arrange | positioned in the electromagnetic wave anechoic chamber which has a metal floor surface which comprises the said ground plane, Far electromagnetic field estimation device. The far electromagnetic field according to any one of claims 1 to 5, wherein the probe includes an electric field detection unit that outputs a signal according to an electric field, and a magnetic field detection unit that outputs a signal according to a magnetic field. Estimator. In order to detect a horizontal component parallel to the ground plane and a vertical component perpendicular to the ground plane in the measurement of the plurality of measurement point electric fields or the plurality of measurement point magnetic fields, the probe detects a quadrature electric field, or The far electromagnetic field estimation apparatus according to any one of claims 1 to 5, further comprising an orthogonal magnetic field detection unit. The electric field detection unit includes an electric field antenna unit that generates a differential signal according to the electric field, two electric field output ports that output a differential signal generated by the electric field antenna unit, and a part of the electric field antenna unit. Including an electric field shield part to shield,
The magnetic field detection unit includes a magnetic field antenna unit that generates a differential signal according to a magnetic field, two magnetic field output ports that output a differential signal generated by the magnetic field antenna unit, and a part of the magnetic field antenna unit. The far electromagnetic field estimation apparatus according to claim 6, further comprising: a magnetic field shield part to be shielded. First correction information for correcting the amplitude and phase of the output signal of the electric field detector to values corresponding to the amplitude and phase of the electric field actually received by the electric field detector, and the output signal of the magnetic field detector Second correction information for correcting the amplitude and phase of the magnetic field to values corresponding to the amplitude and phase of the magnetic field actually received by the magnetic field detection unit,
The far electromagnetic field estimation according to claim 6, wherein the arithmetic processing unit calculates the plurality of measurement point electric fields and the plurality of measurement point magnetic fields based on the first and second correction information. apparatus. The arithmetic processing unit
In order to correct the electric field of the distant observation point to a value measured by an actual receiver, third correction information for correcting the receiving antenna characteristic and fourth correction information for correcting the path characteristic are previously obtained. The far electromagnetic field estimation apparatus according to any one of claims 1 to 5, wherein the voltage is converted into a voltage measured by a receiver based on the third and fourth correction information. For the third correction information, in free space, from the radiation source serving as a reference, a receiving antenna is disposed at the distant observation point and a transmission loss is determined using a free space antenna factor, and then the radiation serving as the reference The far electromagnetic field estimation apparatus according to claim 10, wherein electric field strength at the far observation point is determined as the source only, and the transmission loss is subtracted from the electric field strength. In the third correction information, a reference radiation source is disposed at an arbitrary height from a ground plane, a receiving antenna is disposed at the far observation point, and a transmission loss is determined, and then the reference radiation source 11. The far electromagnetic field estimation apparatus according to claim 10, wherein electric field strength at the far observation point is determined as the distance field only, and the transmission loss is subtracted from the electric field strength.

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