JP7172084B2 - Electric field probe and electric field measurement system - Google Patents

Description

The present invention relates to electric field probes and electric field measurement systems that can be used, for example, to identify noise sources.

2. Description of the Related Art In recent years, as home appliances, industrial equipment, automobiles, and the like have become electronic and electrified, EMC (Electro-magnetic Compatibility) countermeasures due to the effects on the human body and equipment are becoming more important. Therefore, it is essential to deal with noise in product development. In product development, it is very difficult to keep the interference wave below the allowable value, and the main reason for this is that the source of the interference wave cannot be identified.

In general, as a countermeasure against a product with noise exceeding the standard value, take out the internal module that is considered to be the cause of the noise from the case of the product, and measure the electromagnetic field intensity distribution of the parts in the close vicinity of the internal module. Measure, identify the source of noise, and take countermeasures. Current near-field electromagnetic field evaluations are predominantly based on magnetic field distributions measured by electric field probes with a simple structure. However, accurate acquisition of high-resolution electric field distribution is also an important key to identifying noise sources.

To obtain a high-resolution electric field distribution, it is necessary to bring the electric field probe close to the radiation source. This will be explained with reference to FIG. FIG. 17 shows lines of electric force when one of two adjacent charges has a positive charge and the other has a negative charge. From FIG. 17, the density of the lines of electric force is higher near the charge. Therefore, the closer the electric field probe is to the charge, the more detailed the shading of the lines of electric force can be captured, that is, the higher the resolution of the electric field distribution can be obtained.

For electric field measurements, electric field probes (FIG. 18) that acquire components perpendicular to the module substrate of interest are widely available commercially. This electric field probe has a structure in which the tip of an inner conductor 81 of a coaxial cable protrudes from an outer conductor 82 . However, the electric lines of force of the electric field generated on the substrate to be measured are generated not only in the direction perpendicular to the substrate but also in the direction parallel to the substrate. For this reason, noise source identification requires not only acquisition of the component of the electric field emitted from the noise source perpendicular to the substrate (hereafter referred to as “substrate-perpendicular component”) but also the Notation) is also an important factor.

Patent No. 5772392 Patent No. 6063823

Patent document 1 discloses an electric field probe with a simple structure in which a coaxial cable is separated, as shown in FIG. In this construction, inner conductor 81 does not protrude from outer conductor 82 . FIG. 20 is a cross-sectional view when trying to acquire the electric field distribution from the microstrip line 50 with the electric field probe shown in FIG. The receiving structure of FIG. 20 is a structure for receiving only the component perpendicular to the substrate, and it is impossible to receive the component parallel to the substrate. In order to solve this problem, it is possible to obtain a substrate parallel component by placing an electric field probe parallel to the substrate in FIG. However, with an electric field probe with this structure, if you try to measure at a short distance to obtain a high-resolution electric field distribution, the electric field probe and the measurement target will come into contact with each other, making the measurement itself impossible and making it impossible to obtain a high-resolution electric field distribution. There is a problem that there is no

Patent Document 2 discloses an electric field probe characterized by a differential structure in which two coaxial cables 85 and 86 are arranged side by side, as shown in FIG. This electric field probe has a structure in which the tip portions are bent 90 degrees in opposite directions, and a substrate parallel component can be obtained by setting the tip portions so as to be parallel to the substrate. However, as with the electric field probe of Patent Document 1, when trying to measure at a short distance to obtain a high-resolution electric field distribution, the electric field probe and the measurement target come into contact, resulting in a problem that a high-resolution electric field distribution cannot be obtained. There is

The present invention has been made in recognition of such circumstances, and an object thereof is to provide an electric field probe and an electric field measurement system capable of obtaining a high-resolution electric field distribution.

One aspect of the invention is an electric field probe. This electric field probe
first and second conductors parallel to each other;
first and second conductors parallel to the first and second conductors provided on a plane containing the first and second conductors ;
there is no conductor connecting the ends of the first and second conductors on the plane parallel to the plane;
a line segment of length w connecting the tips of the first and second conductors on the plane is perpendicular to the first and second conductors;
distances d between two intersections of the line segment and two perpendicular lines drawn from the ends of the first and second conductors to the line segment and the center of the line segment are equal to each other, and 0<d <w/2,
each of the first and second conductors has a distance h from its tip to the line segment of 0≦h≦w/2−d, or does not intersect the line segment;
Structures other than on said plane are symmetrical about said plane.

The first and second conductors may be part of a common conductor covering the first and second conductors without contacting the first and second conductors.

Another aspect of the invention is an electric field probe. This electric field probe
first and second conductors parallel to each other;
First to third conductors parallel to the first and second conductors provided on a plane containing the first and second conductors,
the third conductor is centrally located between the first and second conductors;
a line segment of length w connecting the tips of the first and second conductors on the plane is perpendicular to the first and second conductors;
distances d between two intersections of the line segment and two perpendicular lines drawn from the ends of the first and second conductors to the line segment and the center of the line segment are equal to each other, and 0<d <w/2,
each of the first and second conductors has a distance h from its tip to the line segment of 0≦h≦w/2−d, or does not intersect the line segment;
Structures other than on said plane are symmetrical about said plane.

The first conductor is a part of a conductor that covers the first conductor without contacting the conductor,
The second conductor is a part of the conductor that covers the second conductor without contacting the conductor ,
The third conductor may be a mutual contact between the conductor covering the first conductor and the conductor covering the second conductor .
The line segment may be parallel to a straight line connecting the ends of the first and second conductors.

Another aspect of the invention is an electric field probe. This electric field probe
first and second conductors parallel to each other;
a first conductor that covers the first conductor without contacting the conductor;
a second conductor that covers the second conductor without contacting the conductor,
outer peripheral surfaces of the first and second conductors are in contact with each other;
When the existence plane of the tips of the first and second conductors is the first plane,
whether the projection length of the tips of the first and second conductors from the first plane is within half the diameter of the first and second conductors;
whether the tips of the first and second conductors lie in the first plane;
whether the tips of the first and second conductors are recessed with respect to the first plane;
is either
A differential signal of the signals received on the first and second conductors is output .
The first conductor and the first conductor constitute a first coaxial line,
The second conducting wire and the second conductor may form a second coaxial line.
Another aspect of the invention is an electric field probe. This electric field probe
first and second conductors parallel to each other;
a common conductor covering the first and second conductors without contacting the first and second conductors;
a line segment of length w connecting the tips of the common conductors on a plane containing the first and second conductors is perpendicular to the first and second conductors;
distances d between two intersections of the line segment and two perpendicular lines respectively drawn from the ends of the first and second conductors to the line segment and the center of the line segment are equal to each other and 0<d <w/2,
Each of the first and second conductors has a distance h from its tip to the line segment that is 0≦h≦w/2−d, or does not intersect the line segment.

Another aspect of the invention is an electric field measurement system. This electric field measurement system
the electric field probe;
a probe scanning mechanism capable of moving the electric field probe in at least two of the three axial directions in space;
a controller that controls the probe scanning mechanism;
a measuring instrument capable of measuring an electric field value at a predetermined position through the electric field probe;
and an arithmetic device that outputs the electric field value measured by the measuring device in correspondence with the measurement position.

Any combination of the above constituent elements, and conversion of expressions of the present invention between methods and systems are also effective as embodiments of the present invention.

According to the present invention, it is possible to provide an electric field probe and an electric field measurement system capable of obtaining a high-resolution electric field distribution.

1 is a schematic perspective view of the electric field probe 1 according to Embodiment 1 of the present invention, in which the first conductor 11 of the first coaxial line 10 is at a high potential and the second conductor 21 of the second coaxial line 20 is at a low potential. The schematic perspective view which also showed the electric line of force in the case where FIG. 2 is a cross-sectional view taken along the line bb′ of FIG. 1 showing lines of electric force in the same case. FIG. 2 is a cross-sectional view taken along the line bb′ of FIG. 1 showing electric lines of force left after the opposing electric fields cancel each other in the same case. 4 is a schematic perspective view of the tip of an electric field probe according to Comparative Example 1. FIG. FIG. 5A is an electric field intensity distribution diagram obtained by numerical analysis of the intensity distribution of the component in the direction perpendicular to the Y direction of the electric field generated by the electric field probe 1 when the electric field probe 1 is used as a transmitting antenna. FIG. 5B shows an electric field intensity distribution calculated by numerical analysis of the intensity distribution of the component in the direction perpendicular to the Y direction of the electric field generated by the electric field probe according to Comparative Example 1 when it is used as a transmitting antenna. figure. The electric field strength distribution (solid line a) at a position (Y = 2 mm) shifted by 2 mm in the +Y direction from the tips of the first conductor 12 and the second conductor 22 of the electric field probe according to Comparative Example 1, and the first The electric field strength distribution at a position shifted by 2 mm in the +Y direction (Y = 2 mm) from the tip of the conductor 12 and the second conductor 22 (dashed line s), the electric field strength distribution at a position shifted by 3.8 mm (Y = 3.8 mm) (dashed line t), a graph showing the electric field intensity distribution (broken line u) at a position shifted by 5.6 mm (Y=5.6 mm). Y = 2.0 + x mm to 7.0 + x of the electric field probe 1 in which the diameter of the first conductor 12 and the second conductor 22 is 3.6 mm and the electric field probe 1 in which the diameter of the first conductor 12 and the second conductor 22 is 1.2 mm mm and the electric field strength distribution in the range of Y = 2.0 mm to 7.0 mm of the electric field probe according to Comparative Example 1 in which the diameter of the first conductor 12 and the second conductor 22 is 1.2 mm. The graph which calculated|required the relational coefficient by numerical analysis, and showed it with the relationship with respect to the offset amount x. 4 is a schematic diagram showing how the electric field probe 1 measures the electric field distribution on the microstrip line 50. FIG. 1 is a schematic block diagram of an electric field measurement system using an electric field probe 1; FIG. FIG. 2 is a schematic external view of the electric field measurement system; A sine wave of 100 MHz was input from the signal generator to the microstrip line 50 shown in FIG. A graph showing the analytical value (solid line) and . FIG. 12(A) is a schematic perspective view of the distal end portion of the electric field probe 2 according to Embodiment 2 of the present invention. FIG. 12B is a schematic perspective view of the distal end portion of the electric field probe 3 according to Embodiment 3 of the present invention. FIG. 13A is an electric field intensity distribution diagram obtained by numerical analysis of the intensity distribution of the component in the direction perpendicular to the Y direction of the electric field generated by the electric field probe 2 when the electric field probe 2 is used as a transmitting antenna. FIG. 4 is an electric field intensity distribution diagram obtained by numerical analysis of the intensity distribution of the component in the direction perpendicular to the Y direction of the electric field generated by the electric field probe 3 when the electric field probe 3 is used as a transmitting antenna. FIG. 4 is a schematic configuration diagram of an electric field probe 4 according to Embodiment 4 of the present invention; 15A is a schematic configuration diagram of an electric field probe according to Comparative Example 2. FIG. FIG. 15B is a schematic configuration diagram of an electric field probe 5 according to Embodiment 5 of the present invention. FIG. 15C is a schematic configuration diagram of an electric field probe 6 according to Embodiment 6 of the present invention. FIG. 15D is a schematic configuration diagram of an electric field probe 7 according to Embodiment 7 of the present invention. FIGS. 16(A) to 16(D) show the distribution of the component of the electric field generated by the electric field probe in each configuration of FIGS. The electric field distribution diagram which shows the result calculated by. FIG. 4 is a diagram showing lines of electric force when one of two adjacent charges has a positive charge and the other has a negative charge. FIG. 2 is a schematic perspective view of an electric field probe according to Conventional Example 1; FIG. 19A is a schematic perspective view of an electric field probe according to Conventional Example 2; FIG. 19(B) is an external view of the electric field probe viewed from the tip side. FIG. 11 is a cross-sectional view when trying to obtain an electric field distribution from a microstrip line 50 by using an electric field probe according to Conventional Example 2; FIG. 11 is a schematic perspective view of an electric field probe according to Conventional Example 3;

Preferred embodiments of the present invention will be described in detail below with reference to the drawings. The same or equivalent constituent elements, members, etc. shown in each drawing are denoted by the same reference numerals, and duplication of description will be omitted as appropriate. Moreover, the embodiments are illustrative rather than limiting the invention, and not all features and combinations thereof described in the embodiments are necessarily essential to the invention.

(Embodiment 1)
Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 11. FIG. As shown in FIGS. 1 to 3, the electric field probe 1 of this embodiment includes a first coaxial line (first coaxial cable) 10 and a second coaxial line (second coaxial cable) 20. As shown in FIGS. The first coaxial line 10 has a first conductor (first inner conductor) 11 , a first conductor (first outer conductor) 12 and a first dielectric 13 . The second coaxial line 20 has a second conductor (second inner conductor) 21 , a second conductor (second outer conductor) 22 and a second dielectric 23 . The first conducting wire 11 and the second conducting wire 21 are parallel to each other and constitute two parallel lines for differential transmission. The first conductor 12 and the second conductor 22 have the same diameter, are grounded together, and are in contact with each other at their outer peripheral surfaces. A first dielectric 13 fills between the first conductor 11 and the first conductor 12 . A second dielectric 23 fills between the second conductor 21 and the second conductor 22 . The first dielectric 13 and the second dielectric 23 may be air. The electric field probe 1 is obtained by separating two coaxial lines and arranging them in parallel and in contact with each other.

In this embodiment, as shown in FIGS. 1 to 3, XYZ axes, which are orthogonal three axes, are defined. The extending direction of the first conducting wire 11 and the second conducting wire 21 is the Y direction, the direction perpendicular to the Y direction and parallel to the plane on which the first conducting wire 11 and the second conducting wire 21 exist is the Z direction, and the direction perpendicular to the plane is It is the X direction. As shown in FIG. 1, the Y-direction positions of the tips of the first conductor 12 and the second conductor 22 are equal to each other. Hereinafter, the plane on which the tips of the first conductor 12 and the second conductor 22 exist is also referred to as a "probe plane". The Y coordinate of the tip positions of the first conductor 12 and the second conductor 22 (the Y coordinate of the probe plane) is set to Y=0. The Y-direction positions of the tips of the first conductor 11 and the second conductor 21 are equal to each other and the Y-direction positions of the tips of the first conductor 12 and the second conductor 22 . As shown in FIG. 2, the Z coordinate of the mutual contact position between the first conductor 12 and the second conductor 22 is assumed to be Z=0.

1 and 2 also show lines of electric force when the first conducting wire 11 is at a high potential and the second conducting wire 21 is at a low potential. FIG. 3 also shows lines of electric force remaining after the opposing electric fields cancel each other out in the same case. From the electric lines of force shown in FIG. 3, it can be seen that an electric field strength parallel to the Z direction can be obtained. Further, if the structure is symmetrical about the plane including the first conductor 11 and the second conductor 21, the components in the directions other than the Z direction are cancelled, and an electric field intensity parallel to the Z direction can be obtained. 1 to 3 show electric field lines when transmitted from the electric field probe 1, but due to reciprocity, the electric field probe 1 can receive an electric field parallel to the Z direction. The electric field probe 1 outputs a differential signal of the signals received by the first conductor 11 and the second conductor 21 .

Compared with the electric field probe 1 of the present embodiment, the electric field probe of Comparative Example 1 shown in FIG. also project in the +Y direction, the tip of the first conductor 11 is bent in the -Z direction, and the tip of the second conductor 21 is bent in the +Z direction. The electric field probe of Comparative Example 1 is a dipole element formed by bending the ends of the first conducting wire 11 and the second conducting wire 21 (hereinafter also referred to as "dipole probe").

FIG. 5A is an electric field intensity distribution diagram obtained by numerical analysis of the intensity distribution of the component in the direction perpendicular to the Y direction of the electric field generated by the electric field probe 1 when the electric field probe 1 is used as a transmitting antenna. FIG. 5B shows an electric field intensity distribution calculated by numerical analysis of the intensity distribution of the component in the direction perpendicular to the Y direction of the electric field generated by the electric field probe according to Comparative Example 1 when it is used as a transmitting antenna. It is a diagram. The electric field strength distribution of FIG. 5A is obtained when the diameter of the first conductor 12 and the second conductor 22 is 3.6 mm. The electric field strength distribution in FIG. 5B is such that the diameter of the first conductor 12 and the second conductor 22 is 1.2 mm, and the first conductor 11 and the second conductor 21 are the tips (probes) of the first conductor 12 and the second conductor 22. 0.6 mm in the +Y direction (Y=0.6 mm) and bent 90 degrees to form a dipole element with an element diameter of 1.2 mm. 5(A) and 5(B), the electric field probe 1 of the present embodiment is compared with the electric field probe of Comparative Example 1, and the tips of the first conductor 12 and the second conductor 22 (probe ) are the same in the Y direction, but it can be confirmed that the electric field intensity distribution is shifted in the +Y direction. Details of this deviation will be described with reference to FIG.

FIG. 6 shows the electric field intensity distribution (solid line a) at a position (Y = 2 mm) shifted by 2 mm in the +Y direction from the tips of the first conductor 12 and the second conductor 22 of the electric field probe according to Comparative Example 1, and the electric field probe Electric field intensity distribution (dashed line s) at a position shifted by 2 mm in the +Y direction (Y = 2 mm) from the tip of the first conductor 12 and the second conductor 22 of 1, electric field at a position shifted by 3.8 mm (Y = 3.8 mm) It is a graph showing the intensity distribution (broken line t) and the electric field intensity distribution (broken line u) at a position shifted by 5.6 mm (Y=5.6 mm). It can be seen from FIG. 6 that the trends of the solid line a and the dashed line t are similar.

FIG. 7 shows Y=2.0+x of the electric field probe 1 in which the diameter of the first conductor 12 and the second conductor 22 is 3.6 mm and the electric field probe 1 in which the diameter of the first conductor 12 and the second conductor 22 is 1.2 mm. The electric field strength distribution in the range of mm to 7.0 + x mm and the electric field strength distribution in the range of Y = 2.0 mm to 7.0 mm of the electric field probe according to Comparative Example 1 in which the diameter of the first conductor 12 and the second conductor 22 is 1.2 mm , and is a graph showing the correlation coefficient with respect to the offset amount x obtained by numerical analysis. In FIG. 7, the solid line shows the results of the electric field probe 1 with the first conductor 12 and the second conductor 22 having a diameter of 3.6 mm, and the dashed line shows the electric field probe with the first conductor 12 and the second conductor 22 having a diameter of 1.2 mm. 1 results are shown. From FIG. 7, in the electric field probe 1 in which the diameter of the first conductor 12 and the second conductor 22 is 3.6 mm, the correlation coefficient becomes maximum when the offset amount x is around 1.2 mm. In the electric field probe 1 in which the diameter of the first conductor 12 and the second conductor 22 is 1.2 mm, the correlation coefficient becomes maximum when the offset amount x is 0.0 mm. In the electric field probe according to Comparative Example 1, the electric field at the position of the dipole element can be measured, and reciprocity is established. The electric field at the position (Y = 1.8 mm if the diameter is 3.6 mm, Y = 0.6 mm if the diameter is 1.2 mm) shifted from (Y = 0) by half the distance of those diameters can be measured in the same way as In addition to this, since the electric field probe 1 does not have a structure on the +Y direction side of the first conductor 12 and the second conductor 22, the electric field probe 1 can be brought close to the object to be measured within a range that does not contact the object to be measured. , the electric field in the immediate vicinity of the object to be measured can be measured without touching the object to be measured, and the electric field can be measured with higher resolution. That is, the electric field probe 1 of the present embodiment can suitably measure an electric field at a position close to the object to be measured, which cannot be measured by the electric field probe (dipole probe) according to Comparative Example 1, and can achieve high resolution. Electric field distribution can be obtained.

FIG. 8 is a schematic diagram showing how the electric field probe 1 measures the electric field distribution on the microstrip line 50. As shown in FIG. The microstrip line 50 has one signal line 52 on the front surface of a dielectric substrate 51 and a ground pattern 53 on the back surface. The microstripline 50 is designed for 50Ω and terminated with 50Ω (termination resistor 55 is 50Ω).

FIG. 9 is a schematic block diagram of an electric field measurement system using the electric field probe 1. As shown in FIG. FIG. 10 is a schematic external view of the electric field measurement system. This electric field measurement system includes a probe scanning device (probe scanning mechanism) 62 capable of scanning the electric field probe 1 in the XYZ directions, and a differential signal output circuit 64 that receives measurement signals from the electric field probe 1 and outputs differential signals. , a measuring instrument 63 for measuring an electric field at a predetermined position based on a signal from a differential signal output circuit 64 , and a control device 61 for controlling the probe scanning device 62 and the measuring instrument 63 . The differential signal output circuit 64 may be a circuit that outputs a differential signal, such as a hybrid junction, or may be software arithmetic processing of the measuring instrument 63 or the like. The control device 61 also functions as an arithmetic device that outputs the electric field value measured by the measuring device 63 in correspondence with the measurement position. The test piece 70 is, for example, an internal module substrate that may cause noise.

In FIG. 11, a sine wave of 100 MHz is input from a signal generator to the microstrip line 50 shown in FIG. 10 is a graph showing measurement results (broken line) when the measurement was performed using the same, and analytical values (solid line) obtained by calculation. Measurement and analysis of the electric field distribution The height is 1 mm above the signal line 52 of the microstrip line 50, and the measurement is performed by moving the probe surface of the electric field probe 1 from the measurement height to the diameter of the first conductor 12 and the second conductor 22. The Y-direction position was offset by 1/2 upwards. From FIG. 11, it can be confirmed that the electric field intensity distribution of the analysis result and the electric field intensity distribution measured by the electric field probe 1 substantially match each other. Therefore, the electric field probe 1 can measure the Z direction component of the electric field at a position away from the structure of the electric field probe 1 . That is, the electric field probe 1 can bring the electric field measurement position closer to the object to be measured, can measure the distribution of the substrate-parallel component of the electric field with high resolution, and can obtain the electric field distribution with high resolution.

According to this embodiment, the following effects can be obtained.

(1) Since the first conductor 12 and the second conductor 22 are provided outside the first conductor 11 and the second conductor 21, the +Y distance from the tip of the first conductor 12 and the second conductor 22 is half the diameter thereof. The electric field at a misdirected position can be measured as if there were a dipole element at that position. Therefore, by bringing the electric field probe 1 close to the object to be measured within a range where it does not come into contact with the object to be measured, it is possible to measure the electric field in the immediate vicinity of the object to be measured without contacting the object to be measured. is obtained.

(2) The Y-direction positions of the first conductor 11 and the second conductor 21 are equal to each other, and the Y-direction positions of the first conductor 12 and the second conductor 22 are equal to each other. It becomes possible to obtain the electric field distribution.

(3) Since the first conductor 11 is covered with the first conductor 12 and the second conductor 21 is covered with the second conductor 22, the first conductor 12 and the second conductor 22 serve as shields, and the influence of the external electric field can be reduced. can.

(4) Since the first conductor 12 and the second conductor 22 are in contact with each other, the first conductor 12 and the second conductor 22 are at the same potential, and the asymmetry due to the stray capacitance can be reduced.

(5) By controlling the probe scanning device 62 with the control device 61, the electric field probe 1 can be moved in two or three axial directions and stopped at a predetermined position. After the control is completed, the measuring device 63 measures the electric field value at the predetermined position through the electric field probe 1 . The electric field value measured by the measuring device 63 is output by the control device 61 in association with the measurement position. An electric field distribution can be obtained from this.

(Embodiments 2 and 3)
FIG. 12(A) is a schematic perspective view of the distal end portion of the electric field probe 2 according to Embodiment 2 of the present invention. FIG. 12B is a schematic perspective view of the distal end portion of the electric field probe 3 according to Embodiment 3 of the present invention. In the electric field probe 2 of Embodiment 2, compared with the electric field probe 1 of Embodiment 1, the tips of the first conductor 11 and the second conductor 21 It is different in that it protrudes in the +Y direction from (probe surface), but is identical in other respects. Compared with the electric field probe 1 of the first embodiment, the electric field probe of the third embodiment is such that the tips of the first conductor 11 and the second conductor 21 lie on the plane of existence of the tips of the first conductor 12 and the second conductor 22 ( It is different in that it is recessed in the -Y direction from the probe surface), and is identical in other respects.

FIG. 13A is an electric field intensity distribution diagram obtained by numerical analysis of the intensity distribution of the component in the direction perpendicular to the Y direction of the electric field generated by the electric field probe 2 when the electric field probe 2 is used as a transmitting antenna. FIG. 3 is an electric field intensity distribution diagram obtained by calculating the intensity distribution of the component in the direction perpendicular to the Y direction of the electric field generated by the electric field probe 3 when the electric field probe 3 is used as a transmitting antenna, calculated by numerical analysis. Comparison with the electric field intensity distribution (FIG. 5A) obtained by the electric field probe 1 in which the Y-direction positions of the tips of the first conductor 11 and the second conductor 21 match the Y-direction positions of the tips of the first conductor 12 and the second conductor 22 Then, the electric field strength distributions of the electric field probes 2 and 3 (FIGS. 13A and 13B) also showed similar results. From this result, the tips of the first conductor 11 and the second conductor 21 are recessed in the -Y direction from the plane (probe plane) where the tips of the first conductor 12 and the second conductor 22 exist, or the first conductor 11 and Even if the tip of the second conductor 21 protrudes in the +Y direction from the existing plane (probe plane) of the tips of the first conductor 12 and the second conductor 22, the protrusion length is half the diameter of the first conductor 12 and the second conductor 22. If it is within the range, the electric field in the immediate vicinity of the object can be measured without contacting the object, and the electric field can be measured with higher resolution.

(Embodiment 4)
FIG. 14 is a schematic configuration diagram of an electric field probe 4 according to Embodiment 4 of the present invention. From the description in Embodiment 1, if the probe structure is a symmetrical structure in the plane including the inner conductors (the first conductor 11 and the second conductor 21), the components other than the Z-direction component are canceled. The planar structure determines the properties of the probe. Therefore, in the following embodiments, the two-dimensional structure on the plane will be described. The XYZ axes, which are three orthogonal axes, are defined by FIG. The extending direction of the first conducting wire 11 and the second conducting wire 21 is the Y direction, the direction perpendicular to the Y direction and parallel to the plane on which the first conducting wire 11 and the second conducting wire 21 exist is the Z direction, and the direction perpendicular to the plane is It is the X direction. The electric field probe 4 has a first conductor 11 , a second conductor 21 , a first conductor 31 and a second conductor 32 .

The first conducting wire 11 and the second conducting wire 21 are parallel to each other. The first conductor 31 and the second conductor 32 are provided on a plane containing the first conductor 11 and the second conductor 21, are parallel to the first conductor 11 and the second conductor 21, and are grounded together. The first conductor 31 is located on the −Z direction side of the first conductor 11 . The second conductor 32 is positioned on the +Z direction side of the second conductor 21 . There is no conductor connecting the tips of the first conductor 31 and the second conductor 32 on the plane. A line segment 35 of length w connecting the tips of the first conductor 31 and the second conductor 32 is perpendicular to the first conductor 11 and the second conductor 21 . A straight line 39 connecting the tips of the first conducting wire 11 and the second conducting wire 21 is parallel to the line segment 35 . The distance d between the two intersections 36 and 37 of the line segment 35 and two perpendicular lines respectively drawn from the tips of the first conductor 31 and the second conductor 32 to the line segment 35 and the center 38 of the line segment 35 is are equal and 0<d<w/2. The distance h from the tips of the first conductor 11 and the second conductor 21 to the line segment 35 is 0≦h≦w/2−d. Alternatively, the tips of the first conducting wire 11 and the second conducting wire 21 do not intersect with the segment 35 (located on the -Y direction side of the tips of the first conductor 31 and the second conductor 32).

If the electric field probe 4 has a structure (a conductor or a dielectric) other than on the plane containing the first conductor 11 and the second conductor 21, the structure is symmetrical about the plane. The first conductor 31 and the second conductor 32 are a common conductor (for example, a cylindrical or elliptical cylindrical conductor) that covers the first conductor 11 and the second conductor 21 without contacting the first conductor 11 and the second conductor 21. may be part of The first conductor 31 may be part of a conductor that covers the first conductor 11 without contacting the first conductor 11 . The second conductor 32 may be part of a conductor that covers the second conductor 21 without contacting the second conductor 21 . According to the electric field probe 4 of the present embodiment, due to the presence of the first conductor 31 and the second conductor 32, the tip of the first conductor 31 and the second conductor 32 is shifted in the +Y direction by w/2-d. The electric field at the position can be measured in the same way as when there is a dipole element at that position, and a high-resolution electric field distribution can be obtained as in the first embodiment.

(Embodiments 5-7)
FIG. 15A is a schematic configuration diagram of an electric field probe according to Comparative Example 2. FIG. FIG. 15B is a schematic configuration diagram of an electric field probe 5 according to Embodiment 5 of the present invention. FIG. 15C is a schematic configuration diagram of an electric field probe 6 according to Embodiment 6 of the present invention. FIG. 15D is a schematic configuration diagram of an electric field probe 7 according to Embodiment 7 of the present invention. The analysis regions shown in FIGS. 15(A) to 15(D) represent the analysis regions of the electric field distribution in FIGS. 16(A) to 16(D). The electric field probe according to Comparative Example 2 is obtained by removing the first conductor 31 and the second conductor 32 from the electric field probe 4 according to the fourth embodiment. The electric field probe 5 according to the fifth embodiment is the same as the electric field probe 4 according to the fourth embodiment, except that h=0. The electric field probe 6 according to the sixth embodiment is obtained by adding a grounded third conductor 33 to the electric field probe 5 according to the fifth embodiment. The third conductor 33 is centrally located between the first conductor 11 and the second conductor 21 and parallel to the first conductor 31 and the second conductor 32 . The electric field probe 7 according to the seventh embodiment is obtained by extending the first conductor 11 of the electric field probe 6 according to the sixth embodiment in the +Y direction by a length within w/2-d in FIG.

FIGS. 16(A) to 16(D) show the distribution of the component of the electric field generated by the electric field probe in each configuration of FIGS. It is an electric field distribution map showing the result calculated by. Comparing FIG. 16(A) with FIGS. 16(B) to 16(D), it can be seen that the electric field distribution in FIGS. 16(B) to 16(D) is shifted in the +Y direction. That is, from this result, by adding the first conductor 31 and the second conductor 32 to the outside of the first conductor 11 and the second conductor 21 which are the separated two parallel differential lines, the electric field is pushed out in the +Y direction. be able to. 16(B) and 16(D), there is no significant difference in the electric field distribution at some distance from the electric field probe, and the difference in tip positions of the first conducting wire 11 and the second conducting wire 21 has little effect. Thus, the electric field probe of each embodiment utilizes the principle that the electric field is pushed out in the +Y direction by adding the first conductor 31 and the second conductor 32 to the outside of the first conductor 11 and the second conductor 21. , a high-resolution electric field distribution can be obtained.

Although the present invention has been described above with reference to the embodiments, it will be understood by those skilled in the art that various modifications can be made to each component and each processing process of the embodiments within the scope of the claims. By the way.

1 to 7 electric field probes,
10 first coaxial line (first coaxial cable), 11 first conductor (first inner conductor), 12 first conductor (first outer conductor), 13 first dielectric,
20 second coaxial line (second coaxial cable), 21 second conductor (second inner conductor), 22 second conductor (second outer conductor), 23 second dielectric,
31 first conductor, 32 second conductor, 33 third conductor, 35 line segment, 36, 37 intersection, 38 center, 39 straight line,
50 microstrip line, 51 dielectric substrate, 52 signal line, 53 ground pattern, 55 termination resistor, 57 input signal,
61 control device, 62 probe scanning device (probe scanning mechanism), 63 measuring instrument, 64 differential signal output circuit, 70 specimen,
81 inner conductor, 82 outer conductor, 85,86 coaxial cable

Claims (9)

first and second conductors parallel to each other;
first and second conductors parallel to the first and second conductors provided on a plane containing the first and second conductors;
there is no conductor connecting the ends of the first and second conductors on the plane parallel to the plane;
a line segment of length w connecting the tips of the first and second conductors on the plane is perpendicular to the first and second conductors;
distances d between two intersections of the line segment and two perpendicular lines drawn from the ends of the first and second conductors to the line segment and the center of the line segment are equal to each other, and 0<d <w/2,
each of the first and second conductors has a distance h from its tip to the line segment of 0≦h≦w/2−d, or does not intersect the line segment;
An electric field probe wherein the structure out of said plane is symmetrical about said plane. 2. The electric field probe of claim 1, wherein said first and second conductors are part of a common conductor covering said first and second conductors without contacting said first and second conductors. first and second conductors parallel to each other;
First to third conductors parallel to the first and second conductors provided on a plane containing the first and second conductors,
the third conductor is centrally located between the first and second conductors;
a line segment of length w connecting the tips of the first and second conductors on the plane is perpendicular to the first and second conductors;
distances d between two intersections of the line segment and two perpendicular lines drawn from the ends of the first and second conductors to the line segment and the center of the line segment are equal to each other, and 0<d <w/2,
each of the first and second conductors has a distance h from its tip to the line segment of 0≦h≦w/2−d, or does not intersect the line segment;
An electric field probe wherein the structure out of said plane is symmetrical about said plane. The first conductor is a part of a conductor that covers the first conductor without contacting the conductor,
The second conductor is a part of the conductor that covers the second conductor without contacting the conductor,
4. The electric field probe of claim 3, wherein said third conductor is a mutual contact of said conductor over said first conductor and said conductor over said second conductor. The electric field probe according to any one of claims 1 to 4, wherein the line segment and a straight line connecting the tips of the first and second conductors are parallel. first and second conductors parallel to each other;
a first conductor that covers the first conductor without contacting the conductor;
a second conductor that covers the second conductor without contacting the conductor,
outer peripheral surfaces of the first and second conductors are in contact with each other;
When the existence plane of the tips of the first and second conductors is the first plane,
whether the projection length of the tips of the first and second conductors from the first plane is within half the diameter of the first and second conductors;
whether the tips of the first and second conductors lie in the first plane;
whether the tips of the first and second conductors are recessed with respect to the first plane;
is either
An electric field probe that outputs a differential signal of signals received on the first and second conductors . The first conductor and the first conductor constitute a first coaxial line,
7. The electric field probe of claim 6, wherein said second conductor and said second conductor constitute a second coaxial line. first and second conductors parallel to each other;
a common conductor covering the first and second conductors without contacting the first and second conductors;
a line segment of length w connecting the tips of the common conductors on a plane containing the first and second conductors is perpendicular to the first and second conductors;
distances d between two intersections of the line segment and two perpendicular lines drawn from the ends of the first and second conductors to the line segment and the center of the line segment are equal to each other, and 0<d <w/2,
The electric field probe, wherein each of the first and second conductors has a distance h from its tip to the line segment that is 0≦h≦w/2−d, or does not intersect the line segment. An electric field probe according to any one of claims 1 to 8;
a probe scanning mechanism capable of moving the electric field probe in at least two of the three axial directions in space;
a controller that controls the probe scanning mechanism;
a measuring instrument capable of measuring an electric field value at a predetermined position through the electric field probe;
and an arithmetic unit that outputs the electric field value measured by the measuring instrument in correspondence with the measurement position.

Images