JP5371852B2 - Antenna measuring apparatus and antenna measuring method - Google Patents

Description

  The present invention relates to an antenna measurement device and an antenna measurement method.

  As an antenna measuring apparatus and an antenna measuring method related to the present invention, for example, there are an antenna measuring apparatus and an antenna measuring method described in Patent Document 1 and Patent Document 2 below. These conventional techniques are techniques for measuring an electric field (hereinafter referred to as element electric field) transmitted or received from each element antenna (hereinafter referred to as element) constituting the phased array antenna. In any document, a technique for measuring an element electric field for each phase shift state of a phase shifter that similarly constitutes a phased array antenna is disclosed.

  In the antenna measurement apparatus and the antenna measurement method described in Patent Document 1, the excitation phase of an arbitrary element constituting the phased array antenna is changed from 0 degrees to 360 degrees, and the amplitude and phase of the combined electric field of the array antenna at that time Measure changes. From this measurement result, the combined electric field of the array antenna excluding the element electric field of the element is obtained, and the element electric field in each phase shift state is obtained by taking the difference from the combined electric field of the array antenna of all the previous elements. .

  Further, in the antenna measurement apparatus and the antenna measurement method described in Patent Document 2, the excitation phase of an arbitrary element constituting the phased array antenna is changed from 0 degrees to 360 degrees, and the amplitude of the combined power of the array antenna at that time The change is taken as the measurement. Further, the above measurement procedure is repeated by changing the excitation phase of elements other than the element to be measured for the element electric field. The element electric field in each phase shift state of the element is estimated from a plurality of changes in the combined power of the array antenna obtained as described above.

Japanese Patent No. 3638108 International Publication No. WO2004 / 013644 Pamphlet Japanese Patent Publication No. 1-337882

Yonezawa Rumiko, Sato Junichi, Katagi Takashi, "Relation between phase shifter error and phased array excitation amplitude phase measurement error when using element electric field vector rotation method", IEICE, IEICE, A / P92 -75, pp.47-52, 1992

  In the antenna measurement apparatus and the antenna measurement method disclosed in Patent Document 1, not only the amplitude measurement of the array antenna combined electric field but also the phase measurement is necessary. Therefore, it has been difficult to apply the calibration to the phased array antenna in which phase measurement with high accuracy is difficult or the phased array antenna in the millimeter wave band and the submillimeter wave band in which phase measurement with high accuracy is difficult.

  Further, since the antenna measurement apparatus and the antenna measurement method of Patent Document 2 do not require phase measurement, the problem of Patent Document 1 is solved. However, it is necessary to measure the change of the array antenna combined power a plurality of times, which causes a problem that the number of times of measurement becomes very large and the measurement time becomes enormous. Further, the element electric field estimation method is not deterministic but based on numerical repetitive calculation, and there is a problem that the convergence of the solution is not clear.

  The present invention has been made to solve the above-described problem, and an antenna measurement apparatus that measures the element electric field in each phase shift state of the phase shifter only by measuring the amplitude of the combined power of the array antenna and shortens the measurement time. And an antenna measurement method.

  The present invention changes the excitation phase of a phased array antenna in which a phase shifter is connected to each of a plurality of element antennas and one element antenna to which attention is paid by controlling the passing phase of the phase shifter from 0 degrees to 360 degrees. A phase shifter control means, a measurement antenna unit installed at a predetermined position with respect to the phased array antenna, a transmitter connected to one of the phased array antenna and the measurement antenna unit, and transmitting a high frequency signal, A receiver connected to the other of the phased array antenna and the measurement antenna unit and measuring the received power while the phase shifter control means changes the excitation phase of the phase shifter, and the power change measured by the receiver The element electric field of the element antenna with the excitation phase changed is calculated from the average value of the signal and the Fourier coefficient of the fundamental wave component obtained by expanding the Fourier series. First arithmetic means that performs Fourier series expansion of the power change measured by the receiver to calculate a Fourier coefficient of a harmonic component, an element electric field of the first arithmetic means, and the second And third arithmetic means for estimating an element electric field in each phase shift state of the phase shifter of the element antenna, the excitation phase of which has been changed based on the Fourier coefficient of the harmonic component of the arithmetic means. An antenna measuring apparatus and an antenna measuring method are provided.

  According to the present invention, it is possible to provide an antenna measurement apparatus and an antenna measurement method in which the element electric field in each phase shift state of the phase shifter is measured only by measuring the amplitude of the combined power of the array antenna and the measurement time is shortened.

It is a figure which shows the structure of the antenna measuring device by Embodiment 1 of this invention. It is a figure which shows an example of the change of the array synthetic | combination power which a receiver detects when the excitation phase of an element antenna in this invention changes sequentially. It is a figure which shows the structure of the antenna measuring device by Embodiment 2 of this invention. It is a figure which shows the example of the element electric field amplitude error or element electric field phase error of each bit corresponding to the phase shift state in the case of the 4-bit digital phase shifter in this invention. It is a figure which shows the structure of the antenna measuring device by Embodiment 3 of this invention. It is a figure which shows the structure of the antenna measuring device by Embodiment 4 of this invention. It is a figure which shows the structure of the antenna measuring device by Embodiment 5 of this invention. It is a figure which shows an example of the element antenna structure of the antenna measuring device by Embodiment 6 of this invention. It is a figure which shows the structure of the antenna measuring device by Embodiment 7 of this invention.

  Hereinafter, an antenna measuring apparatus and an antenna measuring method according to the present invention will be described with reference to the drawings according to each embodiment. In each embodiment, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

Embodiment 1 FIG.
1 is a diagram showing the configuration of an antenna measurement apparatus according to Embodiment 1 of the present invention. In the figure, 1-1, 1-2,..., 1-M represent element antennas, and the number of element antennas here is M (M is a positive integer of 2 or more: plural). 2, 1-2,..., 2 -M are connected to the element antennas 1-1, 1-2,. For example, a 4-bit digital phase shifter is used. A power distribution circuit 3 distributes power to the element antennas 1-1, 1-2,. Reference numeral 4 denotes a phase shifter control circuit that controls the phase shift states of the digital phase shifters 2-1, 2-2,. Reference numeral 5 denotes a transmitter that transmits a high-frequency signal to the power distribution circuit 3.

  Therefore, the element antennas 1-1, 1-2,..., 1-M, the phase shifters 2-1, 2-2,. An antenna is formed. 6-a is a counter antenna constituting the measurement antenna unit installed at a position facing the element antennas 1-1, 1-2,..., 1-M, and 7 is received by the counter antenna 6-a. It is a receiver that receives the high frequency signal. Reference numeral 8 denotes an average value calculation circuit which is a means for calculating a change in received power of the receiver 7. Reference numeral 9 denotes a fundamental wave Fourier coefficient calculation circuit that calculates a Fourier sine coefficient and a Fourier cosine coefficient of a fundamental wave component by expanding the received power of the receiver 7 by Fourier series. Reference numeral 10 denotes a harmonic Fourier coefficient calculation circuit that calculates a Fourier sine coefficient and a Fourier cosine coefficient of a harmonic component by expanding a change in received power of the receiver 7 by Fourier series. Reference numeral 11 denotes an element electric field calculation circuit that calculates the amplitude and phase of an electric field (hereinafter, element electric field) radiated from the element antenna by an element electric field vector rotation method as described in Patent Document 3, for example. 12 is a digital phase shifter 2-by using the Fourier sine coefficient and Fourier cosine coefficient of the harmonic component calculated by the harmonic Fourier coefficient calculation circuit 10 and the amplitude and phase of the element electric field calculated by the element electric field calculation circuit 11. 1 is an element electric field error estimation circuit that estimates an element electric field error in each of the phase shift states of 1, 2-2,.

  Next, the operation of the antenna measuring apparatus according to the present invention will be described. The high frequency signal transmitted from the transmitter 5 is input to the power distribution circuit 3 and then distributed. The distributed high-frequency signal is given a predetermined phase change amount according to the phase shift state of the digital phase shifter by the digital phase shifters 2-1, 2-2,. Radiated into space from the antennas 1-1, 1-2,. The high-frequency signal radiated to the space is combined again in the space and received by the opposing antenna 6-a. The combined power (hereinafter referred to as array combined power) received by the counter antenna 6-a is detected by the receiver 7.

  Here, the phase shifter control circuit 4 sets the phase shift state of the digital phase shifter connected to any of the element antennas 1-1, 1-2,. From 360 to 360 degrees. The phase shift states of the digital phase shifters of the other element antennas are constant or the same constant. If this arbitrarily focused element antenna is an element antenna 1-m, and a digital phase shifter connected to the element antenna and sequentially changes the phase shift state from 0 degrees to 360 degrees is a digital phase shifter 2-m, Since the phase shifter control circuit 4 sequentially changes the excitation phase of the element antenna 1-m from 0 degrees to 360 degrees, the change in the array combined power detected by the receiver 7 at this time is, for example, as shown in FIG. become.

  In FIG. 2, the horizontal axis represents the amount of change in the excitation phase of the element antenna 1-m, that is, the phase shift state of the digital phase shifter 2-m, and the vertical axis represents the array combined power detected by the receiver 7. In FIG. 2, reference numeral 13 denotes a change in the array combined power corresponding to the amount of change in the excitation phase of the element antenna 1-m. This change is substantially a cosine change (hereinafter referred to as Patent Document 3). , Cosine curve).

  Next, the average value calculation circuit 8 calculates the average value of the cosine curve, and the fundamental wave Fourier coefficient calculation circuit 9 expands the cosine curve by Fourier series to calculate the Fourier sine coefficient and the Fourier cosine coefficient of the fundamental wave component. . Further, the element electric field calculation circuit 11 uses the average value of the array combined power calculated by the average value calculation circuit 8 and the Fourier sine coefficient and Fourier cosine coefficient of the fundamental wave component calculated by the fundamental wave Fourier coefficient calculation circuit 9. The measured values of the amplitude and phase of the element electric field of the element antenna 1-m are calculated by the arithmetic expression of the element electric field vector rotation method as described in Patent Document 3 and Non-Patent Document 1.

  The element electric field measured value obtained by the element electric field calculation circuit 11 is an element which is regarded as having no error in the passing amplitude and passing phase of the digital phase shifter in each phase shift state of the digital phase shifter 2-m. Electric field. However, digital phase shifters generally have different pass amplitude errors and pass phase errors for each phase shift state. For this reason, the element electric field in each phase shift state of the digital phase shifter 2-m is different from the value obtained by giving the phase change amount of the phase shift state to the element electric field measurement value obtained by the element electric field calculation circuit 11. It becomes. The element electric field error estimation circuit 12 estimates an error between the element electric field in each phase shift state and the element electric field measurement value obtained by the element electric field calculation circuit 11, and calculates the true value of the element electric field in each phase shift state. Circuit. The calculation procedure of the element electric field error estimation circuit 12 is shown below.

If the amplitude of the element field measurements of antenna elements 1-m determined by the element field operation circuit 11 k _m, the phase and X _m, the element field amplitude in each phase state is given by the following formula (1) The element electric field phase is given by the following formula (2).

Here, i is a number representing the phase shift state of the digital phase shifter 2-m, and the element electric field amplitude corresponding to this phase shift state is km _{, i} , and the element electric field phase is _{Xm, i} . N is the maximum number for changing the excitation phase for one element. When an Nb bit digital phase shifter is used, N is expressed by the following equation (3).

In this embodiment, since each phase shifter is, for example, a 4-bit digital phase shifter, N = 16. The second term on the right side of the above equation (1) represents the element electric field amplitude error in each phase shift state. The second term on the right side of the above equation (2) is the amount of phase change to be given by the digital phase shifter in the i-th phase shift state, and the third term on the right side of the above equation (2) is the element electric field in each phase shift state. It represents the phase error. As can be seen from the above equations (1) and (2), the element electric field amplitude error and the element electric field phase error in each phase shift state are expressed in the form of discrete Fourier series expansion. The coefficients AC _l , AS _l , PC _l , PS _l (l = 0,..., N / 2) are unknown coefficients. However, AS ₀ = 0, PS ₀ = 0, AS _{N / 2} = 0, and PS _{N / 2} = 0 because of the nature of the discrete Fourier series expansion.

  When the element electric field amplitude and the element electric field phase in the i-th phase shift state of the digital phase shifter are expressed by the above equations (1) and (2), respectively, the array combined power in the phase shift state is expressed by the following equation (1) 4)

Here, f _{0, i} is the array combined power when there is no error in the element electric field amplitude and phase, that is, when the second term on the right side of the equation (1) and the third term on the right side of the equation (2) are zero. Represents. From the above equation (4), it can be seen that the array combined power is expressed in the form of Fourier series expansion including higher order terms.

  Incidentally, the average value calculation circuit 8 calculates the average value of the cosine curve as shown in FIG. 2, for example. Further, the fundamental wave Fourier coefficient calculation circuit 9 expands a cosine curve as shown in FIG. 2, for example, by Fourier series expansion, and calculates a Fourier sine coefficient and a Fourier cosine coefficient of the fundamental wave component. Further, the harmonic Fourier coefficient calculation circuit 10 expands a cosine curve such as that shown in FIG. 2 for example, and calculates a Fourier sine coefficient and a Fourier cosine coefficient of the harmonic component. Therefore, using the average value, Fourier sine coefficient, and Fourier cosine coefficient calculated by these circuits, the array combined power in the i-th phase shift state of the digital phase shifter is expressed by the following equation (5). .

Here, a _l (l = 0,..., N / 2) is a Fourier cosine coefficient, and b _l (l = 0,..., N / 2) is a Fourier sine coefficient. The term of l = 0 corresponds to the average value calculated by the average value calculation circuit 8, and the term of l = 1 is the Fourier sine coefficient and Fourier cosine coefficient of the fundamental wave component calculated by the fundamental wave Fourier coefficient calculation circuit 9. Correspond. The terms l = 2,..., N / 2 correspond to the Fourier sine coefficient and Fourier cosine coefficient of the harmonic component calculated by the harmonic Fourier coefficient calculation circuit 10.

When the above equations (4) and (5) are made to correspond, the unknown coefficients AC _l , AS _l , PC _l , PS _l (l = 0,..., N / 2, where AS ₀ = 0, PS ₀ = Simultaneous equations for 0, AS _{N / 2} = 0, PS _{N / 2} = 0) can be obtained. However, it is necessary to consider that the terms of l = 0 and l = 1 correspond to f _{0, i} in the above formula (4). As a result, unknown coefficients AC _l , AS _l , PC _l , PS _l (l = 0,..., N / 2, where AS ₀ = 0, PS ₀ = 0, AS _{N / 2} = 0, PS _N The simultaneous equations of the equation (13) are obtained from the following equation (6) with respect to _{/ 2} = 0).

Element field error estimation circuit 12, the Fourier cosine coefficients is calculated and the element field amplitude k _m and the element field phase X _m obtained by the element field operation circuit 11, the harmonic Fourier coefficient calculating circuit 10 a _{l (l} = 2 ,..., N / 2) and Fourier sine coefficient b _l (l = 2,..., N / 2), the unknown coefficient AC is solved by solving the simultaneous equations of the above equations (6) to (13). _l , AS _l , PC _l , PS _l (l = 0,..., N / 2, where AS ₀ = 0, PS ₀ = 0, AS _{N / 2} = 0, PS _{N / 2} = 0) calculate. However, since the number of simultaneous equations is N and the number of unknowns is 2N, an unknown coefficient is calculated using an optimization method such as a steepest descent method, a conjugate gradient method, or a linear programming method. To calculate. Unknown coefficients AC _l , AS _l , PC _l , PS _l (l = 0,..., N / 2, where AS ₀ = 0, PS ₀ = 0, AS _{N / 2} = 0, PS _{N / 2} = If (0) can be calculated, the element electric field amplitude and the element electric field phase in each phase shift state can be obtained from the above equations (1) and (2).

  The measurement procedure and the calculation procedure have been described for the element antenna 1-m. However, the same procedure is sequentially repeated for all the elements, whereby all the element antennas 1-1, 1-2,. The element electric field amplitude and element electric field phase in each phase shift state of 1-M can be obtained.

  From the above, this embodiment has an effect that the element electric field amplitude and the element electric field phase in each phase shift state of the phase shifter can be measured by the amplitude measurement without measuring the phase of the array combined power. In addition, the measurement procedure is the same as that of Patent Document 3 above, and the element electric field amplitude and element electric field phase in each phase shift state can be measured by the arithmetic processing after the measurement. There is an effect that the measurement time can be shortened compared to the apparatus.

Embodiment 2. FIG.
FIG. 3 is a diagram showing a configuration of an antenna measurement apparatus according to Embodiment 2 of the present invention. In the figure, reference numeral 14 denotes a phase shifter bit error calculation circuit that calculates an element electric field amplitude error and an element electric field phase error for each bit of the digital phase shifters 2-1 to 2 -M. 15 is an element that calculates the element electric field amplitude and the element electric field phase in each phase shift state based on the element electric field amplitude error and the element electric field phase error for each bit of the digital phase shifter calculated by the phase shifter bit error calculation circuit 14. It is an electric field error calculation circuit.

  In this embodiment, the phase shifter bit error calculation circuit 14 includes the Fourier sine coefficient and Fourier cosine coefficient of the harmonic component calculated by the harmonic Fourier coefficient calculation circuit 10, and the element electric field calculated by the element electric field calculation circuit 11. The element electric field error for each bit of the digital phase shifters 2-1 to 2-M is calculated using the amplitude and the phase. The calculation procedure will be described below.

  The digital phase shifters 2-1 to 2-M realize a phase shift state of 0 degrees to 360 degrees by combining phase change amounts corresponding to the respective bits. For example, in the case of a 4-bit digital phase shifter, the phase change amounts of bits 1, 2, 3, and 4 correspond to phase changes of 180 degrees, 90 degrees, 45 degrees, and 22.5 degrees, respectively. By combining these, a phase shift state of 0 degree to 360 degrees is realized. Therefore, the element electric field amplitude error and the element electric field phase error in each phase shift state can also be expressed by a combination of the amplitude error and the phase error for each bit.

  For example, in the case of the 4-bit digital phase shifter, the element electric field amplitude error or element electric field phase error of each bit corresponding to the phase shift state is as shown in FIG. In FIG. 4, the horizontal axis represents the phase shift state of the digital phase shifter, which is 0 degree to 360 degrees. The vertical axis represents the element electric field amplitude error or element electric field phase error for each bit corresponding to each phase shift state, and 16-a, 16-b, 16-c, 16-d are bits 1, 2, 3, respectively. 4 represents an element electric field amplitude error or an element electric field phase error. Accordingly, the element electric field amplitude error or the element electric field phase error as a digital phase shifter corresponding to each phase shift state is a value obtained by adding 16-a, 16-b, 16-c, and 16-d.

  Therefore, the element electric field amplitude error expressed as shown in FIG. 4 is expanded by Fourier series to correspond to the element electric field amplitude error for each bit and the element electric field amplitude error of the second term on the right side of the above equation (1). be able to. Similarly, the element electric field phase error represented as shown in FIG. 4 is expanded by Fourier series to correspond to the element electric field phase error for each bit and the element electric field phase error of the third term on the right side of the above equation (2). be able to.

Due to this Fourier series expansion, the p-th bit element electric field amplitude error is DA _p (p = 1,..., Nb), and the element electric field phase error is DP _p (p = 1,..., Nb). Then, the unknown coefficients AC _l , AS _l , PC _l , PS _l (l = 0,..., N / 2 in the first embodiment, where AS ₀ = 0, PS ₀ = 0, AS _N Equation (17) can be derived from the following Equation (14) as a relational expression with _{/ 2} = 0, PS _{N / 2} = 0).

  However, l is an integer which has the relationship of p and following formula (18).

By substituting the above equations (14) to (17) into the simultaneous equations of equations (6) to (13), unknown variables DA _p (p = 1,..., Nb), DP _p (p = 1,..., Nb) can be obtained. The unknown coefficients are AC _l , AS _l , PC _l , PS _l (l = 0,..., N / 2, where AS ₀ = 0, PS ₀ = 0, AS _{N / 2} = 0, PS _{N / 2.} = 0), the number of variables is 2N, while the unknown variables are DA _p (p = 1,..., Nb) and DP _p (p = 1,..., Nb). The number of variables in the case is 2Nb. On the other hand, the number of simultaneous equations is N. Therefore, when a digital phase shifter of 3 bits or more is used, the number of equations becomes greater than or equal to the unknown, and the unknown can be uniquely determined.

As mentioned above algorithm, the phase shifter bit error calculating circuit 14, an element field amplitude k _m and the element field phase X _m obtained by the element field operation circuit 11, the harmonic Fourier coefficient calculation circuit 10 From the calculated Fourier cosine coefficient a _l (l = 2,..., N / 2) and Fourier sine coefficient b _l (l = 2,..., N / 2), the equations (6) to (13 ) And Eq. (14) to solve the simultaneous equations of Eq. (17) to uniquely identify unknown variables DA _p (p = 1,..., Nb) and DP _p (p = 1,..., Nb). calculate.

Next, the element field error calculating circuit 15, the element field amplitude error of each bit of the digital phase shifter phase shifter bit error calculating circuit 14 calculates _{DA p (p = 1, ···} , Nb) and device field By means of the phase error DP _p (p = 1,..., Nb), the element electric field amplitude and the element electric field phase in each phase shift state are expressed by the equations (1), (2), and (14) to (17). ) To calculate.

  From the above, this embodiment has an effect that the element electric field amplitude and the element electric field phase in each phase shift state of the phase shifter can be measured by the amplitude measurement without measuring the phase of the array combined power. In addition, the measurement procedure is the same as that of Patent Document 3 above, and the element electric field amplitude and element electric field phase in each phase shift state can be measured by the arithmetic processing after the measurement. There is an effect that the measurement time can be shortened compared to the apparatus. Further, there is an effect that the element electric field amplitude and the element electric field phase in each phase shift state can be uniquely determined.

Embodiment 3 FIG.
FIG. 5 is a diagram showing a configuration of an antenna measurement apparatus according to Embodiment 3 of the present invention. In the figure, 6-b and 6-c are second and third opposing antennas, respectively. Reference numeral 17 denotes a power combining circuit that combines signals received by the opposing antennas 6-a, 6-b, and 6-c. Thus, in this embodiment, an array antenna (measurement antenna unit) is formed by the opposing antennas 6-a, 6-b, 6-c and the power combining circuit 17. Therefore, the signal-to-noise (S / N) ratio of the received signal can be improved.

  From the above, in this embodiment, in addition to the effect described in the second embodiment, since the signal-to-noise ratio of the received signal can be improved, the measurement accuracy is improved.

Embodiment 4 FIG.
FIG. 6 is a diagram showing a configuration of an antenna measurement apparatus according to Embodiment 4 of the present invention. In this embodiment, the opposing antennas 6-a to 6-d are installed on the same opening surface as the element antennas 1-1 to 1-M.

  From the above, in this embodiment, in addition to the effects described in the third embodiment, there is an effect of realizing downsizing of the antenna measuring apparatus.

Embodiment 5 FIG.
FIG. 7 is a diagram showing the configuration of an antenna measurement apparatus according to Embodiment 5 of the present invention. In the figure, reference numeral 18 denotes a phase shift state selection circuit that selects a desired phase shift state using information on the element electric field amplitude and element electric field phase in each phase shift state calculated by the element electric field error calculation circuit 15.

  In this embodiment, the phase shift state selection circuit 18 has a phase shift state in which the element electric field phase of each element antenna 1-m represented by the above formula (2) is substantially in phase or in phase with all element antennas. Ask. Next, the phase shift state selected by the phase shift state selection circuit 18 is input to the phase shifter control circuit 4, and this is set in each of the phase shifters 2-1 to 2-M. Thereby, the signals transmitted from the element antennas 1-1 to 1-M can be substantially in phase or in phase.

  From the above, in this embodiment, in addition to the effect described in the second embodiment, there is an effect that the gain of the phased array antenna can be maximized.

  In the above description, the example in which this embodiment is applied to the configuration of the antenna measurement apparatus (method) of Embodiments 2 to 4 shown in FIGS. 3, 5, and 6 has been described. However, the embodiment shown in FIG. In this case, the phase shift state selection circuit 18 can be applied to the element electric field amplitude and element in each phase shift state calculated by the element electric field error estimation circuit 12 in FIG. Similar processing is performed using the information on the electric field phase, and a corresponding effect is obtained.

Embodiment 6 FIG.
FIG. 8 is a diagram showing an example of an element antenna configuration of an antenna measurement apparatus according to Embodiment 6 of the present invention. In the figure, reference numeral 19 denotes an antenna aperture outline, and 1-m denotes an element antenna. 21-a is an element antenna group on the left side with respect to the central axis of the antenna opening, and 21-b is an element antenna group on the right side.

In this embodiment, the above-described phase shift state selection circuit 18 uses the information on the element electric field amplitude and the element electric field phase in each phase shift state calculated by the element electric field error calculation circuit 15 to use the element antenna group 21-a. The phase shift state where the phase difference between the element antennas in the element antenna group 21-b and the element antennas of the element antenna group 21-b is approximately 180 degrees or 180 degrees and the sum of all the element electric fields is approximately zero or zero is defined as each element antenna 1- Select independently for M. Here, the element electric field at the time of obtaining the sum of the element electric fields is a complex value. For example, the element electric field amplitude km _{, i of} the element antenna 1-m represented by the above expressions (1) and (2), When the element electric field phase X _{m, i} is used, it is expressed by the following formula (19).

  Next, the phase shift state selected as described above is input to the phase shifter control circuit 4, and this is set in each of the phase shifters 2-1, 2-2,. Thereby, a difference pattern having a deep null point can be formed.

  From the above, in this embodiment, in addition to the effect described in the second embodiment, there is an effect that a differential pattern having a deep null point can be formed in the phased array antenna.

  Note that this embodiment is applicable not only to the configuration of the antenna measurement apparatus (method) of Embodiments 2 to 4 but also to the configuration of the antenna measurement apparatus (method) of Embodiment 1 and corresponding effects. Is obtained.

Embodiment 7 FIG.
FIG. 9 is a diagram showing a configuration of an antenna measurement apparatus according to Embodiment 7 of the present invention. In the antenna device configuration shown in the figure, the transmitter 5 is connected to the opposing antenna 6-a that constitutes the measurement antenna unit, and the receiver 7 is connected to the power distribution circuit 3 on the phased array antenna side. It has a configuration in which transmission and reception of the antenna measurement device are interchanged.

  From the above, this embodiment has the same effects as those of the second embodiment.

  The present invention is not limited to the above-described embodiments, and it goes without saying that all possible combinations thereof are included.

  1-1 to 1-M element antenna, 2-1 to 2-M phase shifter (digital phase shifter), 3 power distribution circuit, 4 phase shifter control circuit, 5 transmitter, 6-a to 6-c Counter antenna, 7 Receiver, 8 Average value arithmetic circuit, 9 Fundamental Fourier coefficient arithmetic circuit, 10 Harmonic Fourier coefficient arithmetic circuit, 11 Element electric field arithmetic circuit, 12 Element electric field error estimation circuit, 14 Phase shifter bit error arithmetic circuit , 15 element electric field error calculation circuit, 17 power combining circuit, 18 phase shift state selection circuit, 21-a, 21-b element antenna group.

Claims (14)

A phased array antenna in which a phase shifter is connected to each of a plurality of element antennas;
Phase shifter control means for controlling the passing phase of the phase shifter and changing the excitation phase of one element antenna of interest from 0 degrees to 360 degrees;
A measurement antenna unit installed at a predetermined position with respect to the phased array antenna;
A transmitter connected to one of the phased array antenna and the measurement antenna unit to transmit a high-frequency signal;
A receiver connected to the other of the phased array antenna and the measurement antenna unit for measuring received power while the phase shifter control means is changing the excitation phase of the phase shifter;
A first calculation means for calculating an element electric field of an element antenna having an excitation phase changed from an average value of power change measured by the receiver and a Fourier coefficient of a fundamental wave component obtained by Fourier series expansion;
A second computing means for calculating a Fourier coefficient of a harmonic component by expanding a Fourier series of a power change measured by the receiver;
The element electric field in each phase shift state of the phase shifter of the element antenna with the excitation phase changed based on the element electric field of the first calculation means and the Fourier coefficient of the harmonic component of the second calculation means is estimated. Third computing means for
An antenna measuring device comprising:   The antenna measurement apparatus according to claim 1, wherein the phase shifter is a digital phase shifter.   The third calculation means calculates a pass amplitude phase error of each bit of the digital phase shifter based on the element electric field of the first calculation means and the Fourier coefficient of the harmonic component of the second calculation means. Phase shifter bit error calculation means; and element electric field error calculation means for calculating an element electric field in each phase shift state from a pass amplitude phase error for each bit calculated by the phase shifter bit error calculation means. The antenna measurement device according to claim 2.   Phase state selection that causes the phase shifter control means to control each phase shifter so that the element electric field becomes substantially in phase based on the element electric field in each phase shift state estimated by the third arithmetic means. The antenna measurement apparatus according to claim 1, further comprising means.   The phase shift state of the left and right element antennas with respect to the center axis of the aperture of the phased array antenna is inverted by approximately 180 degrees, and the sum of the element electric fields estimated by the third calculation means is approximately zero. The antenna measurement apparatus according to any one of claims 1 to 3, further comprising phase state selection means for causing the phase shifter control means to control the phase shifter so as to be in a state.   The antenna measurement apparatus according to claim 1, wherein the measurement antenna unit includes an array antenna including a plurality of element antennas.   The antenna measurement apparatus according to claim 1, wherein the measurement antenna unit is installed on the same plane as the opening of the phased array antenna. A phased array antenna in which a phase shifter is connected to each of a plurality of element antennas, and a phase shifter that controls the passing phase of the phase shifter and changes the excitation phase of one element antenna of interest from 0 degrees to 360 degrees A control means; a measurement antenna unit installed at a predetermined position with respect to the phased array antenna; a transmitter connected to one of the phased array antenna and the measurement antenna unit; and a phased array antenna; A receiver connected to the other of the measurement antenna unit and measuring the received power while the phase shifter control means is changing the excitation phase of the phase shifter; and
A first step of calculating an element electric field of an element antenna having an excitation phase changed from an average value of power changes measured by the receiver and a Fourier coefficient of a fundamental wave component obtained by Fourier series expansion;
A second step of calculating a Fourier coefficient of a harmonic component by expanding a Fourier series of the power change measured by the receiver;
Estimating the element electric field in each phase shift state of the phase shifter of the element antenna with the excitation phase changed based on the element electric field of the first step and the Fourier coefficient of the harmonic component of the second step; And the process of
An antenna measurement method comprising:   9. The antenna measurement method according to claim 8, wherein a digital phase shifter is used as the phase shifter.   A phase shifter bit in which the third step calculates a pass amplitude phase error of each bit of the digital phase shifter based on the Fourier coefficient of the element electric field of the first step and the harmonic component of the second step. An error calculation step, and an element electric field error calculation step of calculating an element electric field in each phase shift state from a pass amplitude phase error for each bit calculated by the phase shifter bit error calculation means. Item 10. The antenna measurement method according to Item 9.   Phase state selection step of controlling each phase shifter by the phase shifter control means so that the element electric field becomes substantially in phase based on the element electric field in each phase shift state estimated in the third step. The antenna measurement method according to claim 8, further comprising:   The phase shift state of the left and right element antennas with respect to the center axis of the aperture of the phased array antenna is inverted by approximately 180 degrees, and the sum of the element electric fields estimated by the third calculation means is approximately zero. The antenna measurement method according to any one of claims 8 to 10, further comprising a phase state selection step of controlling each phase shifter by the phase shifter control means so as to be in a state.   The antenna measurement method according to claim 8, wherein an array antenna including a plurality of element antennas is used as the measurement antenna unit.   The antenna measurement method according to claim 8, wherein the measurement antenna unit is installed on the same plane as the opening of the phased array antenna.

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