JP2012117959A - Antenna measurement device and antenna measurement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna measurement method and an antenna measurement device that can simplify measurement of an elementary electric field of a phased array antenna.SOLUTION: The antenna measurement method includes: a high frequency signal generation step for generating high frequency signals; an amplitude phase change step for changing an amplitude and a phase of the high frequency signal corresponding to an element antenna to be a measurement object by relating the amplitude and the phase to each other, of the high frequency signals generated in the high frequency signal generation step; a high frequency signal radiation step for radiating the high frequency signals including the high frequency signal having the amplitude and the phase changed in the amplitude phase change step from a plurality of element antennas corresponding to the respective high frequency signals; a high frequency signal reception step for receiving the radiated high frequency signals by an antenna for measurement; and an elementary electric field calculation step for calculating the elementary electric field of the element antenna to be the measurement object based on the high frequency signals received in the high frequency signal reception step.

Description

  The present invention relates to an antenna device and an antenna measurement method for measuring an electric field (hereinafter abbreviated as an element electric field) of a high-frequency signal transmitted or received from an element antenna (hereinafter abbreviated as an element as appropriate) that constitutes a phased array antenna. About.

  As an antenna measurement method for measuring the amplitude and phase of the element electric field of each element antenna constituting the phased array antenna, the excitation phase of any one element constituting the phased array antenna is changed from 0 degrees to 360 degrees, There is a method of measuring a change in the amplitude of the combined power of the array antenna (hereinafter abbreviated as array combined power) and processing the obtained measurement result (see, for example, Patent Document 1). According to this measurement method, a simple method of measuring the combined power level by changing the variable phase shifter of the element antenna to be measured using the property that the amplitude change of the array combined power is cosine-like, The amplitude and phase of the element electric field of the element to be measured can be calculated.

Japanese Patent Laid-Open No. 1-37882 (pages 2 to 4, FIG. 2)

  However, the antenna measurement method described in Patent Document 1 has a problem that the measurement is complicated from the following points. First, in order to measure the element electric field of one element, it is necessary to change the excitation phase of the element to be measured from 0 degrees to 360 degrees, which requires a lot of measurement time. For example, if a 5-bit digital phase shifter is used as a means for changing the excitation phase, there are 32 phase shift states, and therefore it is necessary to measure array combined power 32 times per element.

  Secondly, in the antenna measurement method described in Patent Document 1, two sets of solutions exist as measured values of each element electric field as described in Patent Document 1, and thus a process for selecting an appropriate solution is required. Become. In Patent Document 1, a plurality of determination methods for the selection are disclosed, but prior information for determination is necessary or re-measurement is required.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an antenna measurement method and an antenna measurement apparatus that can simplify the measurement of the element electric field of a phased array antenna.

  An antenna measurement method according to the present invention is an antenna measurement method for measuring an element electric field of an element antenna to be measured among a plurality of element antennas constituting a phased array antenna, wherein a high frequency signal generation step for generating a high frequency signal Of the high-frequency signal generated in the high-frequency signal generation step, the amplitude phase change step for changing the amplitude and phase of the high-frequency signal corresponding to the element antenna to be measured in association with each other, and the high-frequency signal generation step A high-frequency signal radiating step for radiating a high-frequency signal including a high-frequency signal whose amplitude and phase are changed in the amplitude phase changing step from a plurality of corresponding element antennas, and a plurality of elements in the high-frequency signal radiating step High frequency signal radiated from antenna Comprises a high frequency signal receiving step of receiving the measurement antenna, based on the radio frequency signal received by the radio frequency signal receiving step, an element field calculating step of calculating the element field of element antennas to be measured, a.

  An antenna measurement method according to the present invention is an antenna measurement method for measuring an element electric field of an element antenna to be measured among a plurality of element antennas constituting a phased array antenna, the high-frequency signal generating a high-frequency signal Generating step, high-frequency signal radiating step for radiating the high-frequency signal generated in the high-frequency signal generating step from the antenna for measurement, and high-frequency signal for receiving the high-frequency signal radiated in the high-frequency signal radiating step with a plurality of element antennas A reception step, an amplitude phase changing step for changing the amplitude and phase of the high frequency signal received by the element antenna to be measured among the high frequency signals received in the reception step, and a plurality of corresponding steps in the high frequency signal receiving step High-frequency signal received by element antenna A high frequency signal synthesis step for synthesizing a high frequency signal including a high frequency signal whose amplitude and phase are changed in the amplitude phase control step, and an element of the element antenna to be measured based on the high frequency signal synthesized in the high frequency signal synthesis step An element electric field calculation step for calculating an electric field.

  An antenna measuring apparatus according to the present invention is an antenna measuring apparatus that measures an element electric field of an element antenna to be measured among a plurality of element antennas constituting a phased array antenna, and generates a high-frequency signal. Amplitude phase change that changes the amplitude and phase of the high-frequency signal radiated from the element antenna to be measured among the high-frequency signals generated by the generation means and the high-frequency signal generation means and radiated from the plurality of element antennas Means, a measurement antenna for receiving high-frequency signals radiated from a plurality of element antennas, and an element electric field calculation means for calculating the element electric field of the element antenna to be measured based on the high-frequency signals received by the measurement antenna .

  An antenna measuring apparatus according to the present invention is an antenna measuring apparatus that measures an element electric field of an element antenna to be measured among a plurality of element antennas constituting a phased array antenna, and generates a high-frequency signal. Generating means, a measurement antenna that radiates a high-frequency signal generated by the high-frequency signal generating means, and a high-frequency signal that is radiated by the measurement antenna and received by a plurality of element antennas, received by the element antenna to be measured Amplitude phase changing means for changing the amplitude and phase of the received high-frequency signal in association with each other, and a high-frequency signal received by a plurality of element antennas, the amplitude and phase of which are changed by the amplitude phase changing means The high frequency signal synthesis means for synthesizing the high frequency signal and the high frequency signal synthesis means Based on the frequency signal, and a device field calculating means for calculating an element field of element antennas to be measured.

  According to the present invention, the measurement of the element electric field of the phased array antenna can be simplified.

It is a block diagram of the antenna measuring apparatus shown in Embodiment 1 of this invention. It is a flowchart showing the process of the antenna measuring method shown in Embodiment 1 in this invention. It is a graph showing the change of the excitation amplitude of the antenna measuring apparatus shown in Embodiment 1 in this invention. It is a graph showing the change of the excitation phase of the antenna measuring apparatus shown in Embodiment 1 in this invention. It is a graph showing the change of the array synthetic | combination power of the antenna measuring apparatus shown in Embodiment 1 in this invention. It is a graph showing the measurement result of the element electric field amplitude shown in Embodiment 1 of this invention. It is a graph showing the measurement result of the element electric field phase shown to Embodiment 1 in this invention. It is a block diagram of the antenna measuring apparatus shown in Embodiment 1 of this invention. It is a graph showing the change of the excitation amplitude of the antenna measuring apparatus shown in Embodiment 2 of this invention. It is a graph showing the change of the excitation phase of the antenna measuring apparatus shown in Embodiment 2 of this invention. It is a block diagram of the antenna measuring apparatus which concerns on Embodiment 3 of this invention. It is a graph showing the change of the excitation amplitude of the antenna measuring apparatus shown in Embodiment 3 of this invention. It is a graph showing the change of the excitation phase of the antenna measuring apparatus shown in Embodiment 3 of this invention. It is a graph showing the change of the array synthetic | combination power of the antenna measuring apparatus shown in Embodiment 3 of this invention. It is a graph showing the measurement result of the element electric field amplitude shown in Embodiment 3 of this invention. It is a graph showing the measurement result of the element electric field phase shown in Embodiment 3 of this invention. It is a block diagram of the antenna measuring apparatus shown in Embodiment 4 of this invention. It is a block diagram of the antenna measuring apparatus shown in Embodiment 5 of this invention. It is a block diagram of the antenna measuring apparatus shown in Embodiment 6 of this invention.

Embodiment 1 FIG.
An antenna measurement apparatus according to Embodiment 1 will be described with reference to FIGS. First, an antenna measurement apparatus in the case where a high frequency signal is transmitted from the test antenna side and received by the measurement antenna, that is, when the test antenna operates as a transmission antenna will be described. FIG. 1 shows a configuration diagram of an antenna measurement apparatus including a test antenna according to Embodiment 1 of the present invention. In FIG. 1, a test antenna is a phased array antenna composed of a plurality of element antennas including an element antenna to be measured, element antennas 1-1, 1-2, ..., 1-M, variable attenuators. , 2-M, digital phase shifters 3-1, 3-2,..., 3-M, and a power distribution and synthesis circuit 4. Here, M is the number of elements of the phased array antenna. The element antennas 1-1, 1-2,..., 1-M may be any type of antenna, such as a patch antenna or a horn antenna. The variable attenuators 2-1, 2-2, ..., 2-M are connected to the element antennas 1-1, 1-2, ..., 1-M, respectively, and change the excitation amplitude of the corresponding element antennas. . The digital phase shifters 3-1, 3-2, ..., 3-M are connected to the element antennas 1-1, 1-2, ..., 1-M, and change the excitation phase of the corresponding element antennas. . Here, for example, a 5-bit digital phase shifter is used. The power distribution / combination circuit 4 distributes the input high-frequency signal according to the number of elements, and supplies it to the corresponding element antennas 1-1, 1-2,..., 1-M (to which the distributed high-frequency signal is radiated). In contrast, power is supplied.

The variable attenuator control circuit 5 controls the attenuation amount, that is, the amplitude of each variable attenuator 2-1, 2-2, ..., 2-M, and the phase shifter control circuit 6 is a digital phase shifter 3-1, 3,..., 3-M control the phase shift state. The amplitude phase control command circuit 7 includes element antennas 1-1, 1-2,.
Control is performed in association with the excitation amplitude and excitation phase of any one element of M, that is, the variable attenuator control circuit 5 and the phase shifter control circuit 6 are operated synchronously. The transmitter 8 transmits a high frequency signal to the power distribution and synthesis circuit 4.

  The measurement antenna 9-a is installed at a position facing the element antennas 1-1, 1-2,..., 1-M, and receives a high-frequency signal transmitted from the antenna under test. The high frequency signal received by the measurement antenna 9-a receives the high frequency signal received by the measurement antenna 9-a in the receiver 10. The average value calculation circuit 11 calculates an average value from the change in the received power of the receiver 10, and the second harmonic Fourier coefficient calculation circuit 12 expands the change in the received power of the receiver 10 by Fourier series to obtain the second harmonic component. Calculate Fourier cosine coefficient and Fourier sine coefficient. The first element electric field calculation circuit 13 calculates the element electric field from the average value calculated by the average value calculation circuit 11 and the Fourier cosine coefficient and Fourier sine coefficient of the second harmonic component calculated by the second harmonic Fourier coefficient calculation circuit 12. Find the amplitude and phase.

  Next, the operation will be described. Here, description will be made with the element antenna 1-m as a measurement target.

  The overall flow of the antenna measurement method according to Embodiment 1 will be described with reference to the flowchart shown in FIG. First, the high-frequency signal generated and transmitted by the transmitter 8 (step ST1) is input to the power distribution / combination circuit 4 and distributed according to the number of elements of the antenna under test (step ST2). The distributed high-frequency signal is given a predetermined amount of phase shift by the digital phase shifters 3-1, 3-2,. Thereafter, the high frequency signal is set to a predetermined amplitude value corresponding to the attenuation amount of the variable attenuator by the variable attenuators 2-1, 2-2,..., 2-M (step ST3), and then the element antenna. 1-1, 1-2,..., 1-M are emitted into space (step ST4). The high-frequency signal radiated into the space is combined with power in the space and received by the measurement antenna 9-a (step ST5). The array combined power received by the measurement antenna 9-a is detected by the receiver 10. These steps are performed a predetermined number of times by changing the amount of phase shift change of the digital phase shifter and the amount of attenuation of the variable attenuator corresponding to the element antenna to be measured (step ST6), and the obtained array combined power Then, a calculation process for calculating the element electric field of the element antenna to be measured is performed (step ST7). The processes that characterize the present invention will be described in detail below.

  A control method (step ST3) of the excitation amplitude and the excitation phase of the element antenna by the variable attenuation control circuit 5 and the phase control circuit 6 will be described with reference to FIG. 3 and FIG. In the step of performing steps ST1 to ST5 a predetermined number of times, the excitation amplitude and the excitation phase of the element antenna are controlled by changing the excitation amplitude and the excitation phase in association with the measurement target element antenna. For the other element antennas, measurement is performed with the excitation amplitude and the excitation phase being constant. FIG. 3 shows a change in the excitation amplitude controlled by the variable attenuation control circuit 5, and FIG. 4 shows a change in the excitation phase controlled by the phase shifter control circuit 6. In FIG. 3, the horizontal axis represents the number of times the excitation amplitude is changed, and the vertical axis represents the excitation amplitude corresponding to the number of times (herein, described as a standardized voltage value for convenience of explanation). In FIG. 3, 14-a represents a change in the excitation amplitude assumed in the first embodiment, and the excitation amplitude is changed in a cosine form from −1.0 to 1.0. The horizontal axis of FIG. 4 represents the number of times of changing the excitation phase, and corresponds to the number of times of changing the excitation amplitude shown in FIG. The vertical axis represents the excitation phase (degrees) corresponding to the number of changes. 15-a in FIG. 3 represents a change in the excitation phase assumed in the first embodiment, and is linearly changed from 0 to 360 degrees.

  The variable attenuator control circuit 5 and the phase shifter control circuit 6 control the variable attenuator 2-m and the digital phase shifter 3-m, and the excitation amplitude and the excitation phase of the element antenna 1-m are shown in FIGS. 4. Change to match the profile described in 4. For example, in the initial state (the horizontal axis is 0 in FIGS. 3 and 4), when the excitation amplitude is 1.0 and the excitation phase is 0 [degrees], it is changed 16 times (in FIGS. 3 and 4). When the horizontal axis is 16), the variable attenuator 2-m and the digital phase shifter 3-m are controlled so that the excitation amplitude is -1.0 and the excitation phase is 180 degrees. That is, here, the variable attenuator control circuit 5 and the phase shifter control circuit 6 are controlled by the amplitude phase control command circuit 7, and the excitation amplitude and the excitation phase of the element antenna to be measured are changed in synchronization. High-frequency signals including high-frequency signals whose excitation phase and excitation amplitude are changed are radiated from the corresponding element antennas.

  Next, the array combined power (step ST5) received by the measurement antenna will be described. FIG. 5 shows an array measured by the receiver 10 when the element for changing the excitation amplitude and the excitation phase is an element antenna 1-m, and the excitation amplitude and the excitation phase are changed according to the profiles shown in FIGS. An example of the change in the combined power is shown by a solid line. In FIG. 5, the horizontal axis represents the number of times the excitation amplitude and the excitation phase of the element antenna 1-m are changed, and corresponds to the horizontal axes of FIGS. The vertical axis represents the array combined power. Further, as shown in Patent Document 1 in FIG. 5, the array combined power when the excitation amplitude of the element antenna to be measured is constant and the excitation phase is linearly changed from 0 degrees to 360 degrees as shown in FIG. The change 17 in FIG.

  From FIG. 5, it can be seen that in the antenna measurement method described in Patent Document 1 described above, the change 17 in the array combined power changes in a cosine manner as described in Patent Document 1. On the other hand, it can be seen that the change 16 of the array combined power according to the first embodiment of the present invention repeats the cosine change twice with the same 32 change times, that is, doubles the cosine change. Therefore, if the maximum value, the minimum value, and the excitation phase that gives the maximum value of the double cosine change are known, the amplitude and phase of the element electric field of the element antenna 1-m can be calculated based on the same principle as in Patent Document 1. Can be sought.

  Next, a method for calculating the amplitude and phase of the element electric field (step ST7) will be described. The change 16 of the array combined power in the first embodiment of the present invention shown in FIG. 5 can be expressed by Equation 1 as a relative value from the initial state. Here, the relative value from the initial state means a relative value when the array combined power on the horizontal axis 0 in FIG.

数式１において、ｆ₀,_iはアレー合成電力、ｋ_ｍは素子アンテナ１−ｍの素子電界振幅値である。Δφはディジタル移相器の最小移相量であり、ここでは５ビットのディジタル移相器を想定しているので１１．２５度である。ｉは励振振幅および励振位相を変化させる回数であり、図３、図４、図５の横軸に相当する。また、ＹとΦ_m,₀は定数であり、それぞれ数式２と数式３で与えられる。

In Equation 1, f _{0, i} is the array combined power, k _m is the element field amplitude of the antenna elements 1-m. Δφ is the minimum phase shift amount of the digital phase shifter, and is 11.25 degrees because a 5-bit digital phase shifter is assumed here. i is the number of times the excitation amplitude and the excitation phase are changed, and corresponds to the horizontal axis of FIGS. 3, 4, and 5. Y and Φ _m , ₀ are constants and are given by Equation 2 and Equation 3, respectively.

ここで、Ｘ_ｍは素子アンテナ１−ｍの素子電界位相値である。

Here, _Xm is an element electric field phase value of the element antenna 1-m.

As can be seen from Equation 1, the change in the combined power of the array antenna according to the first embodiment changes in a cosine manner, but it becomes twice as large as i. This corresponds to a double cosine change as shown in FIG. In addition, the expressions described in Expressions 1 to 3 have the same format as the expression described in Patent Document 1. Therefore, it is possible to obtain a phase [Phi _{m, 0} similarly to Patent Document 1, an element field amplitude from the ratio r ² k _m and the element field phase X _m of the maximum value and the minimum value of the array combined power.
From Expression 1, the ratio r ² between the maximum value and the minimum value of the array combined power is given by Expression 4.

数式４より、ｒは数式５に示す２つの値をとる。

From Equation 4, r takes two values as shown in Equation 5.

数式５の右辺の符号により、素子電界振幅ｋ_ｍと素子電界位相Ｘ_ｍも２つの値をとる。数式５右辺の符号が正の場合には、素子電界振幅ｋ_ｍは数式６で与えられ、素子電界位相Ｘ_ｍは数式７で与えられる。一方、数式５右辺の符号が負の場合には、素子電界振幅ｋ_ｍは数式８で与えられ、素子電界位相Ｘ_ｍは数式９で与えられる。

The sign of the right side of Equation 5, also element field amplitude k _m and the element field phase X _m take two values. Equation 5 When the right side of the sign is positive, the element field amplitude k _m is given by Equation 6, element field phase X _m is given by Equation 7. On the other hand, when the sign is negative formula 5 right-hand side, the element field amplitude k _m is given by Equation 8, element field phase X _m is given by Equation 9.

ここで、Γは数式１０で与えられる。

Here, Γ is given by Equation 10.

As shown above, the element field amplitude k _m and the element field phase X _m, the phase [Phi _{m, 0,} is determined from the ratio r ² of the maximum value and the minimum value of the array combined power. Incidentally, in the element field amplitude k _m and the element field phase X _m, there are two sets of solutions of Equation 6 and Equation 7 or Equation 8 and Equation 9,. As described in Patent Document 1, this solution is determined by a solution that matches the design value of the element electric field amplitude, or a solution that changes the phase distribution of each element and makes the amplitude value the same. This is possible by selecting.

Next, a method for obtaining Φ _{m, 0} and r ² will be described. Φ _{m, 0} and r ² measure only the amplitude value of the array combined power by changing the array combined power measured by the receiver 10, that is, changing the excitation amplitude and excitation phase of the element antenna to be measured. it makes it possible to calculate the element field amplitude k _m and the element field phase X _m. Here, as an example, a calculation method of Φ _{m, 0} and r ² using Fourier series expansion is shown. First, the average value calculation circuit 11 obtains the average value of the change 16 in the array combined power. The average value and _{a 0.} Further, the change 16 of the array composite power is calculated from the Fourier cosine coefficient of the second harmonic and the Fourier sine coefficient of the second harmonic when the Fourier series expansion is performed by the second harmonic Fourier series expansion arithmetic circuit. The Fourier cosine coefficient of the second harmonic of the array combined power is a ₂ , and the Fourier sine coefficient of the second harmonic of the array combined power is b ₂ . a ₀ , a ₂ , and b ₂ can be obtained from Equation 11, Equation 12, and Equation 13, respectively.

ここで、ｆ_0,iは、ｉに対応したアレー合成電力の計測結果である。また、Ｎはアレー合成電力の１周期分の余弦状変化を得るために必要なアレー合成電力の計測回数であり、ここでは１６である。すなわち、特許文献１と比べて半分の測定回数で、Φ_m,0とｒ^２を算出することが可能となる。Φ_m,0は、これらの演算回路により求めた結果から数式１４で求められ、ｒ^２は数式１５で求めることができる。

Here, f _{0, i} is the measurement result of the array combined power corresponding to i. N is the number of times the array combined power is measured to obtain a cosine change for one cycle of the array combined power, and is 16 here. That is, Φ _{m, 0} and r ² can be calculated with half the number of measurements compared to Patent Document 1. Φ _{m, 0} can be obtained from Equation 14 from the results obtained by these arithmetic circuits, and r ² can be obtained from Equation 15.

Therefore, in the first embodiment of the present invention, in the first element electric field calculation circuit, from the average value a ₀ , the Fourier cosine coefficient a ₂ of the second harmonic, and the Fourier sine coefficient b ₂ of the second harmonic, 14 and Equation 15 can be used to obtain Φ _{m, 0} and r ² , respectively. Furthermore, [Phi _{m, 0} and ^{r 2,} the element field amplitude _{k m} and the element field phase _{X m} can be obtained by the equation 6-10. Here, the case where Φ _{m, 0} and r ² are calculated by Fourier series expansion of the change of the array combined power has been shown. However, for the change of the array combined power, for example, an approximate expression can be obtained using the least square method. _calculated, Φ _{m, 0} and r ² may be configured to calculate the.

In the above description, the case where the present invention is applied to the element antenna 1-m has been described. By repeating this for all elements, the element electric field amplitude and element electric field phase of all elements are obtained. Can do. For example, the invention is applied to all the elements of the phased array of 20 elements in FIGS. 6 and 7 show the results of obtaining the element field amplitude k _m and the element field phase X _m. Figure 6 shows the measurement results of the element field amplitude k _m, FIG. 7 is a measurement result of the element field phase X _m. 6 and 7, the horizontal axis represents the element number, and the vertical axis represents the amplitude or phase. In each figure, the solid line indicates the true value of the element electric field amplitude or element electric field phase, and the plot indicates the measurement result obtained by the present invention. From this, it can be seen that the measurement result obtained by the present invention is in good agreement with the true value. Further, the same measurement can be performed by changing the excitation amplitude and the excitation phase for a plurality of element antennas, and the element electric field amplitude and the element electric field phase can be obtained by regarding the plurality of element antennas as one element antenna. Can do.

  As described above, according to the first embodiment of the present invention, the element electric field amplitude and the element electric field phase of each element can be obtained by measuring the amplitude change 16 of the array combined power and calculating the result. it can. Since phase measurement is not required and the element electric field amplitude and element electric field phase can be obtained only by amplitude measurement, there is an effect that stable and highly accurate measurement is possible.

In addition, since the array combined power in Embodiment 1 of the present invention changes twice as a cosine by changing the excitation amplitude and the excitation phase in association with each other, the number of times of array combined power measurement is half. The above-mentioned Φ _{m, 0} and r ² can be calculated, and the measurement time of the element electric field can be halved as compared with Patent Document 1. Therefore, it is possible to simplify the measurement of the element electric field of the elements constituting the phased array antenna.

  Here, the case where the antenna under test is used as the transmitting antenna is shown, but when the antenna is used as the receiving antenna, that is, when the high frequency signal radiated from the measuring antenna is received by the antenna under test (phased array antenna). The same effect can be obtained. FIG. 8 shows a configuration diagram of an antenna measuring apparatus when the antenna under test is operated as a receiving antenna. In the antenna measuring apparatus shown in FIG. 8, a transmitter 8 that generates a high-frequency signal is installed on the antenna side for measurement as shown in FIG. 1, and a receiver 10, an average arithmetic circuit 11, a second harmonic Fourier coefficient arithmetic circuit on the side of the antenna under test. 12 is different in that the first element electric field calculation circuit 13 is installed.

  The operation when used as a receiving antenna will be described. In addition, let the element antenna made into a measuring object be element antenna 1-m. Similarly to the case of using as a transmission antenna, a high frequency signal generated by the transmitter 8 is radiated from the measurement antenna 9-a and received by the element antennas 1-1, 1-2,. The high-frequency signal received by the element antenna 1-m is changed in association with the excitation amplitude and the excitation phase in the same manner as in the case of operating as the transmission antenna described above, and the high-frequency signal after the change is changed by the power distribution and synthesis circuit 4. Synthesize.

  An element electric field when operated as a receiving antenna can be calculated by performing a calculation process similar to that performed when the synthesized high-frequency signal is operated as the transmitting antenna described above. Therefore, even when operated as a receiving antenna, the same effect as when operated as a transmitting antenna can be obtained.

Embodiment 2. FIG.
In the first embodiment, the excitation amplitude of each element is changed by the profile as shown in FIG. Thus, in the excitation amplitude profile shown in FIG. 3, the amplitude value may take a negative value. Since this cannot be realized by a variable attenuator, the phase value of the digital phase shifter may be offset by 180 degrees when taking a negative value. In the antenna measurement apparatus shown in Embodiment 2, when the amplitude value (voltage value) takes a negative value, the phase of the digital phase shifter is offset by 180 degrees.

  The configuration of the antenna measurement apparatus according to Embodiment 2 is the same as that shown in FIG. The operation is the same as that of the antenna measurement apparatus according to the first embodiment except for the method for controlling the excitation amplitude and the excitation phase of the element to be measured. FIG. 9 shows a change in excitation amplitude to be applied to the element to be measured, and FIG. 10 shows a change in excitation phase. In FIG. 9, the horizontal axis represents the number of times the excitation amplitude is changed, the vertical axis represents the corresponding excitation amplitude (here, described as a standardized voltage value for convenience of explanation), and 14-b represents the present embodiment. The change of the excitation amplitude assumed by the form 2 is represented. The horizontal axis in FIG. 10 represents the number of times the excitation phase is changed, the vertical axis represents the corresponding excitation phase (degrees), and 15-b represents the change in the excitation phase assumed in the second embodiment.

  As described above, in the antenna measurement apparatus according to the second embodiment, even when the excitation amplitude takes a negative value, it can be set correctly using the variable attenuator, and, as in the first embodiment, is stable and accurate. The effects of realizing high measurement, simplifying measurement, and shortening measurement time can be obtained.

Embodiment 3 FIG.
In the first embodiment, the configuration in which the excitation amplitude of the element antenna to be measured is changed in a cosine shape has been described, but in the third embodiment, the excitation amplitude of the element antenna to be measured is changed to (1 + cosine shape). A configuration to be performed will be described. Here, a case where the antenna under test (phased array antenna) is operated as a transmitting antenna will be described. FIG. 11 is a configuration diagram of an antenna measurement apparatus according to Embodiment 3 of the present invention. In FIG. 11, the same reference numerals as those in FIG. 1 shown in the first embodiment represent the same or corresponding parts. The fundamental Fourier coefficient calculation circuit 18 performs a Fourier series expansion on the change in the received power of the receiver 10 and calculates a Fourier cosine coefficient and a Fourier sine coefficient of the fundamental wave component. The second element electric field calculation circuit 19 obtains the amplitude and phase of the element electric field from the Fourier cosine coefficient and Fourier sine coefficient of the fundamental wave component calculated by the fundamental wave Fourier coefficient calculation circuit 18. That is, the average value of the array combined power and the second harmonic Fourier coefficient are calculated. In the third embodiment, the fundamental wave Fourier coefficient of the array combined power is calculated.

  Next, the operation will be described. The overall flow of the antenna measurement method according to the third embodiment is the same as that shown in the first embodiment, and is represented by the flowchart shown in FIG. The variable attenuator control circuit 5 and the phase shifter control circuit 6 control the variable attenuator 5 and the digital phase shifter 6, so that any one of the element antennas 1-1, 1-2,. The excitation amplitude and the excitation phase are changed so as to match the profiles shown in FIGS. 12 and 13, respectively. In FIG. 12, the horizontal axis represents the number of times the excitation amplitude is changed, the vertical axis represents the corresponding excitation amplitude (here, described as a normalized voltage value for convenience of explanation), and 20 is the third embodiment. Represents the change in the excitation amplitude assumed in Fig. 1. The horizontal axis in FIG. 13 represents the number of times the excitation phase is changed, the vertical axis represents the corresponding excitation phase (degrees), and 15-a represents the change in the excitation phase assumed in the first embodiment. In the third embodiment, the excitation amplitude of one arbitrary element is changed in a cosine shape with an average value of 1 and an amplitude of 1, and the excitation phase is linearly changed from 0 degrees to 360 degrees. In the first embodiment, the change in the excitation amplitude shown in FIG. 3 is changed in a cosine shape from −1.0 to 1.0, whereas in the third embodiment, the change in the cosine shape is from 0 to 2.0. To change. Further, the amplitude phase control command circuit 7 synchronizes the control of the variable attenuator control circuit 5 and the phase shifter control circuit 6 to change the excitation amplitude and the excitation phase in association with each other.

  The array combined power received by the measurement antenna will be described. The element antenna that changes the excitation amplitude and the excitation phase is the element antenna 1-m, and the array combined power measured by the receiver 10 when the excitation amplitude and the excitation phase are changed according to the profiles shown in FIGS. An example of the change is shown in FIG. In FIG. 14, the horizontal axis represents the number of times the excitation amplitude and excitation phase of the element antenna 1-m are changed, and corresponds to the horizontal axes of FIGS. 10 and 11. The vertical axis represents the array combined power. Further, reference numeral 21 in FIG. 12 represents a change in the array combined power in the third embodiment.

  In the third embodiment of the present invention, the change 21 of the array combined power measured by the receiver 10 is Fourier series expanded in the fundamental wave Fourier coefficient calculation circuit 18 to calculate the Fourier cosine coefficient and the Fourier sine coefficient of the fundamental wave component. . The second element electric field calculation circuit 19 obtains the amplitude and phase of the element electric field from the Fourier cosine coefficient and Fourier sine coefficient of the fundamental wave component calculated by the fundamental wave Fourier coefficient calculation circuit 18. Below, the detail of the calculation method of the amplitude and phase of an element electric field is demonstrated.

  The change 21 of the array combined power in the third embodiment of the present invention is expressed by Equation 16 as a relative value from the initial state. Here, the relative value from the initial state means a relative value when the array combined power on the horizontal axis 0 in FIG.

In Equation 16, _{k m} is the element field amplitude of the antenna elements 1-m, the _{X m} is the element field phase values of antenna elements 1-m. Δφ is the minimum phase shift amount of the digital phase shifter, and is 11.25 degrees because a 5-bit digital phase shifter is assumed here. i is the number of times the excitation amplitude and the excitation phase are changed, and corresponds to the horizontal axis of FIGS.

The fourth term on the right side of Equation _{16 (2k m cos (iΔφ +} X m)) is a fundamental component of the Fourier series, doubling the amplitude element field amplitude k _m, the phase is an element field phase. Thus, if the Fourier cosine coefficients and Fourier sine coefficients of the fundamental wave component obtained by the fundamental wave Fourier coefficient calculation circuit 18 and a _1, b _1, respectively, elements field amplitude k _m is obtained in Equation 17, elements field phase X _m can be obtained by Equation 18.

なお、基本波成分のフーリエ余弦係数ａ_１、フーリエ正弦係数ｂ_１は、アレー合成電力の振幅変化２１よりそれぞれ数式１９、数式２０で求めることができる。

Note that the Fourier cosine coefficient a ₁ and the Fourier sine coefficient b ₁ of the fundamental wave component can be obtained from Expression 19 and Expression 20, respectively, from the amplitude change 21 of the array combined power.

Here, f _{0, i} is a measurement result of array combined power corresponding to i, and N is the number of times of array combined power measurement. Therefore, in Embodiment 3 of the present invention, in the second element field operation circuit, from the Fourier cosine coefficients a ₁ and a fundamental wave Fourier sine coefficients b ₁ Metropolitan of the fundamental wave, element field amplitude k _m and the element field phase X _m can be obtained from Equations 17 and 18.

In the above description, the case where the present invention is applied to the element antenna 1-m has been described. By repeating this for all elements, the element electric field amplitude and element electric field phase of all elements are obtained. Can do. For example, it shows the invention is applied to all the elements of the phased array of 20 elements, the result of obtaining the element field amplitude k _m and the element field phase X _m in FIGS. Figure 15 shows the measurement results of the element field amplitude k _m, 16 is a measurement result of the element field phase X _m. The horizontal axis of each of FIGS. 15 and 16 represents the element number, and the vertical axis represents the amplitude or phase. In each figure, the solid line indicates the true value of the element electric field amplitude or element electric field phase, and the plot indicates the measurement result obtained by the present invention. From this, it can be seen that the measurement result obtained by the present invention is in good agreement with the true value. Further, the same measurement can be performed by changing the excitation amplitude and the excitation phase for a plurality of element antennas, and the element electric field amplitude and the element electric field phase can be obtained by regarding the plurality of element antennas as one element antenna. Can do.

  As described above, according to the third embodiment of the present invention, the element electric field amplitude and the element electric field phase of each element can be obtained by measuring the amplitude change 21 of the array combined power and calculating the result. it can. Since phase measurement is not required and the element electric field amplitude and element electric field phase can be obtained only by amplitude measurement, there is an effect that stable and highly accurate measurement is possible.

  In the third embodiment of the present invention, it is possible to obtain a single solution of the element electric field amplitude and the element electric field phase from the Fourier cosine series and Fourier sine series of the fundamental wave component obtained by Fourier series expansion of the change in the array composite power. It is. Therefore, in the antenna measurement device and the antenna measurement method described in Patent Document 1 and Embodiment 1, since there are two solutions, determination processing of two solutions is necessary. However, the antenna measurement according to Embodiment 3 is necessary. The apparatus and the measurement method do not require a solution determination process, and there is an effect that the measurement can be simplified.

  Although the case where the antenna under test is operated as a transmitting antenna is shown here, the case where it is operated as a receiving antenna is the same as the case where it is operated as a transmitting antenna as in the case of the first embodiment. Therefore, there is no need for a solution determination process, and the effect of simplifying the measurement can be obtained.

Embodiment 4 FIG.
In the above-described embodiment, the configuration using the variable attenuator, the variable attenuator, and the variable attenuator control circuit as the means for changing the excitation amplitude of the element antenna to be measured has been described. A configuration using a bias voltage control circuit will be described. Here, a case where the antenna under test (phased array antenna) is operated as a transmitting antenna will be described. FIG. 17 is a configuration diagram of an antenna measurement apparatus according to Embodiment 4 of the present invention. In FIG. 17, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. The amplifiers 22-1, 22-2,..., 22-M are connected to the element antennas 1-1, 1-2,..., 1-M, respectively, and the input high-frequency signal has an amplitude up to a set excitation amplitude value. To change. Amplifier. Further, the bias voltage control circuit 23 controls the gain of the amplifier by changing the bias voltage of the amplifiers 22-1, 22-2,.

  Next, the operation will be described. The operation of the fourth embodiment of the present invention is almost the same as that shown in the first embodiment, but the bias voltage control circuit 23 and the phase shifter control circuit 6 control the gain of the amplifier and the digital phase shifter. .., 1-M are different in that the excitation amplitude and the excitation phase of any one element to be measured are changed correspondingly. It is assumed that the change coincides with the profiles shown in FIGS. 3 and 4, for example. Further, the amplitude phase control command circuit 7 synchronizes the control of the bias voltage control circuit 23 and the phase shifter control circuit 6 to change the excitation amplitude and the excitation phase in association with each other.

  As described above, in the fourth embodiment, the excitation amplitude and the excitation phase of any one element can be changed as in the first embodiment, and the amplitude change 16 of the array combined power during that time is measured. By computing the result, the element electric field amplitude and element electric field phase of each element can be obtained. Accordingly, as in the first embodiment, there are effects of realizing stable and highly accurate measurement and shortening the measurement time.

  In the fourth embodiment, the excitation amplitude and the excitation phase of the element can be changed as shown in FIGS. 8 and 9, respectively. In this case, the same effect as in the second embodiment is obtained. Furthermore, in the third embodiment, the excitation amplitude and the excitation phase of the element can be changed as shown in FIGS. 12 and 13, respectively. In this case, as in the third embodiment, there is no need for a solution determination process, and the measurement can be simplified.

  Although the case where the antenna under test is operated as a transmitting antenna is shown here, the case where it is operated as a receiving antenna is the same as the case where it is operated as a transmitting antenna as in the case of the first embodiment. The effect is obtained.

Embodiment 5 FIG.
In the above-described embodiment, the case of using a measurement antenna composed of one element antenna has been described. However, in the antenna measurement apparatus according to Embodiment 5, an array antenna composed of a plurality of element antennas is used. The case where it is used as a measurement antenna will be described. Here, a case where the antenna under test (phased array antenna) is operated as a transmitting antenna will be described. FIG. 18 is a configuration diagram of an antenna measurement apparatus according to Embodiment 5 of the present invention. In FIG. 18, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. The measurement antennas 9-a, 9-b, 9-c are arranged opposite to the antennas under test, and the measurement antennas 9-a, 9-b, 9-c are arranged by the power distribution / combination circuit 24. The received signal is synthesized. Thus, in the present embodiment, an array antenna is formed by the measurement antennas 9-a, 9-b, 9-c and the power distribution / combination circuit 24. Therefore, the signal-to-noise ratio of the received signal can be improved.

  As described above, the antenna measurement apparatus according to the fifth embodiment can improve the signal-to-noise ratio of the received signal in addition to the effects shown in the first embodiment, so that the measurement accuracy is improved. effective. Although the case where the antenna under test is operated as a transmitting antenna is shown here, the same effect can be obtained when the antenna is operated as a receiving antenna as in the case of the first embodiment.

Embodiment 6 FIG.
In the above-described embodiment, the measurement antenna is arranged at a position facing the test antenna. However, in the antenna measurement apparatus according to the sixth embodiment, the measurement antenna is arranged on the same opening surface as the test antenna. To do. Here, a case where the antenna under test (phased array antenna) is operated as a transmitting antenna will be described. FIG. 19 is a configuration diagram of an antenna measurement apparatus according to Embodiment 6 of the present invention. 19, the same reference numerals as those in FIG. 18 denote the same or similar parts. In the antenna measurement apparatus shown in FIG. 19, measurement antennas 9-a to 9-d are installed on the same opening surface as element antennas 1-1 to 1-M.

  Since the antenna measurement apparatus according to the sixth embodiment has the above-described configuration, in addition to the effect shown in the fourth embodiment, an effect that the antenna measurement apparatus can be reduced in size can be obtained. Although the case where the antenna under test is operated as a transmitting antenna is shown here, the same effect can be obtained when the antenna is operated as a receiving antenna as in the case of the first embodiment.

  In each of the above embodiments, it goes without saying that the embodiments may be combined with each other without departing from the essence of the invention.

  1-1 to 1-M element antenna, 2-1 to 2-M variable attenuator, 3-1 to 3-M digital phase shifter, 4 power distribution / synthesis circuit, 5 variable attenuator control circuit, 6 phase shifter Control circuit, 7 Amplitude phase control command circuit, 8 Transmitter, 9-a to 9-c Measurement antenna, 10 Receiver, 11 Average value calculation circuit, 12 2nd harmonic Fourier coefficient calculation circuit, 13 First element electric field calculation Circuit, 14-a, 14-b Excitation amplitude change, 15-a Excitation phase change, 16 Array composite power change, 17 Array composite power change, 18 Fundamental Fourier coefficient arithmetic circuit, 19 Second element electric field Arithmetic circuit, 20 Excitation amplitude change, 21 Array composite power change, 22 Amplifier, 23 Bias voltage control circuit, 24 Power distribution synthesis circuit

Claims (14)

Among a plurality of element antennas constituting a phased array antenna, an antenna measurement method for measuring an element electric field of an element antenna to be measured,
A high frequency signal generating step for generating a high frequency signal;
Amplitude phase change step for changing the amplitude and phase of the high frequency signal corresponding to the element antenna to be measured among the high frequency signals generated in the high frequency signal generation step,
High-frequency signal radiation generated from the plurality of element antennas corresponding to the high-frequency signals generated in the high-frequency signal generation step and including the high-frequency signals whose amplitude and phase are changed in the amplitude phase change step Steps,
A high-frequency signal receiving step of receiving a high-frequency signal radiated from the plurality of element antennas in the high-frequency signal radiating step with a measurement antenna;
An element electric field calculating step for calculating an element electric field of the element antenna to be measured based on the high frequency signal received in the high frequency signal receiving step;
An antenna measurement method comprising: Among a plurality of element antennas constituting a phased array antenna, an antenna measurement method for measuring an element electric field of an element antenna to be measured,
A high frequency signal generating step for generating a high frequency signal;
A high-frequency signal emission step of radiating the high-frequency signal generated in the high-frequency signal generation step from a measurement antenna;
A high-frequency signal receiving step of receiving the high-frequency signals radiated in the high-frequency signal radiating step by the plurality of element antennas, respectively;
Of the high-frequency signal received in the reception step, an amplitude phase change step for changing the amplitude and phase of the high-frequency signal received by the element antenna to be measured in association with each other;
A high-frequency signal synthesis step of synthesizing a high-frequency signal received by the plurality of element antennas corresponding to the high-frequency signal reception step, the high-frequency signal including a high-frequency signal whose amplitude and phase are changed in the amplitude phase control step; ,
An element electric field calculation step for calculating an element electric field of the element antenna to be measured based on the high frequency signal synthesized in the high frequency signal synthesis step;
An antenna measurement method comprising:   3. The antenna measurement according to claim 1, wherein in the amplitude phase changing step, the amplitude of a high-frequency signal corresponding to the element antenna to be measured is changed using a variable attenuator or an amplifier. Method. In the amplitude phase changing step, the amplitude of the high-frequency signal corresponding to the element antenna to be measured is changed to a cosine shape, and the phase of the high-frequency signal corresponding to the element antenna to be measured is linearly changed from 0 degrees to 360 degrees. Let
In the element electric field calculation step, calculating an average value of the element electric field and a Fourier coefficient of the second harmonic,
The antenna measurement method according to any one of claims 1 to 3, wherein: In the amplitude phase changing step, the amplitude of the high-frequency signal corresponding to the element antenna to be measured is (1 + cosine), and the phase of the high-frequency signal corresponding to the element antenna to be measured is from 0 degrees to 360 degrees. Change linearly,
In the element electric field calculation step, calculating an average value of the element electric field and a Fourier coefficient of the fundamental wave,
The antenna measurement method according to any one of claims 1 to 3, wherein:   The antenna measurement method according to claim 1, wherein the measurement antenna is an array antenna including a plurality of element antennas and a power distribution / combination circuit.   The antenna measurement method according to claim 1, wherein the measurement antenna is installed on the same opening surface as the plurality of element antennas. Among a plurality of element antennas constituting a phased array antenna, an antenna measurement device that measures an element electric field of an element antenna to be measured,
High-frequency signal generating means for generating a high-frequency signal;
Amplitude phase changing means for changing the amplitude and phase of the high frequency signal radiated from the element antenna to be measured among the high frequency signals generated by the high frequency signal generating means and radiated from the plurality of element antennas. When,
A measurement antenna for receiving high-frequency signals radiated from the plurality of element antennas;
An element electric field calculation means for calculating an element electric field of the element antenna to be measured based on a high-frequency signal received by the measurement antenna;
An antenna measuring device comprising: Among a plurality of element antennas constituting a phased array antenna, an antenna measurement device that measures an element electric field of an element antenna to be measured,
High-frequency signal generating means for generating a high-frequency signal;
A measurement antenna that radiates a high-frequency signal generated by the high-frequency signal generating means;
Amplitude phase changing means for changing the amplitude and phase of a high frequency signal radiated from the measurement antenna and received by the plurality of element antennas and received by the element antenna to be measured in association with each other. ,
High-frequency signal synthesis means for synthesizing a high-frequency signal received by the plurality of element antennas, the high-frequency signal including a high-frequency signal whose amplitude and phase are changed by the amplitude phase change means;
An element electric field calculation means for calculating an element electric field of the element antenna to be measured based on the high frequency signal synthesized by the high frequency signal synthesis means;
An antenna measuring device comprising:   10. The antenna measurement according to claim 8, wherein the amplitude phase changing unit includes a variable attenuator or an amplifier that changes an amplitude of a high-frequency signal corresponding to the element antenna to be measured. apparatus. The amplitude phase change means linearly changes the amplitude of the high frequency signal corresponding to the element antenna to be measured in a cosine shape and the phase of the high frequency signal corresponding to the element antenna to be measured from 0 degrees to 360 degrees. Let
An element electric field calculation means calculates an average value of the element electric field and a Fourier coefficient of a second harmonic,
The antenna measurement device according to claim 8, wherein The amplitude phase changing means sets the amplitude of the high frequency signal corresponding to the element antenna to be measured to (1 + cosine) and the phase of the high frequency signal corresponding to the element antenna to be measured from 0 degree to 360 degrees. Change linearly,
The element electric field calculation means calculates an average value of the element electric field and a Fourier coefficient of the fundamental wave,
The antenna measurement device according to claim 8, wherein   The antenna measurement apparatus according to claim 8, wherein the measurement antenna is an array antenna including a plurality of element antennas and a power distribution / combination circuit.   The antenna measurement device according to claim 8, wherein the measurement antenna is installed on the same opening surface as the plurality of element antennas.

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