JP2013130405A - Antenna impedance measuring method, active phased array antenna and antenna system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the antenna impedance of an element antenna in an active state of an active phased array antenna while maintaining performance uniformity of element antennae.SOLUTION: While singly operating a feeder circuit 22, a detector 6 provided in the feeder circuit 22 of one of active phased array antennae 20 is used to detect an electrical physical quantity for calculating a reflection coefficient of a load by supplying power from the feeder circuit 22 to the load for each case where each of a plurality of loads having different known impedance values is connected to a feeder 26 to an element antenna 1. A storage section 8 stores calibration data in which the impedance value of the load is made corresponding to the detected electrical physical quantity. While operating the active phased array antenna 20 including the feeder circuit 22, the electrical physical quantity of the feeder circuit 22 is then measured, and an impedance value corresponding to the measured electrical physical quantity is calculated from calibration data.

Description

  The present invention relates to a method for measuring the dynamic antenna impedance of each element antenna in an active phased array antenna.

  In order to know the exact characteristics of the active phased array antenna, it is necessary to measure the impedance (antenna impedance) of the element antenna in the operating state of the active phased array antenna. Patent Document 1 and Patent Document 2 describe techniques for measuring the active impedance of an array antenna. In the active impedance measuring apparatus of Patent Document 1, the active impedance is measured by extracting the reflected wave with a directional coupler provided at the output end of the element antenna and detecting the power.

  In the antenna impedance measurement method of Patent Document 2, an antenna element is connected with reference to an output to an isolation terminal in a state where an output terminal of a hybrid circuit that feeds an arbitrary antenna element of a circular knitted wave array antenna is opened or short-circuited. The active impedance in the operating state of the array antenna is measured by measuring the output to the same terminal in the state.

Japanese Utility Model Publication No. 2-107079 JP-A-5-157782

  In the active impedance measuring apparatus of Patent Document 1, a method of extracting a reflected wave by using a directional coupler and detecting the power is applied. However, in this method, a directional coupler is added to a specific element antenna in the element antenna that should be uniform. Alternatively, a performance difference occurs between a measurement element antenna having a coupler and an element antenna in actual operation. For this reason, there is a possibility that the characteristic difference of the element antenna may affect the evaluation result, leading to a problem that leads to a decrease in measurement accuracy.

  In the antenna impedance measurement method of Patent Document 2, it is necessary to measure the output of the isolation terminal of the hybrid circuit of the antenna element of interest in the array antenna state in the excitation state of the antenna element, the open state of the hybrid output, and the short circuit state. There is a problem that the measurement procedure in the state of the array antenna is complicated.

  The present invention has been made to solve the above-described problems, and maintains the performance uniformity of the element antenna of the active phased array antenna to be evaluated, and the antenna impedance of the element antenna in the operating state of the active phased array antenna is reduced. The purpose is to measure easily.

  An antenna impedance measurement method according to a first aspect of the present invention detects an electrical physical quantity for calculating a reflection coefficient of a load connected to a feed line, which is provided in a feed circuit of one element antenna of an active phased array antenna. A plurality of loads having different known impedance values are respectively connected to the power supply line to the element antenna in a state where the power supply circuit of the single element antenna having the detection unit is operated independently using the detection unit. In each case, power is supplied from the power supply circuit to the load to detect the electrical physical quantity. Calibration data in which the impedance value of the load connected to the power supply line is associated with the detected electrical physical quantity is stored. The characteristics of the power supply circuit including the element antenna having the detection unit and the power supply circuit viewed from the output terminal of the power supply circuit of the element antenna having the detection unit are Measure the electrical physical quantity of the power supply circuit of the element antenna with the detection unit while operating the active phased array antenna that is equivalent to the observed characteristics, and calculate the impedance value corresponding to the measured electrical physical quantity from the calibration data .

  According to the present invention, it is possible to measure the antenna impedance of the element antenna in the operating state of the active phased array antenna while maintaining the uniformity of the element antenna.

It is a block diagram which shows the structural example of the antenna system which concerns on Embodiment 1 of this invention. 4 is a block diagram showing a configuration for measuring calibration data according to Embodiment 1. FIG. 5 is a flowchart showing an example of calibration data acquisition operation according to the first embodiment. 3 is a flowchart showing an example of an antenna impedance measurement operation according to the first embodiment. It is a block diagram which shows the structural example of the antenna system which concerns on Embodiment 2 of this invention. 6 is a block diagram illustrating a configuration for measuring calibration data according to Embodiment 2. FIG. FIG. 10 is a conceptual diagram of a relationship between a power propagation direction and current consumption in the second embodiment. FIG. 10 is a conceptual diagram of a relationship between a change in antenna impedance due to a change in power propagation direction and a power added efficiency in the final stage amplifier in the second embodiment. 10 is a flowchart illustrating an example of calibration data acquisition operation according to the second embodiment. 6 is a flowchart illustrating an example of an antenna impedance measurement operation according to the second embodiment. It is a block diagram which shows the structural example of the active phased array antenna which concerns on Embodiment 3 of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each figure, the same or equivalent members and parts are described with the same reference numerals.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration example of an antenna system according to Embodiment 1 of the present invention. The antenna system includes an active phased array antenna 20, a load pull data storage unit 10, a storage unit 8, a calculation unit 18, and a display unit 11.

  The active phased array antenna 20 includes a plurality of element antennas 1 and a power feeding circuit 21 that feeds power to each element antenna 1. Each power supply circuit 21 includes a phase shifter 3, a final stage amplifier 2, a circulator 4, and a dummy unit 41. The dummy unit 41 terminates the received signal (reflected power) reflected by the element antenna 1 and separated by the circulator 4 without reflection. The received signal includes a signal reflected by the element antenna 1 (load) and a signal input to the element antenna 1 by an external electric field. However, if the influence of the external electric field can be ignored, the received signal is only a reflected signal.

  The feed circuit 22 connected to one element antenna 1 of the active phased array antenna 20 includes a coupler 5 and a detector 6 in addition to the configuration of the feed circuit 21. The coupler 5 generates high frequency power that is proportional to the reflected power flowing through the dummy portion 41. The detector 6 detects high frequency power proportional to the reflected power generated by the coupler 5. The detector 6 can detect the magnitude of the reflected power of the element antenna 1 and the phase with respect to the output.

  In FIG. 1, a circuit that generates a transmission signal of the active phased array antenna 20 and inputs the transmission signal to the input terminals 25 of the power feeding circuits 21 and 22 is omitted. In the active phased array antenna 20, the phase of each element antenna 1 is set in the phase shifter 3. The load pull data storage unit 10 in FIG. 1 stores the phase to be set for each element antenna, and sets each phase in the phase shifter 3 of the power feeding circuits 21 and 22 of each element antenna 1. The transmission signal input from the input terminal 25 is phase-shifted to the phase set by the phase shifter 3 and amplified by the final stage amplifier 2. A current is supplied to the final stage amplifier 2 by a power supply 30. Each element antenna 1 radiates radio waves with a set phase. As a result, the radiated radio waves have directivity in a direction (arrow 13 in FIG. 1) in which the radiated radio waves of the element antennas are intensified according to the set phase.

  In the active phased array antenna 20, each element antenna 1 has a self-radiation impedance and a mutual radiation impedance generated by receiving a radiation electric field (arrow 12 in FIG. 1) of the other element antennas 1. The antenna impedance of each element antenna 1 is the sum of self-radiation impedance and mutual radiation impedance. The mutual radiation impedance can change according to the frequency of the radio wave and the phase difference between the element antennas.

  The antenna system according to the first embodiment further includes a storage unit 8, a calculation unit 18, and a display unit 11. The storage unit 8, the calculation unit 18, and the display unit 11 can be realized by a computer. In the first embodiment, a plurality of loads having different known impedance values are respectively connected to the feeder line 26 to the element antenna 1 of the feeder circuit 22 in a state where the feeder circuit 22 having the detector 6 is operated alone. In each case, power is supplied from the power supply circuit 22 to the load, and the magnitude of the reflected power detected by the detector 6 and the phase with respect to the output are measured. The storage unit 8 stores calibration data that associates the magnitude and phase of the reflected power measured in advance with the impedance value of the load connected to the feeder line 26. The reflection coefficient (complex number) by the load is represented by the ratio of the reflected power (complex number) to the output power (complex number).

  Next, in a state where the active phased array antenna 20 including the feeding circuit 22 of the element antenna 1 having the detector 6 is operated, the magnitude of the reflected power and the phase with respect to the output are measured by the detector 6. The magnitude and phase of the measured reflected power are stored in the storage unit 8 in association with the phase set in the phase shifter 3 at that time. The calculation unit 18 calculates an impedance value corresponding to the magnitude and phase of the reflected power measured with the active phased array antenna 20 activated from the calibration data. The calculation unit 18 displays the calculated impedance value and the phase set in the phase shifter 3 at that time on the display unit 11.

  FIG. 2 is a block diagram showing a configuration for measuring calibration data according to the first embodiment. The feeding circuit 22 is taken out from the active phased array antenna 20 shown in FIG. 1 and operated independently. Also in FIG. 2, a circuit for supplying an input signal is omitted. The load pull tuner 9 is connected to a point (feed line 26) where the element antenna 1 of the feed circuit 22 is connected. The load pull tuner 9 is a load capable of selecting and setting various impedance values. The load pull tuner 9 needs to be configured so that noise due to external radio waves or the like is not input to the power feeding circuit 22 side.

  With the load pull tuner 9 changing the impedance value of the load connected to the power supply circuit 22 and operating the power supply circuit independently for each load impedance value, the detector 6 determines the magnitude of the reflected power and the transmission signal. Measure the phase with respect to. Calibration data that associates the magnitude and phase of the measured reflected power with the impedance value of the load at that time is stored in the storage unit 8. At this time, the impedance value of the load and the magnitude and phase of the reflected power may be displayed on the display unit 11.

  The impedance value set by the load pull tuner 9 is selected so as to include a range of impedance values that the element antenna 1 can assume in a state where the active phased array antenna 20 is operated. Moreover, it is preferable to set the impedance value as fine as possible within the range and measure the reflected power.

  Returning to the configuration of the active phased array in FIG. 1, the reflected power of the feeding circuit 22 is measured in a state where the entire active phased array antenna 20 including the feeding circuit 22 of the element antenna 1 having the detector 6 is operated. In this case, the active phased array antenna 20 is placed in an anechoic chamber for measurement so that reflection or radiation from the outside of the active phased array antenna 20 is not input to the element antenna 1. At the time of measurement, the phase amount from each element antenna 1 is changed, and the reflected power is acquired as data for each set phase amount.

  The calculation unit 18 calculates the load impedance value corresponding to the measured magnitude and phase of the reflected power from the calibration data. If the magnitude and phase of the measured reflected power are in the calibration data, the corresponding impedance value of the load can be regarded as the antenna impedance value of the element antenna 1 at that time. When the magnitude and phase of the measured reflected power are not included in the calibration data, the impedance value is calculated by appropriately interpolating. If the calibration data is measured sufficiently finely, the antenna impedance of the element antenna 1 in which the active phased array antenna 20 is in an operating state can be measured with the required accuracy. As described above, the calculation unit 18 displays the calculated impedance value and the phase set in the phase shifter 3 at that time on the display unit 11.

  FIG. 3 is a flowchart showing an example of calibration data acquisition operation according to the first embodiment. In the configuration shown in FIG. 2, the load impedance value of the load pull tuner 9 is set (step S11). And it outputs from the electric power feeding circuit 22 (step S12). While the power is being output from the power feeding circuit 22, the magnitude and phase of the reflected power are measured by the detector 6 of the power feeding circuit 22 (step S13). Once measured, the output from the power feeding circuit 22 may be stopped. The magnitude and phase of the measured reflected power are stored in the storage unit 8 in association with the impedance value of the load (step S14). If there is a load impedance value to be set in the load pull tuner 9 (step S15; YES), the process returns to step S11 to repeat the load impedance setting. If there is no load impedance value to be set (step S15; NO), the calibration data acquisition ends. Subsequently, the antenna impedance is measured.

  FIG. 4 is a flowchart showing an example of the antenna impedance measurement operation according to the first embodiment. With the configuration of the antenna system shown in FIG. 1, the phase of each element antenna is set in the phase shifter 3 of each of the feeder circuits 21 and 22 (step S21). And it outputs from the active phased array antenna 20 (step S22). In this state, the magnitude and phase of the reflected power are measured by the detector 6 of the feeder circuit 22 (step S23). The magnitude and phase of the measured reflected power and the set phase are stored in the storage unit 8 (step S24). The calculation unit 18 calculates an impedance corresponding to the magnitude and phase of the reflected power (step S25).

  If there is a phase to be set for the element antenna whose antenna impedance is to be measured (step S26; YES), the process returns to step S21 to repeat the phase setting for each element antenna. If there is no phase to be set for the element antenna (step S26; NO), the calculation unit 18 displays the measured antenna impedance and the phase of the element antenna at that time on the display unit 11 (step S27).

  As described above, according to the first embodiment, the antenna impedance of the element antenna 1 can be measured while the active phased array antenna 20 is operated. In the antenna impedance measurement, the characteristics of the element antenna 1 are kept uniform.

  In the first embodiment, the power supply circuits 21 and 22 of the element antenna 1 constituting the active phased array antenna 20 have the same electrical performance and form regardless of the presence or absence of the detector, and the influence due to the difference between them can be eliminated. it can. In general, the influence of the circulator 4 on the S-parameter (input / output load, its passage and isolation) depending on whether the detector 6 is installed in the dummy part of the circulator 4 via the coupler 5 can be ignored. Therefore, since the circulator 4 can be seen in the impedance when the feeder circuits 21 and 22 are viewed from the element antenna 1 side, there is no difference between the feeder circuit 22 including the detector 6 and the other feeder circuits 21. Further, the detector 6 itself can be added without affecting the electrical length and output power from the inside of the feeding circuit to the feeding point of the element antenna 1, so that there is no difference in performance of the element antenna 1. As a result, measurement errors caused by the presence or absence of detection can be suppressed, which contributes to improvement in antenna impedance measurement accuracy.

(Embodiment 2)
FIG. 5 is a block diagram showing a configuration example of the antenna system according to Embodiment 2 of the present invention. The power feeding circuit 23 according to the second embodiment includes a band pass filter 17 instead of the circulator 4. In addition, the power supply circuit 24 that measures the electrical physical quantity for calculating the reflection coefficient includes an ammeter 7 that measures the current consumed by the final stage amplifier 2 instead of the detector 6. Other configurations are the same as those in the first embodiment.

  In the second embodiment, a plurality of loads having different known impedance values are connected to the power supply line 26 to the element antenna 1 of the power supply circuit 24 in a state where the power supply circuit 24 including the ammeter 7 is operated alone. In each case, power is supplied from the power supply circuit 24 to the load, and the current consumed by the final stage amplifier 2 is measured by the ammeter 7. Further, the output power at that time (the power input to the load side excluding the reflected power) is simultaneously measured. The storage unit 8 stores calibration data in which the consumption current and output power measured in advance are associated with the impedance value of the load connected to the feeder line 26. The reflection coefficient (complex number) by the load can be calculated from the output power and the power consumption. The power consumption can be calculated from the current consumption and the input voltage. The calibration data may store power consumption instead of current consumption.

  FIG. 6 is a block diagram showing a configuration for measuring calibration data according to the second embodiment. Also in the second embodiment, the magnitude of the current consumed by the final stage amplifier 2 in a state where the impedance value of the load connected to the power feeding circuit 24 is changed and the power feeding circuit is operated independently for each impedance value of the load. Is measured with an ammeter 7. At the same time, the output power of the power feeding circuit 24 is measured by the load pull tuner 9. As the load pull tuner 9, one that can measure the power input to the load pull tuner 9 (output power of the power feeding circuit 24) is used.

  Next, the current consumed by the final stage amplifier 2 is measured by the ammeter 7 in a state where the active phased array antenna 20 including the feeding circuit 24 of the element antenna 1 having the ammeter 7 is operated. Further, the radiated power of the entire active phased array antenna 20 is measured. The measurement of the radiated power can be performed using, for example, an all-spherical scanning method or a modulated probe array method. From the measured radiated power, the output power of the element antenna 1 connected to the feeder circuit 24 is calculated. The output power of the element antenna 1 can be calculated in advance by measuring the contribution rate of the element antenna 1 to the radiated power for each phase amount set in the element antenna 1 and multiplying the radiated power by the contribution rate. When the phase amount (phase difference) set in the element antenna 1 is small, the difference in contribution rate for each element antenna 1 can be ignored. Therefore, the output per element antenna 1 is obtained by dividing the radiated power by the number of element antennas 1. It can be regarded as electric power.

  The storage unit 8 stores the measured magnitude of current consumption and output power in association with the phase set in the phase shifter 3 at that time. FIG. 7 is a conceptual diagram of the relationship between the power propagation direction (phase) and current consumption in the second embodiment.

  The calculation unit 18 calculates an impedance value corresponding to the magnitude of the current consumption and the output power measured in a state where the active phased array antenna 20 is operated from the calibration data. When calculating the output power of the element antenna 1 from the radiated power of the active phased array antenna 20, since the phase of the output power cannot be known, the impedance value is calculated as follows.

  FIG. 8 is a conceptual diagram of the relationship between the change in antenna impedance due to the change in the power propagation direction and the power added efficiency in the final stage amplifier in the second embodiment. FIG. 8 shows power consumption and output power corresponding to the impedance value of the load. In FIG. 8, the correspondence between the power consumption and the load impedance value is represented by a solid equal power consumption line (contour) 15. For example, the load impedance corresponding to the power consumption at a certain point on the contour 15 is the resistance and reactance at that point read by the Smith chart 14 of FIG. Further, the correspondence between the output power and the impedance value of the load is represented by a dotted equal output power line (contour) 16. A set of power consumption and output power is represented by an intersection of a contour 15 corresponding to power consumption and a contour 16 corresponding to output power. The resistance and reactance at the intersection read on the Smith chart 14 is the load impedance value (antenna impedance) for the set of power consumption and output power.

  The intersection of the contour 15 and the contour 16 (for example, a black circle in FIG. 8) is generally two points, but can be determined as one of them from other conditions. For example, the variation in antenna impedance can be estimated from the current consumption for the setting of the power propagation direction in FIG. Of the impedances at the two intersections, the one closer to the estimated fluctuation of the antenna impedance can be used as the antenna impedance.

  In the above, the method for calculating the antenna impedance from the power consumption and the output power has been described using the Smith chart 14 in order to facilitate understanding conceptually. The calculation unit 18 generates an equal power consumption (current) line (contour) 15 and an equal output power line (contour) 16 from the calibration data using a data string or an equation of an approximate curve. In addition, the estimated variation range of the antenna impedance is stored. Then, the intersection of the measured power consumption (current) contour 15 and the output power contour 16 is calculated, and the impedance closer to the estimated antenna impedance fluctuation range among the impedances corresponding to the intersection is calculated as the power consumption (current). And the antenna impedance corresponding to the output power.

  FIG. 9 is a flowchart illustrating an example of calibration data acquisition operation according to the second embodiment. In the configuration shown in FIG. 6, the load impedance value of the load pull tuner 9 is set (step S31). And it outputs from the electric power feeding circuit 24 (step S32). In the state of outputting from the power feeding circuit 3, the current consumption is measured by the ammeter 7 of the power feeding circuit 24, and the output power is measured by the load pull tuner 9 (step S33). Once measured, the output from the power feeding circuit 24 may be stopped. The measured current consumption and output power are stored in the storage unit 8 in association with the load impedance value (step S34). If there is a load impedance value to be set in the load pull tuner 9 (step S35; YES), the process returns to step S31 to repeat the load impedance setting. If there is no load impedance value to be set (step S35; NO), calibration data acquisition is terminated. Subsequently, the antenna impedance is measured.

  FIG. 10 is a flowchart illustrating an example of the antenna impedance measurement operation according to the second embodiment. With the configuration of the antenna system shown in FIG. 5, the phase of each element antenna is set in the phase shifter 3 of each of the feeder circuits 23 and 23 (step S41). And it outputs from the active phased array antenna 20 (step S42). In this state, the consumption current is measured by the ammeter 7 of the power feeding circuit 24, and the radiated power of the active phased array antenna 20 is measured (step S43). The calculation unit 18 calculates the output power of the element antenna 1 connected to the power feeding circuit 24 from the measured radiated power (step S44). The measured current consumption and output power and the set phase are stored in the storage unit 8 (step S45).

  The calculation unit 18 calculates the impedance corresponding to the current consumption and the output power (step S46). For example, as described above, the intersection of the equal power consumption line 15 corresponding to the current consumption and the equal output power line 16 corresponding to the output power is calculated, and is close to the estimated antenna impedance fluctuation range among the impedance corresponding to the intersection. Is the antenna impedance corresponding to the power consumption (current) and the output power.

  If there is a phase to be set for the element antenna whose antenna impedance is to be measured (step S47; YES), the process returns to step S41 to repeat the phase setting for each element antenna. If there is no phase to be set for the element antenna (step S47; NO), the calculation unit 18 displays the measured antenna impedance and the phase of the element antenna at that time on the display unit 11 (step S48).

  As described above, according to the second embodiment, the antenna impedance of the element antenna 1 can be measured while the active phased array antenna 20 is operated. In the antenna impedance measurement, the characteristics of the element antenna 1 are kept uniform.

  In the second embodiment, the element antennas constituting the active phased array antenna 20 have the same electrical performance and form regardless of the presence or absence of the current monitoring function (ammeter 7), and the influence of these differences can be eliminated. . In general, the influence on the S-parameter (input / output load, its passage, isolation) of the amplifier due to the presence or absence of the current monitoring function of the amplifier is negligible. Therefore, since the amplifier 2 can be seen in the impedance when the feeder circuits 21 and 22 are viewed from the element antenna 1 side, there is no difference between the element antenna having the current monitoring function and the other element antennas. In addition, the current monitoring function itself can be added without affecting the electrical length from the power feeding circuit to the power feeding point of the element antenna 1 and the output power, so that there is no difference in the performance of the element antenna. As a result, measurement errors caused by the presence or absence of the current monitoring function can be suppressed, which contributes to improvement in antenna impedance measurement accuracy.

(Embodiment 3)
FIG. 11 is a block diagram showing a configuration example of the active phased array antenna 20 according to Embodiment 3 of the present invention. In the third embodiment, the power supply circuit 21 including the circulator 4 assumed in the first embodiment and the power supply circuit 24 having the amperemeter 7 without the circulator 4 assumed in the second embodiment are combined. . In the third embodiment, antenna impedance measurement is performed in the same procedure as in the second embodiment.

  One purpose of measuring the antenna impedance in the operating state of the active phased array antenna 20 is to investigate the effect of variations in antenna impedance on the performance of the final stage amplifier 2. In the active impedance measuring apparatus of Patent Document 1, the performance of the final stage amplifier 2 is indirectly evaluated, and thus there is a problem that leads to a decrease in measurement accuracy.

  In the third embodiment, when investigating the influence of active impedance on the final stage amplifier 2, it is an object to directly measure the performance fluctuation of the final stage amplifier 2 and increase the measurement accuracy.

  According to the third embodiment, it is possible to examine whether or not the circulator 4 can be omitted for improving the performance of the power feeding circuit 21 including the circulator 4 for stabilizing the performance. The purpose of the configuration of the third embodiment is to eliminate the loss of the circulator 4 after determining the influence on the active impedance due to the omission of the circulator 4. In this case, it is necessary to estimate the influence of the active impedance on the current consumption of the final stage amplifier 2.

  According to the configuration of the third embodiment, it is not necessary to estimate the influence on the active impedance due to the output direction (phase amount) of the radio wave of the active phased array antenna 20, and the influence on the current consumption can be estimated directly. The measurement procedure is the same as the measurement procedure shown in the second embodiment. According to the active phased array antenna 20 according to the third embodiment, whether or not the circulator 4 is necessary can be estimated by replacing one power feeding circuit 21.

1 element antenna
2 Final stage amplifier
3 Phase shifter
4 Circulator
5 coupler
6 Detector
7 Ammeter
8 storage unit
9 Road pull tuner
10 Load pull data storage
11 Display
14 Smith Chart
15 Consumption power line (contour)
16 Equal output power line (contour)
17 Bandpass filter
18 Calculation unit
20 Active phased array antenna 21, 22, 23, 24 Feed circuit
25 Input terminal
26 Feeding line
30 power supply
41 Dummy

Claims (6)

One element having the detection unit using a detection unit for detecting an electrical physical quantity for calculating a reflection coefficient of a load connected to a power supply line, which is provided in a power supply circuit of one element antenna of an active phased array antenna Power is supplied from the power supply circuit to the load every time a plurality of loads having different known impedance values are connected to the power supply line to the element antenna while the power supply circuit of the antenna is operated independently. A detecting step for detecting the electrical physical quantity;
A storage step of storing calibration data in which the impedance value of the load connected to the feeder line is associated with the detected electrical physical quantity;
The characteristic of the power supply circuit including the element antenna having the detection unit and the power supply circuit viewed from the output terminal of the power supply circuit of the element antenna having the detection unit is from the output terminal of the power supply circuit of the element antenna not including the detection unit. A measurement step of measuring the electrical physical quantity of the power feeding circuit of the element antenna having the detection unit in a state in which the active phased array antenna that is equivalent to the characteristics seen is operated;
A calculation step of calculating an impedance value corresponding to the electrical physical quantity measured in the measurement step from the calibration data;
An antenna impedance measuring method comprising: In the detection step, the power proportional to the reflected signal is detected by using a detector that detects power proportional to the reflected signal flowing in the dummy part that is separated by the circulator inserted in the feeder line of the element antenna and terminates without reflection. And the phase with respect to the transmitted signal,
In the storing step, the magnitude of power proportional to the reflected signal and the phase with respect to the transmission signal are stored in association with the impedance value of the load connected to the feeder line.
The antenna impedance measuring method according to claim 1. In the detection step, an ammeter that detects a current consumed by a final stage amplifier of the power supply circuit of the element antenna and a wattmeter that detects output power from the power supply line are used, and a final stage of the power supply circuit. Detect the amount of current consumed by the amplifier and the output power from the feeder line,
In the storing step, the magnitude of the current consumed by the final stage amplifier of the power supply circuit and the output power from the power supply line are stored in association with the impedance value of the load connected to the power supply line,
In the measurement step, the radiated power of the active phased array antenna is measured, converted into the output power of the element antenna having the detection unit, and consumed by the final stage amplifier of the power feeding circuit of the element antenna having the detection unit. Measure the magnitude of the current
The antenna impedance measuring method according to claim 1. The power supply circuit of each element antenna of the active phased array antenna includes a circulator inserted into the power supply line, and a dummy section that terminates the reflection signal separated by the circulator without reflection,
An active phased array antenna comprising a detector for detecting power proportional to the reflected signal flowing in the dummy section in a power feeding circuit of one element antenna of the active phased array antenna. The power supply circuit of each element antenna of the active phased array antenna is equipped with a band pass filter inserted in the power supply line,
An active phased array antenna, wherein a power supply circuit for one element antenna of the active phased array antenna includes an ammeter for detecting a current consumed by a final stage amplifier of the power supply circuit. A feed circuit of one element antenna of an active phased array antenna has a detection unit for detecting an electrical physical quantity for calculating a reflection coefficient of a load connected to a feed line, and feeds the element antenna having the detection unit The active phased array antenna whose characteristics when viewed from the output end of the circuit are equivalent to the characteristics when viewed from the output end of the power feeding circuit of the element antenna that does not have the detection unit,
A plurality of loads having different known impedance values on the power supply line to the element antenna of the power supply circuit in a state where the power supply circuit of one element antenna having the detection unit of the active phased array antenna is operated alone Calibration data in which electric power is supplied from the power supply circuit to the load and detected by the detection unit and the impedance value of the load connected to the power supply line is stored. A storage unit
A calculation unit that calculates an impedance value corresponding to the electrical physical quantity detected by the detection unit from the calibration data in a state in which the active phased array antenna including the element antenna including the detection unit is operated;
An antenna system comprising:

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