JP5168940B2 - Antenna measuring device - Google Patents

Description

  The present invention relates to an antenna measurement apparatus for measuring radiation characteristics or reception sensitivity characteristics (antenna pattern characteristics) of an antenna to be measured.

  Various proposals have been made regarding an antenna measurement apparatus that automatically performs antenna pattern measurement. A conventional antenna measuring apparatus has an antenna to be measured mounted on a turntable and an opposed antenna facing the antenna to be measured. The antenna pattern can be measured by reading the reception data of the opposing antenna at every predetermined rotation angle of the turntable (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 7-229942

  In a conventional antenna measurement device, when the antenna to be measured is, for example, a phased array antenna, the phaser control circuit inside the antenna control device performs phaser control in the antenna to be measured to form an arbitrary one beam. Rotate the turntable to measure the antenna pattern. According to the conventional method, since the rotating table is rotated by the number of antenna patterns that need to be acquired and the antenna pattern is measured, it takes time to measure for the time for which the rotating table rotates. Therefore, when the number of antenna patterns to be acquired increases as in the case of a phased array antenna, there is a problem that it takes a lot of time to measure the antenna pattern as a result.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain an antenna measurement apparatus that can shorten the time for measuring an antenna pattern as compared with the conventional one.

An antenna measuring apparatus according to the present invention comprises a turntable for rotating a measured antenna whose beam pattern can be varied,
A turntable controller for driving the turntable and measuring a rotation angle of the antenna under measurement;
Opposing antenna that faces the antenna to be measured and transmits or receives radio waves to and from the antenna to be measured;
A signal processor that sequentially changes the beam pattern of the antenna under measurement when the rotation angle measured by the turntable control unit reaches a predetermined measurement angle;
Measuring a power ratio of radio waves propagated between the antenna to be measured and the counter antenna, and a test transceiver for sequentially storing the measurement data of the power ratio for each beam pattern;
The measurement angle of the antenna to be measured is sequentially changed, the measurement data of the power ratio stored by the test transceiver is sequentially acquired for each measurement angle, and based on the measurement data acquired at all measurement angles. A computer that measures the antenna pattern characteristics of the antenna under measurement corresponding to each of a number of beam patterns;
It is equipped with.

In addition, a turntable for rotating the antenna under measurement;
A turntable controller for driving the turntable and measuring a rotation angle of the antenna under measurement;
A receiving antenna for receiving a transmission radio wave radiated from the antenna under measurement;
When the rotation angle measured by the turntable control unit reaches a predetermined measurement angle, the frequency of the antenna under measurement is sequentially changed, the transmission signal is fed to the antenna under measurement, and the reception signal of the reception antenna Receiving, measuring the power ratio between the transmission signal fed to the antenna under measurement and the reception signal received by the reception antenna, and a test transceiver for sequentially storing the measurement data of the power ratio for each frequency;
The measurement angle of the antenna to be measured is sequentially changed, the measurement data of the power ratio stored by the test transceiver is sequentially acquired for each measurement angle, and based on the measurement data acquired at all measurement angles. A calculator that measures the radiation characteristics of the antenna under test corresponding to each of a number of frequencies;
An antenna measuring apparatus equipped with

Furthermore, a turntable for rotating the antenna under measurement that scans the direction of the received beam;
A turntable controller for driving the turntable and measuring a rotation angle of the antenna under measurement;
A transmission antenna that radiates transmission radio waves to the antenna under measurement;
A signal processor that sequentially changes the direction of the received beam of the antenna under measurement when the rotation angle measured by the turntable controller reaches a predetermined measurement angle;
Receiving the received signal received by the antenna under measurement and feeding the transmission signal to the transmission antenna, measuring the power ratio between the received signal received by the antenna under measurement and the transmission signal fed to the transmission antenna; A test transceiver for sequentially storing the measurement data of each received beam direction for scanning,
The measurement angle of the antenna to be measured is sequentially changed, the measurement data of the power ratio stored by the test transceiver is sequentially acquired for each measurement angle, and based on the measurement data acquired at all measurement angles. A computer that measures the radiation characteristics of the antenna under measurement corresponding to each of a number of received beam directions;
It may be an antenna measuring device provided with.

According to the present invention, it is possible to simultaneously perform from a large number of beam scans to antenna pattern measurements during one rotation of the turntable. As a result, the antenna pattern measurement time for an antenna that performs a large number of beam scans can be There is an effect that can be further shortened.

Embodiment 1 FIG.
In Embodiment 1 according to the present invention, a phased array antenna will be described as an example of the antenna to be measured. The antenna to be measured includes a plurality of transmission / reception modules configured to include, for example, a phase shifter, a low noise amplifier, a high output amplifier, a transmission / reception changeover switch, and an oscillator. Each transmission / reception module is connected to an antenna element arranged one-dimensionally or two-dimensionally in a plane constituting the antenna opening surface, and radiates a transmission radio wave through the antenna element, and is reflected by an object and returned. Receives the reflected radio wave or the transmission radio wave sent from the opposite antenna. The antenna to be measured is phase-shifted by the phase shifter by the antenna control unit, and the phase of each antenna element is controlled. In the antenna measurement apparatus according to this embodiment, the antenna to be measured is mounted on a turntable, and while the antenna to be measured is rotated by the turntable, a plurality of beam scanning and measurement frequency switching are performed, and the transmission radio wave of the antenna to be measured is transmitted. Is received by a receiving horn antenna which is an opposing antenna, and the antenna pattern of the antenna to be measured is measured. Hereinafter, the antenna measurement apparatus of this embodiment will be described with reference to the drawings.

FIG. 1 shows the configuration of an antenna measurement apparatus according to Embodiment 1 of the present invention.
In FIG. 1, a computer 1 forms a control unit that controls the entire system of the antenna measurement apparatus, and is configured by a personal computer, a general-purpose computer, or the like. The turntable 2 has a servo motor, and rotates the antenna 6 to be measured attached to the rotor portion. The turntable control unit 3 measures the rotation angle (rotation table angle) of the rotor unit of the turntable 2 using an angle detector (not shown) such as a rotary encoder or resolver, and controls the servo motor of the turntable 2. Drive to control the rotation of the antenna 6 to be measured. The turntable I / F 4 monitors turntable angle data measured by the turntable control unit 3 and outputs a measurement angle trigger signal based on the turntable angle data.

  The beam scanning processor 5 is a signal processor for setting the phase of the antenna 6 to be measured and performing beam forming and beam scanning. The beam scanning processor 5 includes a digital signal processor, a logic circuit, a PLD circuit, and the like, and can execute predetermined logic operations and control sequences at high speed. The test transceiver 7 transmits and receives RF (Electromagnetic Wave = Radio Frequency) signals. A GPIB (General Purpose Interface Bus) cable 8 connects the computer 1 and the turntable control unit 3 and exchanges control signals (commands) and measurement data between the two. The control cable 9 connects between the turntable 2 and the turntable control unit 3. A LAN cable 10 connects the computer 1 and the turntable I / F 4. A LAN cable 11 connects the computer 1 and the beam scanning processor 5. The control cable 12 connects the beam scanning process 5 and the antenna 6 to be measured. The control cable 13 connects the turntable controller 3 and the turntable I / F 4. The control cable 14 connects the turntable I / F 4 and the beam scanning processor 5. The control cable 15 connects the beam scanning processor 5 and the test transceiver 7. The GPIB cable 16 connects the computer 1 and the test transceiver 7. The RF cable 17 is connected to the RF output port of the test transceiver 7 and transmits an RF signal.

  The first RF port of the directional coupler 18 is connected to the RF cable 17. The directional coupler 18 has three ports, distributes and outputs the RF signal input to the first RF port via the RF cable 17 to the second RF port, and also inputs the RF signal input from the first RF port. The signal is distributed and output to the third RF port. The power distribution ratio is appropriately set according to the radio wave environment of each antenna and the performance of the test transceiver 7. The RF cable 19 is connected to the second RF port of the directional coupler 18. The RF cable 23 is connected to the third RF port of the directional coupler 18.

  Reference numeral 20 indicates a beam (transmitted radio wave) transmitted from the antenna 6 to be measured. The horn antenna 21 is a counter antenna for reception disposed opposite to the antenna 6 to be measured. The horn antenna 21 receives the beam 20 transmitted from the antenna to be measured 6. The RF cable 22 connects between the monitor receiver A port of the test transceiver 7 and the horn antenna 21. The RF cable 23 connects the reference receiver R port of the test transceiver 7 and the directional coupler 18.

Next, the operation of the antenna measurement apparatus according to Embodiment 1 will be described.
FIG. 2 is a sequence diagram showing a procedure for performing antenna pattern measurement while scanning a beam in the first embodiment. With reference to FIG. 3, the operation of the antenna measuring apparatus configured as described above will be described.

  First, the computer 1 sets a beam scanning list for performing beam scanning for the beam scanning processor 5 via the LAN cable 11 (step S1). The beam scanning list provides phase information for setting the phase of each antenna element by controlling the phase shifter so that the antenna 6 to be measured forms a desired beam, and should perform antenna pattern measurement. For each beam pattern, phase information corresponding to the pattern is provided. Here, a case where phase information corresponding to N (N ≧ 2) beam patterns is given to the beam scanning list will be described as an example. The beam pattern differs depending on the beam directing direction and the beam shape, and depending on the configuration of the phased array antenna, it is possible to give a beam pattern of about 100 patterns. By switching a plurality of types of beam patterns, for example, switching between a broad beam and a narrow beam and switching of the beam directing direction can be performed.

  Next, the computer 1 sends a command to the test transceiver 7 via the GPIB cable 16 to start RF transmission of an arbitrary frequency (step S2).

  Next, the computer 1 sets measurement angle specifications (measurement start angle, measurement end angle, measurement step angle) on the turntable I / F 4 via the LAN cable 10 (step S3). The measurement angle specifications may be set in advance, or the measurement angle specifications may be changed and set as appropriate according to the antenna 6 to be measured.

  Next, the computer 1 sends a command for instructing rotation start to the turntable control unit 3 via the GPIB cable 8. Thereby, the turntable control unit 3 decodes the received command, and starts rotation of the turntable 2 in accordance with the decoded control program (step S4).

  Information on the turntable angle of the turntable 2 is always transmitted from the turntable control unit 3 to the turntable I / F 4 via the control cable 13. Thereafter, the rotor unit of the turntable I / F 4 performs step rotation at a predetermined measurement step angle θd interval between the measurement start angle θ0 and the measurement end angle θn based on the set measurement angle specifications. Measurement will be performed sequentially.

  Next, in the turntable I / F 4, it is determined whether or not the turntable angle has reached the planned measurement angle, and the turntable 2 is rotated until it is detected that the measurement angle has been reached (step S5). . When it is detected that the measurement angle has been reached, a measurement angle trigger signal is output from the turntable I / F 4 to the beam scanning processor 5 via the control cable 14 (step S6). At this time, the measurement angle θi at the time of the i-th step rotation is given by θi = θ0 + i × θd. The measurement step angle θd is, for example, in units of 0.1 degrees.

  Next, the beam scanning processor 5 reads phase information from the beam scanning list for the beam pattern at the head of the beam scanning list, and performs beam setting for the antenna 6 to be measured based on the read phase information (step S7). . At this time, phase information for setting the beam is transmitted from the beam scanning processor 5 to the antenna to be measured 6 via the control cable 12, and the phase shifter is controlled based on this phase information, and the antenna to be measured 6 is measured. Beam scanning is performed.

  Next, a measurement trigger signal is output from the beam scanning processor 5 to the test transceiver 7 via the control cable 15 (step S8).

  Next, antenna pattern measurement is performed in the test transceiver 7 (step S9). In the antenna pattern measurement, in order to cancel the fluctuation of the RF output of the test transceiver 7, the average power (A) of the RF signal input to the monitor receiver A via the RF cable 22 and the RF cable 23 are used. Then, a ratio measurement with the average power (R) of the RF signal input to the reference receiver R is performed. Here, A / R is obtained as the power ratio. The test transmitter / receiver 7 sequentially stores the measurement data of the power ratio A / R in the memory in association with each beam pattern. The power A indicates the average power of the reception signal of the horn antenna 21, and the power R indicates the average power of the transmission signal transmitted from the test transceiver 7 and distributed by the directional coupler 18.

When the measurement is completed, a measurement completion trigger signal is output from the test transceiver 7 to the beam scanning processor 5 via the control cable 15 (step S10). When the beam scanning processor 5 has not completed beam scanning of all the beam patterns in the beam scanning list, the antenna to be measured 6 is sequentially sequentially only for the beam patterns for which beam scanning has not been completed on the beam scanning list. Beam setting is performed. After beam scanning is performed in the set state, antenna pattern measurement by the test transceiver 7 is repeated.
Thus, the antenna pattern measurement in the test transmitter / receiver 7 is repeatedly performed from the beam setting until there is no beam pattern for which beam scanning is not completed on the beam scanning list. At this time, for example, when the beam scanning of each antenna pattern is completed, the beam scanning processor 5 sets a beam scanning management flag each time.

  The beam scanning processor 5 confirms whether or not the beam scanning is completed on the beam scanning list by confirming the presence or absence of the beam scanning management flag (step S11). Further, by counting the number of beam scanning management flags, the number of completed beam scanning can be confirmed.

  The computer 1 starts monitoring the status of the test transceiver 7 via the GPIB cable 16 after the measurement is started. When it is confirmed that the state of the test transceiver 7 is complete, the computer 1 instructs the test transceiver 7 to transfer data. Upon receiving the data transfer instruction, the test transceiver 7 measures the power ratio A / R measured for each beam pattern and stored in the memory of the test transceiver 7 via the GPIB cable 16 for each beam pattern. The measurement data associated with the angle (θi) is collectively transferred (step S12). This measurement data is composed of a pair of a code number (C) for identifying the type of beam pattern and a power ratio value (A / R) measured corresponding to the beam pattern. Stored in memory.

  Here, it is determined whether or not the turntable angle information of the turntable 2 measured by the turntable control unit 3 has reached the measurement end angle (step S13). As a result of the determination, if the turntable angle information has not reached the measurement end angle, the computer 1 returns to step S5 described above, and executes a series of operations shown in S5 to S13 for each measurement step angle. When the turntable angle information of the turntable 2 reaches the measurement end angle, the computer 1 sends a command for instructing the end of rotation (rotation stop) to the turntable control unit 3 via the GPIB cable 8. (Step S14).

  After receiving the command for instructing the end of rotation, the turntable controller 3 decodes the received command and stops the turntable 2 according to the decoded control command information. Next, the computer 1 sends a command for stopping the RF transmission to the test transceiver 7 via the GPIB cable 16, and stops the RF transmission of the test transceiver 7 (step S15).

  Further, the computer 1 receives the measurement data associated with all the measurement angles from the test transceiver 7 and then, for each code number (C) for identifying the type of the beam pattern stored in the memory, the computer 1 An antenna pattern is obtained based on the value of the power ratio A / R corresponding to (θi). This antenna pattern shows the characteristics of power distribution or electric field strength with respect to an angle (for example, azimuth angle or depression angle) around the antenna directivity axis, and the measurement angle corresponds to the angular resolution that allows pattern measurement in that angular direction. To do.

  As described above, in the antenna measurement apparatus according to the first embodiment, while the turntable 2 rotates, the antenna to be measured 6 is scanned by a certain number of times in the beam scanning list, so that a large number of antenna patterns can be simultaneously formed. Thus, the time required for antenna pattern measurement can be reduced to 1 / (N-1) times that of the prior art, where N is the number of beam patterns to be switched. When the time required for individual pattern measurement in the beam pattern is sufficiently smaller than the measurement time for each measurement step angle as described later).

Next, the time transition within the measurement angle trigger cycle in the first embodiment will be further described.
FIG. 3 is a time chart showing the operation within the measurement angle trigger cycle. For example, when an antenna pattern is measured every angular resolution of 0.1 degree, the measurement angle trigger period T1 is inevitably short when the measurement step angle is extremely small. In order to carry out from the measurement of the power ratio A / R to the measurement data transfer within this short T1 time, until the completion of all beam scanning, a computer 1 having a GPIB with a low control speed as an interface is involved in the control. I try not to. That is, the speed of antenna pattern measurement is realized by exchanging discrete signals directly between the beam scanning processor 5 and the test transceiver 7 without using the GPIB cable or the computer 1.

  Here, N is the number of beam scans for switching the beam pattern, T2 is the time until the beam is set from the beam scanning processor 5 to the antenna 6 to be measured, and the measurement time of the power ratio A / R in the test transceiver 7 Is T3, and the time for transferring data from the test transceiver 7 to the computer 1 is T4. In this case, if the sum of the beam setting time T2 and the measurement time T3 is multiplied by the number of beam scans N and the data transfer time T4 is added, [N × (T2 + T3) + T4] is less than the measurement angle trigger period T1, Each antenna pattern measurement by switching a large number (N) of beam patterns can be realized.

FIG. 4 is an example of antenna pattern measurement in the first embodiment. FIG. 4 shows an example in which an antenna pattern is measured at a predetermined measurement step angle while scanning three directivity beams as an example of switching three beam patterns. FIGS. 4A and 4B show the states at the measurement start time and halfway, and the beams 20-1, 20-2, and 20-3 show three beam patterns scanned in a time division manner.
As shown in FIG. 4, in FIG. 4A, the power ratio A / R of all beams at the measurement start time is measured. For example, the beam 20-3 has a beam pointing direction of 30 °, the beam 20-2 has a beam pointing direction of 0 °, and the beam 20-1 has a beam pointing direction of −30 °. At this time, each beam has a power ratio distribution as shown in FIG. In FIG. 4B, the power ratio A / R of all the beams at the midpoint is measured. For example, the beam 20-2 has a beam directing direction of 0 °, the beam 20-1 has a beam directing direction of −30 °, and the beam 20-3 has a beam directing direction of an angle of 30 °. At this time, each beam has a power ratio distribution as shown in FIG. FIG. 4E is a diagram in which the distribution of the power ratio at each measurement angle is plotted for the beam 20-1 based on the distribution of the power ratio at each measurement angle shown in FIGS. 4C and 4D. It is. In the example of the figure, a diagram in which −60 °, −30 °, 0 °, 30 °, and 60 ° are typically plotted is shown. By narrowing this angle interval to a predetermined measurement step angle (for example, 0.1 °) interval, it is possible to obtain antenna pattern characteristics as indicated by a curve indicated by reference numeral 200 in FIG. In addition, antenna patterns can be similarly measured for the other beams 20-2 and 20-3. Thus, by obtaining the power ratio A / R of each beam pattern at each measurement angle as the antenna 6 to be measured rotates, the power ratio distribution for each beam pattern, that is, the antenna pattern characteristics can be obtained. .

  As described above, conventionally, the antenna pattern is measured by rotating the turntable 2 as many times as the number of antenna patterns that need to be measured. However, according to the antenna measuring apparatus of the present embodiment, it is possible to collectively perform a number of beam scans to antenna pattern measurement while rotating the turntable 2 once, resulting in antenna pattern measurement time. There is an effect that can be shortened compared to the prior art.

Embodiment 2. FIG.
FIG. 5 is a diagram showing the configuration of the antenna measurement apparatus according to Embodiment 2 of the present invention.
In this embodiment, it is assumed that the antenna to be measured is an aperture antenna that can perform frequency modulation without requiring beam scanning. In FIG. 5, the antenna to be measured 6 includes an antenna and an amplifier, and is used as various antennas such as a phased array antenna, a single beam antenna, and a monopulse antenna. The computer 1 forms a control unit that controls the entire system of the antenna measurement apparatus, and is configured by a personal computer, a general-purpose computer, or the like. The turntable 2 has a servo motor, and rotates the antenna 6 to be measured attached to the rotor portion. The turntable control unit 3 measures the rotation angle (rotation table angle) of the rotor unit of the turntable 2 using an angle detector (not shown) such as a rotary encoder or resolver, and controls the servo motor of the turntable 2. Drive to control the rotation of the antenna 6 to be measured. The turntable I / F 4 monitors turntable angle data measured by the turntable control unit 3 and outputs a measurement angle trigger signal based on the turntable angle data.

  The beam scanning processor 5 activates frequency sweep measurement for the test transceiver 7. The beam scanning processor 5 may control the beam scanning of the antenna 6 to be measured. The test transceiver 7 transmits and receives RF (electromagnetic wave = Radio Frequency) signals while modulating the transmission frequency. A GPIB (General Purpose Interface Bus) cable 8 connects the computer 1 and the turntable control unit 3 and exchanges control signals (commands) and measurement data between the two. The control cable 9 connects between the turntable 2 and the turntable control unit 3. A LAN cable 10 connects the computer 1 and the turntable I / F 4. A LAN cable 11 connects the computer 1 and the beam scanning processor 5. The control cable 12 connects the beam scanning processor 5 and the antenna 6 to be measured. The control cable 13 connects the turntable controller 3 and the turntable I / F 4. The control cable 14 connects the turntable I / F 4 and the beam scanning processor 5. The control cable 15 connects the beam scanning processor 5 and the test transceiver 7. The GPIB cable 16 connects the computer 1 and the test transceiver 7. The RF cable 17 is connected to the RF output port of the test transceiver 7 and transmits an RF signal.

  The first RF port of the directional coupler 18 is connected to the RF cable 17. The directional coupler 18 distributes and outputs the RF signal input to the first RF port via the RF cable 17 to the second RF port, and also outputs the RF signal input from the first RF port to the third RF port. Distributed output to the RF port. The power distribution ratio is appropriately set according to the radio wave environment of each antenna and the performance of the test transceiver 7. The RF cable 19 is connected to the second RF port of the directional coupler 18. The RF cable 23 is connected to the third RF port of the directional coupler 18.

  Reference numeral 20 indicates a beam (transmitted radio wave) transmitted from the antenna 6 to be measured. The horn antenna 21 receives the beam 20 transmitted from the antenna to be measured 6. The RF cable 22 connects between the monitor receiver A port of the test transceiver 7 and the horn antenna 21. The RF cable 23 connects the reference receiver R port of the test transceiver 7 and the directional coupler 18.

Next, the operation of the antenna measurement apparatus according to the second embodiment will be described.
FIG. 6 is a sequence diagram showing a procedure for performing antenna pattern measurement while switching the measurement frequency in the second embodiment. With reference to FIG. 6, the operation of the antenna measuring apparatus configured as described above will be described.

  First, the computer 1 instructs the beam scanning processor 5 to start frequency sweep measurement via the LAN cable 11. If the antenna 6 to be measured is an antenna capable of beam scanning, the computer 1 performs a beam scanning list for performing beam scanning on the beam scanning processor 5 via the LAN cable 11 as in the first embodiment. Set. The beam scanning processor 5 instructs the test transceiver 7 to start frequency sweep measurement (step S21).

Next, the computer 1 sets a frequency sweep list in the test transceiver 7 via the GPIB cable 16. The frequency sweep list is stored in the storage device of the test transceiver 7. Next, the computer 1 sends a command for starting RF transmission to the test transceiver 7 via the GPIB cable 16 to start RF transmission of an arbitrary frequency (step S22).
Here, the frequency sweep list includes information on set frequencies to be measured when the antenna pattern is measured by sequentially switching the oscillation frequency of the test transceiver 7 and performing frequency sweep. At this time, a frequency sweep list may be set in advance in the ROM of the test transceiver 7.
Subsequently, the computer 1 sets measurement angle specifications (measurement start angle, measurement end angle, measurement step angle) in the turntable I / F 4 via the control cable 14 (step S23). The measurement angle specifications may be set in advance, or the measurement angle specifications may be changed and set as appropriate according to the antenna 6 to be measured.

  Next, the computer 1 sends a command for instructing rotation start to the turntable control unit 3 via the GPIB cable 8. Thereby, the turntable control unit 3 decodes the received command, and starts rotation of the turntable 2 in accordance with the decoded control program (step S24).

  Information on the turntable angle of the turntable 2 is always transmitted from the turntable control unit 3 to the turntable I / F 4 via the control cable 13. Thereafter, the rotor unit of the turntable I / F 4 performs step rotation at a predetermined measurement step angle θd interval between the measurement start angle θ0 and the measurement end angle θn based on the set measurement angle specifications. Measurement will be performed sequentially.

  Next, in the turntable I / F 4, it is determined whether or not the turntable angle has reached the planned measurement angle, and the turntable 2 is rotated until it is detected that the measurement angle has been reached (step S25). . When it is detected that the measurement angle has been reached, a measurement angle trigger signal is output from the turntable I / F 4 to the frequency sweep processor 50 via the control cable 14 (step S26). At this time, the measurement angle θi at the time of the i-th step rotation is given by θi = θ0 + i × θd. The measurement step angle θd is, for example, 0.1 degree.

  Next, the test transceiver 7 reads information on the set frequency to be measured at the head of the frequency sweep list stored in the storage device. The test transceiver 7 sets the oscillation frequency of the oscillator based on the read frequency information, modulates the transmission frequency, and transmits the frequency-modulated transmission signal (RF signal) to the antenna 6 to be measured via the RF cable 17. Send.

  Next, a measurement trigger signal is output from the beam scanning processor 5 to the test transceiver 7 via the control cable 15 (step S27).

  Next, antenna pattern measurement is performed in the test transceiver 7 (step S28). In the antenna pattern measurement, in order to cancel the fluctuation of the RF output of the test transceiver 7, the average power (A) of the RF signal input to the monitor receiver A via the RF cable 22 and the RF cable 23 are used. Then, a ratio measurement with the average power (R) of the RF signal input to the reference receiver R is performed. Here, A / R is obtained as the power ratio. The measured data is stored in the memory of the test transceiver 7 in association with the set frequency. The power A indicates the average power of the reception signal of the horn antenna 21, and the power R indicates the average power of the transmission signal transmitted from the test transceiver 7 and distributed by the directional coupler 18.

When the measurement is completed, a measurement completion trigger signal is output from the test transceiver 7 to the beam scanning processor 5 via the control cable 15 (step S29). In the test transmitter / receiver 7, when the switching of all the set frequencies in the frequency sweep list is not completed, the frequency switching is sequentially performed only for the frequencies for which the frequency sweep is not completed on the frequency sweep list.
For example, the test transceiver 7 reads information on the next set frequency in the frequency sweep list, and switches the oscillation frequency of the oscillator based on the read frequency information. The test transceiver 7 sends a modulated transmission signal (RF signal) to the antenna 6 to be measured via the RF cable 17. The power ratio measurement is repeated from the frequency setting in the test transmitter / receiver 7 until there is no set frequency for which the frequency sweep has not been completed on the frequency sweep list. The test transceiver 7 sets a frequency sweep completion flag for the beam scanning processor 5 when all frequencies are switched and the power ratio measurement at each set frequency is completed.

  The beam scanning processor 5 confirms whether or not the frequency sweep is completed on the frequency sweep list by confirming the presence or absence of the frequency sweep completion flag (step S30).

  The computer 1 starts monitoring the status of the test transceiver 7 via the GPIB cable 16 after the measurement is started. When it is confirmed that the state of the test transceiver 7 is the completion of the frequency sweep, the computer 1 instructs the test transceiver 7 to transfer data. Upon receiving the data transfer instruction, the test transmitter / receiver 7 associates the power ratio A / R, which is measured for each beam pattern and stored in its own memory, with the measurement angle to the computer 1 via the GPIB cable 16. The measured data is transferred as a batch (step S31). This measurement data is configured as a pair of a code number for identifying the type of beam pattern and the value of the power ratio measured corresponding to the set frequency, and is stored in the memory of the computer 1.

  Here, in the computer 1, it is determined whether or not the turntable angle information of the turntable 2 measured by the turntable control unit 3 has reached the measurement end angle (step S32). As a result of the determination, if the turntable angle information has not reached the measurement end angle, the computer 1 returns to step S25 described above, and executes a series of operations shown in steps S25 to S32 for each measurement step angle. When the turntable angle information of the turntable 2 reaches the measurement end angle, the computer 1 sends a command for instructing the end of rotation (rotation stop) to the turntable control unit 3 via the GPIB cable 8. (Step S33).

  After receiving the command for instructing the end of rotation, the turntable controller 3 decodes the received command and stops the turntable 2 according to the decoded control command information. Next, the computer 1 sends a command for stopping the RF transmission to the test transceiver 7 via the GPIB cable 16 (step S34), and stops the RF transmission of the test transceiver 7.

  In addition, the computer 1 receives the measurement data associated with all the measurement angles from the test transceiver 7 and then, for each code number (C) that identifies the type of the set frequency stored in the memory, the computer 1 An antenna pattern is obtained based on the value of the power ratio A / R corresponding to (θi). This antenna pattern shows the characteristics of power distribution or electric field strength with respect to an angle (for example, azimuth angle or depression angle) around the antenna directing axis, and the measurement angle corresponds to the angular resolution of that angle.

  Thus, in the antenna measurement apparatus according to Embodiment 1, it is possible to simultaneously acquire a large number of antenna patterns by switching the measurement frequency in the antenna 6 to be measured a plurality of times while the turntable 2 rotates. The time required for antenna pattern measurement can be shortened as compared with the prior art.

  FIG. 7 shows a time chart within the measurement angle trigger period in the second embodiment of the present invention. For example, if the measurement step angle is extremely small, such as when an antenna pattern is measured every angular resolution of 0.1 degree, the period T1 of the measurement angle trigger is inevitably short. Within this short T1 time, it is necessary to carry out from antenna pattern measurement to measurement data transfer at multiple frequencies. Until the switching of all frequencies is completed, a discrete signal is exchanged between the beam scanning processor 5 and the test transceiver 7 so that the computer 1 having a GPIB with a low control speed as an interface does not intervene in the control. By doing so, the speed of antenna pattern measurement is realized.

  Here, the number of set frequencies to be measured is N, the frequency switching frequency at the test transceiver 7 is T2, the measurement time at the test transceiver 7 is T3, and the data is sent from the test transceiver 7 to the computer 1 When the transfer time is T4, if the value [N × (T2 + T3) + T4], which is obtained by multiplying the measurement time T3 by the number of frequency switching N and the data transfer time T4, is less than the measurement angle trigger period T1, It can be confirmed from the figure that a number of frequency switching to measurement can be realized.

  FIG. 8 is a diagram illustrating an example of an antenna pattern in the second embodiment. FIG. 8 shows an example in which an antenna pattern is measured while switching three frequencies. FIGS. 8A and 8B show the states at the measurement start time and midway, and 20-1, 20-2 and 20-3 show three beams whose frequencies are switched in a time division manner. is there.

  As described above, conventionally, the antenna pattern was measured by rotating the turntable 2 by the number of frequencies required to be acquired. However, according to the antenna measurement apparatus of the second embodiment, the turntable It is possible to carry out a number of frequency switching to antenna pattern measurement while rotating 2 twice, and as a result, the antenna pattern measurement time can be shortened as compared with the prior art.

  Incidentally, in the first embodiment, as an example in which the antenna to be measured 6 is a phased array antenna, an example is shown in which an antenna pattern is measured by scanning a plurality of beam directivity angles at one frequency. In the example of the first embodiment, a frequency sweep list is set in the test transmitter / receiver 7 as in the second embodiment, and the frequency of the antenna 6 to be measured is controlled so as to rotate the antenna 6 to be measured once. In the meantime, each antenna pattern can be measured by scanning a plurality of beam directivity angles at a plurality of frequencies.

  Also, it is not a matter of course that it can be used when measuring antenna patterns of antennas other than phased array antennas and aperture antennas.

  Of course, in the first and second embodiments, the case where the transmission antenna pattern of the antenna 6 to be measured is measured has been described as an example. However, the reception antenna pattern is measured by changing the RF path. Needless to say, it can be used. A simple example is given below.

  In FIG. 1, for example, the antenna under measurement 6 that scans the reception beam direction is used so that the beam scanning processor 5 can perform beam scanning by switching the reception beam direction of the antenna under measurement 6. In addition, the antenna to be measured 6 is rotated by the turntable 2 using the horn antenna 21 which is an opposing antenna as a transmission antenna. The turntable controller 3 drives the turntable 2 and measures the rotation angle of the antenna 6 to be measured.

  The test transceiver 7 feeds a transmission signal to the horn antenna 21, and a transmission radio wave is radiated from the horn antenna 21 toward the antenna 6 to be measured. Thereafter, when the rotation angle measured by the turntable control unit 3 reaches a predetermined measurement angle, the beam scanning processor 5 sequentially changes the reception beam direction of the antenna 6 to be measured. The antenna under measurement 6 receives the transmission radio wave from the horn antenna 21, and the test transceiver 7 measures the power ratio between the reception signal received by the antenna under measurement 6 and the transmission signal fed to the horn antenna 21. The test transceiver 7 sequentially stores the power ratio measurement data in the memory for each reception beam direction to be scanned. When the beam scanning is completed (for the entire scanning range), the test transceiver 7 transmits the stored power ratio measurement data to the computer 1, and the computer 1 stores the transmitted data in the memory. Thus, the computer 1 sequentially changes the measurement angle of the antenna 6 to be measured at predetermined measurement step angle intervals, and sequentially acquires the measurement data of the power ratio stored by the test transceiver 7 for each measurement angle. ,Remember. Here, when the computer 1 detects that the measurement of the power ratio at all measurement angles is completed, the reception sensitivity characteristics of the antenna 6 to be measured respectively corresponding to a large number of reception beam directions based on the stored measurement data. (Receiving antenna pattern characteristics) may be obtained.

  Further, in the second embodiment, an oscillator is provided in the antenna to be measured 6 and, instead of modulating the transmission frequency by the test transceiver 7, the transmission frequency is modulated by the antenna to be measured 6 and the frequency sweep is performed. You may do it.

It is a block diagram which shows Embodiment 1 of this invention. FIG. 3 is a sequence diagram showing a measurement procedure in the first embodiment. 4 is a timing chart within a measurement angle trigger cycle in the first embodiment. FIG. 3 is a diagram illustrating an example of a beam pattern in the first embodiment. It is a block diagram which shows Embodiment 2 of this invention. FIG. 11 is a sequence diagram showing a measurement procedure in the second embodiment. 10 is a timing chart within a measurement angle trigger cycle in the second embodiment. It is a figure which shows the antenna pattern example of the to-be-measured antenna 6 at the time of measuring the antenna pattern in Embodiment 2. FIG.

Explanation of symbols

  1 computer, 2 turntable, 3 turntable control unit, 4 turntable I / F, 5 beam scanning processor, 6 antenna to be measured, 7 test transceiver, 8 GPIB cable, 9 control cable, 10 LAN cable, 11 LAN cable, 12 control cable, 13 control cable, 14 control cable, 15 control cable, 16 GPIB cable, 17 RF cable, 18 directional coupler, 19 RF cable, 21 horn antenna (opposing antenna), 22 RF cable, 23 RF cable.

Claims (1)

The measured antenna that allows beam scanning a phase shifter, a turntable for rotating,
A turntable controller for driving the turntable and measuring a rotation angle of the antenna under measurement;
A receiving antenna that is disposed opposite to the antenna under measurement and that receives a transmission radio wave radiated from the antenna under measurement;
While the rotation angle measured by the turntable control unit is within a predetermined angle range, every time the rotation angle measured by the turntable control unit sequentially reaches the predetermined measurement angle, a measurement angle trigger signal is sequentially output. A turntable interface unit,
When a measurement angle trigger signal is received from the turntable interface unit while the turntable is rotating, a predetermined number of phases set in the phase shifter of the antenna to be measured are sequentially changed, and the antenna to be measured is A signal processor that scans the predetermined number of beams ;
Measure the power ratio by feeding the transmission signal to the antenna under measurement and receiving the reception signal from the reception antenna, measuring the power ratio between the transmission signal fed to the antenna under measurement and the reception signal received by the reception antenna. A test transceiver for sequentially storing data for each scanned beam ;
For each measured angle of the measuring antenna, and collectively acquired measurement data stored power ratio by the test transceiver for the number of the predetermined number of beams, which are sequentially obtained at all measurement angle measurement A computer for measuring the radiation characteristics of the antenna under measurement corresponding to each of a number of beam patterns based on the data;
An antenna measurement device comprising:

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