JPS5921508B2 - Receiver polarization characteristic measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for measuring reception polarization characteristics of an antenna, that is, elliptical polarization coefficient and tilt angle, with high precision using a phase amplitude detection method.

A conventional device of this type is shown in FIG.

In the figure, 1 is a carrier signal generation circuit including a transmitter; 2 is a carrier wave signal generation circuit including a transmitter;
is the transmission main polarization terminal, 311i transmission polarization conversion circuit,
This is for sending the transmitted wave 4 to the satellite receiving antenna 5. 6 is a satellite repeater, T is a satellite transmitting antenna,
The main polarized transmission radio wave 8 from the satellite is received by the antenna to be measured 9 .

The components of the antenna to be measured 9 are a main reflector 10, a sub-reflector 11, a primary radiator 12, a group demultiplexer 13, etc. The radio waves 8 from the satellite are also received by the polarization reference antenna 14. 15 is a polarization matching circuit, 18Cf' phase difference plate 16, 9
00 retardation plate 1? , a polarization splitter 18, and a rotary joint 19, and is installed in place of the reception polarization conversion circuit of the antenna to be measured 9 or the polarization reference antenna 14.

Reference numeral 20 denotes an amplitude detection circuit connected to the receiving terminal 10,000 of the polarization matching circuit 15.

Next, the operation will be explained.

First, the reception polarization conversion circuit (not shown) of the antenna to be measured 9 is removed, and the polarization matching circuit 15 is installed in its place. A transmission wave 4 is sent from the carrier signal generation circuit 1 to the satellite using the transmission system equipment of the antenna under test 9, and the main polarized wave is transmitted from the satellite transmission antenna T through the satellite reception antenna 5 and the star relay path 6. The signal 8 is sent out, received by the antenna to be measured 9, rotates the 180-a retardation plate 16 and the 90-a retardation plate 17 of the polarization matching circuit 15, and the output voltage of the amplitude detection circuit 20 becomes zero. Do it like this. The mechanical rotation angles of both retardation plates at that time are read, and the elliptical polarization factor of the combination of the transmission polarization characteristics of the satellite transmitting antenna 7 and the reception polarization characteristics of the antenna to be measured 9 is determined. This result is defined as the measurement value a. Next, the polarization matching circuit 15 is attached to the polarization reference antenna 14, and the main polarization signal 8 from the satellite is also received.
The 180 phase difference plate 16 and the 90 degree phase difference plate 17 are rotated so that the output voltage of the amplitude detection circuit 20 becomes zero. The mechanical rotation angles of both phase difference plates at that time are read, and the transmission polarization characteristics of the satellite transmitting antenna 7 and the polarization reference antenna 1 are read.
The elliptical polarization factor of the combination of the four reception polarization characteristics is determined. This result is defined as the measurement value b. Furthermore, the polarization reference antenna 14
After mechanically rotating 904 degrees around the antenna beam axis, similar measurements are performed to determine the elliptical polarization coefficient, which is the transmission polarization characteristic of the satellite transmitting antenna 7 and the reception polarization of the polarization reference antenna 14. A composite property with the polarity of the property reversed is required. This is defined as the measured value c. From these results, polarization reference antenna 1 is determined from measurement value b and measurement value c.
4 is removed, and the elliptical polarization coefficient measurement value d of the satellite transmitting antenna 7 can be determined. Next, the elliptical polarization coefficient measurement value e of only the antenna to be measured 9 can be obtained from the measurement value d and the measurement value a. The vector relationship between these measurements is shown in FIG. In the figure, 21 is the combined elliptical polarization measured value a of the satellite transmitting antenna 7 and the antenna to be measured 9.
It is. In addition, 22 and 23 are the combined elliptical polarization coefficients of the satellite transmitting antenna 7 and the polarization reference antenna 14, and the measured values b of Vj before and after the mechanical rotation of 90 degrees around the antenna beam axis of the polarization reference antenna 14. } and the measured value c. From the three vectors 21, 22, and 23 thus measured, first 24, which is one of the differences between 22 and 23, is found.
24 indicates the elliptical polarization coefficient of the polarization reference antenna, and 25, which is one of the sums of 22 and 23, is the elliptical polarization coefficient d of the satellite transmitting antenna.

Further, 26, which is the difference between 21 and 25, indicates the measured value e of the elliptical polarization coefficient of the antenna 9 to be measured. As mentioned above, in order to measure reception polarization characteristics using conventional equipment, it is necessary to remove the reception polarization conversion circuit, which is a part of the antenna device under test, and install the polarization matching circuit 15 there. It took a considerable amount of time to rotate the 180mm retardation plate 16 and 900 retardation plate 17 to eliminate the received cross-polarization component of the radio waves 8 from the satellite. , there is a problem with the accuracy of reading the mechanical rotation angle of the retardation plate, and in order to obtain the overall elliptic polarization factor that includes all the constituent elements of the antenna device under test.
This method had drawbacks such as low accuracy because it was necessary to vector-synthesize the value obtained through this measurement and the elliptic polarization factor of the reception polarization conversion circuit, which was measured separately.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and it receives a main polarization signal transmitted from a satellite and combines the receiving main polarization terminal output signal and the cross polarization terminal output signal. This method uses a polarization reference antenna that mechanically rotates 90 degrees around the antenna beam axis to detect the phase shift and amplitude between the antenna beams and the received polarization characteristics, which can be easily measured with high precision and in a short time. The purpose of this invention is to provide a sex measuring device.

FIG. 3 shows an embodiment of the present invention, in which reference numeral 27 denotes an antenna device to be measured, which includes a main reflector 10, a sub-reflector 11, a primary radiator 12, a group splitter 13, and a reception polarization conversion circuit 28. All antenna reception systems including

29 and 30 are orthogonal polarization reception terminals of the antenna device 27 to be measured.

Reference numeral 31 denotes a reception polarization reference antenna device comprising a polarization reference antenna 14 and a reception polarization conversion circuit 32 attached to its feeding portion.

33 and 34 are orthogonal polarization reception terminals of the reception polarization reference antenna device 31.

The configuration is such that the phase amplitude detection circuit 36 is selectively used by a changeover switch 35. A detailed configuration example of the phase amplitude detection circuit 36 is shown in FIG. 41 is a terminal connected to the main polarization receiving terminal of the antenna, 42 is a terminal connected to a cross polarization receiving terminal, 43 and 44 are receivers, 45 and 46 are frequency converters, 47 is a common local oscillator, and 48 and 49 are first intermediate frequency converters; 50 and 51 are second frequency converters; It constitutes a synchronous loop and an automatic gain control loop.

The output of the second frequency converter 51 of the cross-polarized wave component is branched into two branches, and is sent to the reference signal detector 5 by the phase detectors 56 and 57.
3 and the signal passed through the phase filter 90 and the phase filter 58.
Signals are obtained at output terminals 61 and 62 through trigrams 9 and 60. These two outputs are the X-axis component and the y-axis component of vector coordinates, the length of the vector indicates the elliptical polarization, and the vector direction indicates twice the tilt angle.
is composed of an X-Y recorder and the like. Next, the operation will be explained.

First, the phase amplitude detection circuit 36 is connected to the antenna device under test 27.
Connect to. The signal from the carrier signal generation circuit 1 is transmitted to the satellite using the transmission system equipment of the antenna device under test 27, and the main polarized wave is transmitted from the satellite transmitting antenna 7 through the satellite receiving antenna 5 and the satellite repeater 6. The signal 8 is sent out, and the signal received by the antenna device under test 27 is processed by the phase amplitude detection circuit 36 to obtain the measured zeta. This value is a composite elliptical polarization coefficient of the transmission polarization characteristic of the satellite transmitting antenna 7 and the reception polarization characteristic of the antenna device under test 27, and corresponds to the above-mentioned measured value a. Next, when the changeover switch 35 is switched and the phase amplitude detection circuit 36 is connected to the receiving polarization reference antenna device 31 and the same measurement as above is performed, the transmission polarization characteristics of the satellite transmitting antenna 7 and the antenna under test are Device 2
The elliptical polarization factor of the composite of the received polarization characteristics of 7 is determined. This corresponds to the measurement value b mentioned above. Then, after mechanically rotating the reception polarization reference antenna device 31 900 times around the antenna beam axis, the polarization characteristics obtained by performing similar measurements are the polarization characteristics of the satellite transmitting antenna 7. and the polarization characteristic of the receiving polarization reference antenna device 31 with the polarity reversed. This measurement is
This corresponds to the measurement value c described above. However, in this case, the mechanical rotation of the reception polarization reference antenna device only requires 900 rotations of the reception polarization conversion circuit 32 if the polarization characteristics of the polarization reference antenna 14 are good. Therefore,
Since the vector relationship shown in FIG. 2 is established from these three measured values, the reception polarization characteristic of only the antenna device under test 27 can be determined. In addition, in the above embodiment, one phase amplitude detection circuit 36 is switched by the changeover switch 35 for measurement, but one other phase amplitude detection circuit 36 is prepared,
It is clear that polarization measurement is possible without using the changeover switch 35. By performing electrical signal processing with high accuracy using the apparatus according to the embodiment of the present invention, it becomes possible to measure the receiving elliptical polarization of the antenna to be measured extremely accurately and in a short time.

Furthermore, it is now possible to accurately measure large-diameter antennas for high-performance satellite communications, with an axial ratio of 0.2 dB and a cross-polarization discrimination of 40 dB, which has been extremely difficult in the past.

As described above, according to the present invention, high accuracy Since it is possible to measure the elliptical polarization coefficient, it is extremely useful for determining the polarization performance of large-diameter antennas for satellite communications.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing a conventional measurement device, Fig. 2 is a vector relationship diagram when determining the elliptical polarization coefficient of only the antenna system under test from measurement results, and Fig. 3 is a measurement according to an embodiment of the present invention. FIG. 4 is a block diagram showing a detailed configuration example of a part of the measuring device of the present invention. In the figure, 1... Carrier wave reception generation circuit, 2... Transmission main polarization terminal, 3... Transmission polarization conversion circuit, 4... Transmission wave, 5... Satellite reception antenna, 6 ...Ran star repeater, 7
...Satellite transmitting antenna, 8...Main polarization transmission radio wave, 1
0... Main reflector, 11... Sub-reflector, 12... Primary radiator, 13... Group splitter, 14... Polarization reference antenna, 27... Antenna device to be measured , 28... Receiving polarization conversion circuit, 29, 30... Orthogonal polarization receiving terminal, 31... Polarization reference antenna device for reception, 32... Receiving polarization conversion circuit, 33, 34... - Orthogonal polarization receiving terminal, 35... changeover switch, 36... phase amplitude detection circuit.

Claims (1)

[Claims] 1. An antenna device under test that is equipped with an antenna and a polarization conversion circuit, receives an incoming predetermined elliptically polarized high-frequency signal, decomposes the signal into its main polarization component and cross-polarization component, and outputs the separated components. , comprising an antenna, a mechanism for rotating the beam axis of the antenna by at least 90 degrees, and a polarization conversion circuit, and receives the incoming predetermined elliptically polarized high frequency signal, and converts the received signal in a state where the beam axes are different by 90 degrees. A polarization reference antenna device that decomposes and outputs the main polarization component and cross polarization component in each, and the polarization of each antenna device is determined from the main polarization component and the cross polarization component obtained from each of the above antenna devices. a phase-amplitude detection device that measures the relationship between the phase and amplitude of a received polarized signal including wave characteristics, and the polarization reference antenna device whose beam axis is rotated by 90 degrees and the antenna device under test. A receiving polarization characteristic measuring device characterized in that the receiving polarization characteristic of the antenna device to be measured is determined from the measured values of the phase and amplitude of each signal.