JP2005223429A - Retrodirective antenna system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a retrodirective antenna system capable of suppressing transmission of unnecessary waves by sufficiently eliminating noise included in a pilot signal. <P>SOLUTION: A mixer 12 mixes a received pilot signal with a first local oscillation signal to apply frequency conversion to the pilot signal into a first low frequency signal. A multiplier 18 filters a multiplied first low frequency signal. Part of an output of a voltage-controlled oscillator 15 is mixed with a second local oscillation signal to generate a second low frequency signal, the phase of which is compared with the phase of the 1st low frequency signal subjected to multiplication and filtering. The output of a phase comparator 19 is given to the voltage-controlled oscillator 15 and a high frequency transmission signal is generated. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a retrodirective antenna device used for transmission / reception of a direction detection and communication interference radio system such as a radar, and a microwave power transmission device of a space solar power generation satellite.

  Japanese Laid-Open Patent Publication No. 6-327172 describes a conventional retrodirective power transmission device. According to Japanese Patent Laid-Open No. 6-327172, phase information of a received pilot signal is detected by a band pass filter, a pre-phase detector, and a phase detector, and an angle of the pilot signal is calculated by an arithmetic processing unit computer based on the detected phase information. Then, the microwave is transmitted in the direction of the pilot signal by controlling the variable phase shifter of the transmission system. The transmitted microwave has a configuration obtained by frequency-converting a pilot signal with a multiplier and a frequency mixer.

  Also, “Retrodirective Antenna Systems for Wireless Communications”, Communication Networks and Services Conference May 152003, p. 20-23 discloses a heterodyne retrodirective antenna device. According to this document, a received signal received by an antenna is down-converted by a local signal, and further up-converted to have the same frequency as that of the received signal. A phase conjugate transmission signal is transmitted in the direction of the reception signal.

JP-A-6-327172

“Retrodirective Antenna Systems for Wireless Communications”, Communication Networks and Services Conference May 152003, p. 20-23.

  In the conventional retrodirective power transmission device disclosed in Patent Document 1, a pilot signal and a doubled wave of the pilot signal are mixed by a frequency mixer to generate a high-frequency signal having the same frequency as the pilot signal obtained by phase conjugation. Used as a signal, the source signal is multiplied by 3 to obtain a transmission signal. For this reason, for example, in a case where a pilot signal is sent from a power base on the earth to a solar power generation satellite arranged in outer space, and power is transmitted to the power base by a retrodirective power transmission device mounted on the solar power generation satellite, When the pilot signal becomes weak and the C / N of the received signal is extremely low, the C / N of the transmitted signal also decreases depending on the C / N of the received signal, and other frequencies using frequencies near the transmitted signal are used. There was a problem of causing interference to the radio system.

  In addition, in the conventional heterodyne retrodirective antenna device disclosed in Non-Patent Document 1, the frequency of the reception signal and the transmission signal is the same, so the circuit configuration of this device is the frequency of the reception signal and the transmission signal. However, there is a problem that it cannot be used for retrodirective antenna devices having different frequencies. In addition, in the heterodyne method disclosed in Non-Patent Document 1, in order to remove the (RF + 2 × IF) frequency signal from the combined signal of the RF frequency signal generated after up-conversion and the (RF + 2 × IF) frequency signal, The frequency of the IF signal must be increased to some extent, the frequency of the received IF signal after down-conversion becomes high, and there is a problem that unnecessary waves can not be sufficiently removed by the low-pass filter in the upstream stage of the up-converter.

  The present invention has been made in order to solve the above-described problems. It is an object of the present invention to obtain a retrodirective antenna device that can sufficiently remove noise contained in a pilot signal and suppress transmission of unnecessary waves. Objective.

  The retrodirective antenna device according to the first aspect of the present invention receives a pilot signal by an array antenna in which a plurality of transmitting element antennas and receiving element antennas are arranged in an array, and transmits an RF transmission signal in the direction of the pilot signal. In the retrodirective antenna apparatus, a first mixer that converts a pilot signal from the receiving element antenna into a first low-frequency signal by a first local oscillation signal, and the RF transmission signal for the frequency of the pilot signal A frequency multiplier that multiplies the first low-frequency signal and a part of the RF transmission signal extracted from the RF transmission signal is converted into a second low-frequency signal by the second local oscillation signal. A second mixer, a phase comparator for comparing the phase of the multiplied first low-frequency signal and the second low-frequency signal; Is input the output signal of the phase comparator, in which a phase locked loop having a voltage controlled oscillator for generating the RF transmission signal to the voltage controlled oscillator.

  A retrodirective antenna device according to a second aspect of the present invention receives a pilot signal by an array antenna in which a plurality of transmitting element antennas and receiving element antennas are arranged in an array, and transmits an RF transmission signal in the direction of the pilot signal. In the retrodirective antenna apparatus, the pilot signal from the receiving element antenna is frequency-converted to a first low-frequency signal by a first local oscillation signal, and the pilot signal for the frequency of the RF transmission signal is converted. A frequency divider that divides the first low-frequency signal by a ratio to the frequency, and a part of the RF transmission signal extracted from the RF transmission signal is converted into a second low-frequency signal by the second local oscillation signal. A second mixer for frequency conversion, a phase comparator for phase comparison of the divided first low-frequency signal and the second low-frequency signal, The oscillating output signal is an input voltage controlled phase comparator is obtained a phase locked loop having a voltage controlled oscillator for generating the RF transmission signal.

  A retrodirective antenna device according to a third aspect of the invention is the retrodirective antenna device according to the first or second aspect of the invention, wherein the first and second local oscillation signals are generated by a voltage controlled oscillator, Each of the first and second local oscillation signals is extracted and divided, and the divided signals are phase-compared with the output of the original oscillator, and the phase comparison output is input to the voltage controlled oscillator. It is a thing.

  A retrodirective antenna device according to a fourth aspect of the invention is the retrodirective antenna device according to the first or second aspect of the invention, wherein the second local oscillation signal is phase-adjusted by a phase shifter and the second Is input to the mixer.

  A retrodirective antenna device according to a fifth aspect of the present invention is the retrodirective antenna device according to the first or second aspect of the present invention, wherein an in-phase pilot signal is input to each of the receiving element antennas from the front direction of the array antenna. The transmission element antennas are adjusted to transmit in-phase RF transmission signals.

  According to the first to third aspects of the invention, the received pilot signal is converted to a low frequency by the first local oscillation signal and filtered, and a high frequency transmission signal is generated by the phase locked loop. The noise contained in the RF transmission signal transmitted from can be suppressed.

  According to the invention described in claim 4 or claim 5, the phase shift of the local oscillation signal in the retrodirective antenna device is adjusted by the phase shifter, so that variations in the passage phase caused by factors such as manufacturing errors are corrected. Then, the RF transmission signal can be beam-transmitted in a desired direction.

Embodiment 1

  A retrodirective antenna device according to Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is a configuration diagram of a retrodirective antenna device according to Embodiment 1 of the present invention. In FIG. 1, 1 is a receiving element antenna for receiving a pilot signal, 2 is a transmitting element antenna for transmitting an RF transmission signal, and these are arranged in an array. The RF input signal uses various element antennas such as patches, horns, slots, and coils for each element antenna. Reference numeral 3 denotes an RF module that receives a pilot signal received by the receiving element antenna 1 and generates a signal to be transmitted from the transmitting element antenna 2, and is provided for each set of the receiving element antenna 1 and the transmitting element antenna 2. FIG. 1 shows RF modules # 1 to #n. The circuit configuration of the RF module #n is the same as that of the RF module # 1. Reference numeral 4 denotes an original vibrator, and reference numeral 5 denotes a first frequency conversion circuit (hereinafter referred to as a frequency conversion circuit 5) that generates a first local oscillation signal by performing high-frequency conversion on the output signal of the original vibrator 4. Reference numeral 6 denotes a second frequency conversion circuit (hereinafter referred to as a frequency conversion circuit 6) that generates a second local oscillation signal by high-frequency conversion of the output signal of the oscillator 4. Reference numeral 7 denotes a distribution circuit that distributes the first local oscillation signal generated by the frequency conversion circuit 5, and reference numeral 8 denotes a distribution circuit that distributes the second local oscillation signal generated by the frequency conversion circuit 6. A phase shifter 9 adjusts the phase of the second local oscillation signal distributed by the distribution circuit 8 and input to each RF module. This phase shifter 9 may be set based on a phase setting command from the control circuit, or has a line length variable mechanism or the like like a phase trimmer and is adjusted by an operator. Also good. In the RF module 3, 10 is a band-pass filter, 11 is a low-noise amplifier, 12 is a first signal that converts the pilot signal output from the low-noise amplifier 11 into a first low-frequency signal by a first local signal. The mixer (hereinafter referred to as a mixer 12). A multiplier 13 multiplies the first low-frequency signal from the mixer 12 by the ratio of the frequency of the pilot signal to the frequency of the RF output signal. Reference numeral 14 denotes a band-pass filter, which filters the first low-frequency signal that is the output of the multiplier 13. A voltage controlled oscillator 15 generates an RF transmission signal to be transmitted from the transmission element antenna 2. Reference numeral 16 denotes a high-power amplifier that amplifies the RF transmission signal generated by the voltage-controlled oscillator 15 and outputs it to the transmission element antenna 2. Reference numeral 17 denotes a coupler that extracts a part of the output of the voltage controlled oscillator 15, and reference numeral 18 denotes a second low-frequency signal that converts a part of the RF transmission signal extracted by the coupler 17 into a second low-frequency signal by the second local oscillation signal. 2 mixers (hereinafter referred to as mixer 18). A phase comparator 19 compares the phase of the output of the bandpass filter 14 (ie, the multiplied first low frequency signal) with the output of the mixer 18 (ie, the second low frequency signal) to generate a voltage. Output as a value. A low-pass filter 20 is a loop filter of a phase-locked loop including the voltage-controlled oscillator 15, the coupler 17, the mixer 18, the phase comparator 19, and the low-pass filter 20. In the frequency conversion circuit 5, reference numeral 21 denotes a voltage controlled oscillator, which generates a first local oscillation signal. Reference numeral 22 denotes a coupler that extracts a part of the signal generated by the voltage controlled oscillator 21, and reference numeral 23 denotes a frequency divider that divides the signal extracted by the coupler 22. Reference numeral 24 denotes a phase comparator that compares the phases of the output signal of the frequency divider 23 and the output signal of the original oscillator 4 and outputs the result as a voltage value. Reference numeral 25 denotes a low-pass filter, which is a loop filter of a phase-locked loop including the voltage-controlled oscillator 21, the coupler 22, the frequency divider 23, the phase comparator 24, and the low-pass filter 25. In the frequency conversion circuit 6, reference numeral 26 denotes a voltage controlled oscillator, which generates a second local oscillation signal. Reference numeral 27 denotes a coupler that extracts a part of the signal generated by the voltage controlled oscillator 26, and reference numeral 28 denotes a frequency divider that divides the signal extracted by the coupler 27. Reference numeral 29 denotes a phase comparator that compares the phases of the output signal of the frequency divider 28 and the output signal of the original oscillator 4 and outputs the result as a voltage value. A low-pass filter 30 is a loop filter of a phase-locked loop including a voltage-controlled oscillator 26, a coupler 27, a frequency divider 28, a phase comparator 29, and a low-pass filter 30.

  Next, the operation of this retrodirective antenna device will be described. The radio wave transmitted from the counterpart device of the retrodirective antenna device is received by the receiving element antenna 1 as a pilot signal. The received pilot signal is mixed with a noise signal in a propagation path or the like, and is filtered by the band pass filter 10 and amplified by the low noise amplifier 11. The pilot signal amplified by the low noise amplifier 11 is mixed with the first local oscillation signal by the mixer 12 and converted into a first low frequency signal. In the mixer 12, the received pilot signal (Fr) and the first local oscillation signal (F1) are mixed and frequency-converted to a difference frequency signal (F1-Fr). The multiplier 13 multiplies the first low-frequency signal, which is the output of the mixer 12, to a frequency N1 times. For example, if the frequency of the pilot signal is 3.85 GHz and the frequency of the first local oscillation signal output from the distributor 7 is 3.85 GHz + 30 MHz, the frequency of the low-frequency signal output by the mixer 12 is 30 MHz. If the multiplication number of the multiplier 13 is N1 = 1.5, the multiplied first low-frequency signal output from the multiplier 13 is 45 MHz. Here, the frequency of the multiplier 13 is set to a ratio of the frequency of the RF transmission signal to 5.775 GHz with respect to the frequency of the pilot signal of 3.85 GHz, where the frequency of the RF transmission signal output from the transmission element antenna is 5.775 GHz. Yes. The output of the multiplier 13 is input to the band pass filter 14 and filtered. The noise included in the pilot signal is filtered in the high frequency band by the band pass filter 10, but the pass band width of the band pass filter 10 has a high center frequency and cannot be narrowed, or an attempt is made to narrow the band. This increases the cost. The pass band width of the band-pass filter 14 allows the first low-frequency signal multiplied by a low center frequency to pass therethrough, so that it can be a narrow band. The bandpass filter 14 can sufficiently cut noise contained in the pilot signal. Here, a crystal filter can be used for the band pass filter 14 in order to obtain a narrower band pass characteristic. The frequency band in which the crystal filter can be used is approximately several hundred MHz or less. If the frequency of the output signal of the multiplier 13 is about 45 MHz as described above, a crystal filter can be used as the bandpass filter 14. In other words, in order to reduce noise by using a narrow band filter such as a crystal filter for the band pass filter 14, the first low frequency signal is about 10 MHz to 100 MHz (preferably about several tens of MHz). The first local oscillation signal output from the distribution circuit 7 is set. In the actual circuit, the multiplication number N1 = 1.5 in the multiplier 13 may be configured by a combination of a multiplier with a multiplication factor of 3 and a frequency divider with a frequency divider of 2. The combination is also included in the multiplier 13 shown in the first embodiment.

  The voltage controlled oscillator 15 generates an RF transmission signal, and the coupler 17 extracts a part of the RF transmission signal. The RF transmission signal taken out by the coupler 17 is mixed with the second local oscillation signal by the mixer 18 and converted into a second low frequency signal. In the mixer 18, the RF transmission signal (Ft) and the second local oscillation signal (F2) are mixed and frequency-converted to a difference frequency signal (Ft−F2). The phase comparator 19 compares the phase of the second low-frequency signal and the multiplied first low-frequency signal output from the bandpass filter 14 and outputs a voltage value. The output of the phase comparator 19 is input to the voltage controlled oscillator 15 via the low pass filter 20. A circuit including the voltage controlled oscillator 15, the coupler 17, the mixer 18, the phase comparator 19, and the low-pass filter 20 forms a phase-locked loop circuit, and the low-pass filter 20 is a loop filter of this phase-locked loop. For example, when the first low-frequency signal is 30 MHz as described above and a 45-MHz signal is output as the low-frequency signal multiplied by the band-pass filter 14, the second low-frequency signal is second with respect to the RF transmission signal 5.775 GHz. If the frequency of the local oscillation signal is set to 5.775 GHz-45 MHz, the output signal of the mixer 18 becomes 45 MHz. The RF transmission signal output from the voltage controlled oscillator 15 is amplified by the high output amplifier 16 and transmitted from the transmission element antenna 2.

  FIG. 2 is a schematic diagram showing noise suppression in the RF module 3. FIG. 2A shows noise suppression by the loop band characteristic of the phase-locked loop circuit including the voltage controlled oscillator 15, the coupler 17, the mixer 18, the phase comparator 19, and the low-pass filter 20, and the signal indicated by the dotted line is a solid line. The signal shown by is improved. FIG. 2B shows noise suppression by a band-pass filter 14 having a narrow band pass characteristic such as a crystal filter, and a loop of a phase locked loop circuit in which a signal indicated by a dotted line is suppressed to a signal indicated by a one-dot chain line. In addition to the effect of the band characteristics, the signal shown by the solid line is improved by the band-pass filter 14 having a narrower band. If the RF transmission signal can be narrowed as shown in FIG. 2B, interference with other wireless communication systems existing in the vicinity of the transmission frequency can be suppressed.

  Next, the operation in the frequency conversion circuits 5 and 6 will be described. In the frequency conversion circuit 5, the voltage controlled oscillator 21 generates a first local oscillation signal, and a part of the first local oscillation signal is extracted by the coupler 22. The output of the coupler 22 is frequency-divided by the frequency dividing number N2 in the frequency divider 23 and input to the phase comparator 24. On the other hand, the output signal from the oscillator 4 is divided into two, one output signal is input to the phase comparator 24, and the other output signal is input to the phase comparator 29. The phase comparator 24 compares the phases of the input signal from the frequency divider 23 and the input signal from the local oscillator 4 and outputs the result as a voltage value. The output signal of the phase comparator 24 is input to the voltage controlled oscillator 21 via the low pass filter 25. A circuit including the voltage controlled oscillator 21, the coupler 22, the frequency divider 23, the phase comparator 24, and the low-pass filter 25 constitutes a phase-locked loop circuit, and the low-pass filter 25 serves as a loop filter of the phase-locked loop. Yes. For example, when a 10 MHz signal is output from the oscillator 4, the frequency dividing number of the frequency divider 23 may be N2 = 388 (the frequency of the first local oscillation signal output from the voltage controlled oscillator 21 is 3). .85 GHz + 30 MHz).

  In the frequency conversion circuit 6, the voltage controlled oscillator 26 generates a second local oscillation signal, and a part of the second local oscillation signal is extracted by the coupler 27. The output of the coupler 27 is divided by the frequency dividing number N3 in the frequency divider 28 and input to the phase comparator 29. The phase comparator 29 compares the phases of the input signal from the frequency divider 28 and the input signal from the original oscillator 4 and outputs a voltage value. The output signal of the phase comparator 29 is input to the voltage controlled oscillator 26 via the low pass filter 30. A circuit including the voltage controlled oscillator 26, the coupler 27, the frequency divider 28, the phase comparator 29, and the low-pass filter 30 forms a phase-locked loop circuit, and the low-pass filter 30 serves as a loop filter of the phase-locked loop. Yes. For example, when a 10 MHz signal is output from the oscillator 4, the frequency dividing number of the frequency divider 28 may be N3 = 573 (the frequency of the second local oscillation signal output from the voltage controlled oscillator 26 is 5). .775 GHz-45 MHz).

  The first local oscillation signal and the second local oscillation signal generated by the frequency conversion circuits 5 and 6 are input to the distribution circuit 7 and the distribution circuit 8, respectively. A first local oscillation signal is input from the distribution circuit 7 to the mixers 12 in # 1 to #n of the RF module 3. Further, the second local oscillation signal is input from the distribution circuit 8 to the mixers 18 in # 1 to #n of the RF module 3 via the phase shifter 9.

  The phase relationship will be described. In the mixer 12, the received pilot signal (Fr) and the first local oscillation signal (F1) are mixed and frequency-converted into a difference frequency signal (F1-Fr). In the multiplier 18, an RF transmission signal corresponding to the pilot signal is transmitted. Is multiplied by N1, which is a frequency ratio of the frequency, and this is frequency-converted to the frequency of the RF transmission signal in a phase-locked loop (phase-locked loop including the voltage controlled oscillator 15). Is a phase conjugate relationship. FIG. 3 is a schematic diagram illustrating a case where an RF transmission signal is transmitted in the reception direction of the pilot signal. In FIG. 3, the path difference between the reception signals of adjacent RF modules 3 is Δdr, and the path difference between the transmission signals is Δdt. When Δdr = Δdt for this path difference, if an RF transmission signal that is phase conjugate with the pilot signal is transmitted in each of # 1 to #n of the RF module 3, the RF transmission signal is in the reception direction of the pilot signal. Sent. In order to set Δdr = Δdt for the path difference, in each RF module 3, the receiving element antenna 1 and the transmitting element antenna 2 are arranged at the same point, or the receiving element antenna 1 and the transmitting antenna 2 are arranged alternately (FIG. 3). In some cases).

  Specifically, in order for the pilot signal and the RF transmission signal to have a phase conjugate relationship as described above, the pass phase of the first local oscillator signal and the pass phase of the second local oscillator signal are compared in phase. It is necessary to arrange them in relation to the lengths of the lines that propagate in the units 19. However, in practice, it is difficult to align these passing phases, and the pilot signal and the RF transmission signal are out of phase conjugation due to variations in the passing phase of the feedback path in the PLL circuit. It becomes a state. The state in which this phase shift occurs occurs in each of the # 1 to #n of the RF module 3. The phase shifter 9 adjusts a phase shift from the phase conjugate state of the RF transmission signal generated in each of the # 1 to #n of the RF module 3, and is between the distribution circuit 8 and the mixer 18 in FIG. Although provided, it may be provided between the distribution circuit 7 and the mixer 12. In order to adjust the phase shift from the phase conjugate state of the RF transmission signal generated in each of # 1 to #n of the RF module 3, for example, a pilot signal from the front direction of the array antenna including the reception element antenna 1 and the transmission element antenna 2 And the phase shifter 9 may be adjusted so that one of the RF transmission signals on the array antenna is a reference signal and the reference signal and other transmission signals are in phase. By this adjustment, it is possible to correct the variation in the passing phase caused by factors such as manufacturing errors in the circuit, and to transmit the RF transmission signal in a desired direction.

Embodiment 2

A retrodirective antenna apparatus according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 4 is a configuration diagram of a retrodirective antenna device according to Embodiment 2 of the present invention. In FIG. 4, reference numeral 31 denotes a frequency divider that divides the first low-frequency signal by the ratio of the frequency of the pilot signal to the frequency of the RF transmission signal. In FIG. 4, parts denoted by the same reference numerals as those in FIG. 1 indicate parts equivalent to or equivalent to those parts in FIG. In FIG. 4, the frequency and frequency division number of each exemplified signal are changed from those in FIG. 1 according to the frequency of the pilot signal and the frequency of the RF transmission signal.

  The retrodirective antenna apparatus according to Embodiment 2 considers the case where the frequency of the pilot signal received by the receiving element antenna 1 is higher than the frequency of the RF transmission signal transmitted by the transmitting element antenna 2, and in this case The first low-frequency signal output from the mixer 12 is divided by the frequency divider 31. The frequency division number N4 set in the frequency divider 31 is a value of the ratio of the frequency of the pilot signal to the frequency of the RF transmission signal. By setting the frequency division number in this way, the RF transmission signal is phased into the pilot signal. Can be conjugated. Note that the noise contained in the pilot signal can be suppressed in the RF module 3 and the phase adjustment using the phase shifter 9 can be performed in the same manner as those described in the first embodiment. In FIG. 4, the frequency division number N4 = 1.5 in the frequency divider 31 is configured by a combination of a frequency divider of 3 and a frequency multiplier of 2 in an actual circuit. However, a combination of such combinations is also included in the frequency divider 31 shown in the second embodiment.

1 is a configuration diagram of a retrodirective antenna device according to Embodiment 1 of the present invention. FIG. 3 is a schematic diagram showing noise suppression in the RF module 3. FIG. It is a schematic diagram which shows the case where RF transmission signal is transmitted in the receiving direction of a pilot signal. It is a block diagram of the retrodirective antenna device concerning Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reception element antenna 2 Transmission element antenna 4 Original oscillator 9 Phase shifter 12 1st mixer 13 Multiplier 15 Voltage controlled oscillator 18 2nd mixer 19 Phase comparator 21 Voltage controlled oscillator 26 Voltage controlled oscillator 31 Frequency divider

Claims (5)

In a retrodirective antenna device that receives a pilot signal by an array antenna in which a plurality of transmitting element antennas and receiving element antennas are arranged in an array and transmits an RF transmission signal in the direction of the pilot signal, A first mixer that converts a pilot signal into a first low-frequency signal using a first local signal, and a ratio of the frequency of the RF transmission signal to the frequency of the pilot signal, A multiplier for multiplying, a second mixer for frequency-converting a part of the RF transmission signal extracted from the RF transmission signal into a second low-frequency signal by a second local oscillation signal, and the multiplied first low-frequency signal A phase comparator for phase comparison of the frequency signal and the second low frequency signal, and an output signal of the phase comparator is input, and voltage-controlled oscillation is performed to Retrodirective antenna apparatus characterized by comprising a phase locked loop having a voltage controlled oscillator for generating a transmission signal. In a retrodirective antenna device that receives a pilot signal by an array antenna in which a plurality of transmitting element antennas and receiving element antennas are arranged in an array and transmits an RF transmission signal in the direction of the pilot signal, The first low-frequency signal is a ratio of a first mixer that converts a pilot signal to a first low-frequency signal by a first local signal and a frequency of the pilot signal with respect to the frequency of the RF transmission signal. A second frequency divider for frequency-converting a part of the RF transmission signal extracted from the RF transmission signal into a second low-frequency signal by a second local oscillation signal, and the frequency division A phase comparator that compares the phase of the first low-frequency signal with the second low-frequency signal, and an output signal of the phase comparator is input to perform voltage-controlled oscillation to generate the R Retrodirective antenna apparatus characterized by comprising a phase locked loop having a voltage controlled oscillator for generating a transmission signal. The first and second local oscillation signals are generated by a voltage-controlled oscillator, and a part of each of the first and second local oscillation signals is extracted and divided, and the divided signals are generated as original signals. 3. The retrodirective antenna device according to claim 1, wherein the phase comparison is made with an output of a vibrator and the phase comparison output is inputted to the voltage controlled oscillator. 3. The retrodirective antenna device according to claim 1, wherein the second local oscillation signal is phase-adjusted by a phase shifter and input to the second mixer. 4. The in-phase pilot signal is input to each receiving element antenna from the front direction of the array antenna, and the in-phase RF transmission signal is adjusted to be transmitted from each transmitting element antenna. The retrodirective antenna device according to 2.

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