JP2011166272A - Transceiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transceiver for suppressing return power from an antenna to a receiver through an isolator without providing circulators in multiple stages. <P>SOLUTION: The transceiver includes: a transmitter; a receiver; a circulator which is connected to the output end of the transmitter and the input end of the receiver, respectively, and separates transmission output and reception power; a transmission system directional coupler connected between the output end of the transmitter and the circulator; a reception system directional coupler connected between the input end of the receiver and the circulator; and a phase shifter connected between the coupling terminal of the transmission system directional coupler and the coupling terminal of the reception system directional coupler. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a transceiver that transmits or receives microwave or millimeter-wave high-frequency signals.

  Conventionally, another circulator is provided between the input terminal of the receiver and the circulator, and the return power from the transmitter to the receiver is monitored by a diode limiter to control the operation of the transmitter and to the receiver. A receiver protection circuit that suppresses excessive input is known (see, for example, Patent Document 1).

Japanese Utility Model Publication No. 5-43633

  Part of the power output from the transmitter to the antenna is reflected by the antenna, input to the circulator, and returns to the receiver. When the electrical length between the circulator and the antenna changes due to movement of the antenna or the like, the magnitude of the return power from the antenna via the circulator to the receiver changes. A part of the power input from the transmitter to the circulator is input to the receiver as leakage power. The return power and leakage power input to the receiver increase as the power of the transmitter increases, which affects the performance and life of the receiver. For this reason, it is necessary to increase the power durability of the receiver and to suppress excessive return power and leakage power from the antenna to the receiver.

  The conventional receiver protection circuit disclosed in Patent Document 1 requires a circulator provided in multiple stages, so that there is a problem that the parts cost is increased and the circuit size is increased. Further, there is a problem that NF (Noise Figure) is deteriorated due to signal loss in a circulator provided in front of the input terminal of the receiver.

  The present invention has been made to solve such a problem, and to obtain a transceiver capable of suppressing return power and leakage power to a receiver via a circulator without providing circulators in multiple stages. With the goal.

  A transceiver according to the present invention includes a transmitter, a receiver, a circulator connected to an output end of the transmitter and an input end of the receiver, respectively, for separating transmission output and received power, and an output end of the transmitter And a transmission system directional coupler connected between the circulator, a receiving system directional coupler connected between the input end of the receiver and the circulator, and a coupling terminal of the transmission system directional coupler And a phase shifter connected between the coupling terminals of the receiving system directional coupler.

  According to the present invention, a directional coupler and a phase shifter are provided between a transmitter and a receiver, and by supplying antiphase power from the transmitter to the receiver, the receiver via the circulator at the time of transmission is provided. Return power and leakage power can be suppressed.

It is a figure which shows the structure of the transmitter / receiver by Embodiment 1 which concerns on this invention. It is a figure which shows the suppression effect of the return electric power from the antenna via a circulator to a receiver by Embodiment 1. FIG.

Embodiment 1 FIG.
1 is a diagram showing a configuration of a transceiver according to Embodiment 1 of the present invention.
In the figure, the transceiver includes a circulator 2, a transmission directional coupler 3, a transmitter 4, a phase shifter 5, a reception directional coupler 6, a switch 7, and a receiver 8. I have. The circulator 2 has 3 terminals. The first terminal of the circulator 2 is connected to the feeding point of the antenna 1. The second terminal of the circulator 2 is connected to the output end side of the transmitter 4. The third terminal of the circulator 2 is connected to the input end side of the receiver 8.

  A directional coupler 3 is connected between the second terminal of the circulator 2 and the output terminal of the transmitter 4. A directional coupler 6 is connected between the third terminal of the circulator 2 and the output terminal of the receiver 8. A switch 7 is connected between the output terminal of the directional coupler 6 and the receiver 8. A phase shifter 5 is connected between the directional coupler 3 and the directional coupler 6 of the receiving system. The directional coupler 3 distributes the input power to the main terminal and the coupling terminal and outputs it. The directional coupler 6 combines and outputs signals input from the main terminal and the coupling terminal. The switch 7 is composed of a high-frequency switch circuit having high power durability. The switch 7 is controlled by an external control device (not shown) and can switch the connection between the input terminal of the receiver 8 and the ground. Normally, the switch 7 is connected to the receiver 8. Note that the power loss in the switch 7 increases as the power resistance of the switch 7 increases.

Next, the operation of the transceiver according to the first embodiment will be described.
The transceiver is switched between transmission and reception in a time division manner by an external control device (not shown).
At the time of transmission, the high-frequency signal output from the transmitter 4 is input to the directional coupler 3. The directional coupler 3 divides the input high-frequency signal into two parts: a main signal output from the main terminal and a sub signal coupled to the coupling terminal. The main signal distributed to the main terminal of the directional coupler 3 is input to the second terminal of the circulator 2. The main signal input to the second terminal of the circulator 2 is transmitted as a transmission signal from the first terminal to the antenna 1, and most of the transmission signal is radiated from the antenna 1 to the space as a radio wave.
The received power received from the space by the antenna 1 during reception is input to the first terminal of the circulator 2 as a high-frequency received signal, passes through the circulator 2 and the directional coupler 6, and passes through the switch 7. 8 is received. When the reception power of the receiver 8 exceeds or is assumed to exceed the allowable power, the connection of the switch 7 is switched by an instruction from an external control device (not shown), and the switch 7 is connected to the ground. Is done.

At this time, according to the electrical length between the antenna 1 and the circulator 2, a part of the transmission signal transmitted to the antenna 1 during transmission is reflected by the antenna 1, and the reflected wave from the antenna 1 is the first of the circulator 2. , And is output from the third terminal of the circulator 2 as the return power 9 of the circulator 2. The return power 9 to the circulator 2 passes through the directional coupler 6 and the switch 7 and is input to the receiver 8.
Further, at the time of transmission, a part of the transmission signal input from the transmitter 4 to the second terminal of the circulator 2 leaks from the third terminal of the circulator 2 to the receiver 8 side as a leakage signal 10.

The return power 9 input to the first terminal of the circulator 2 and the leakage signal 10 leaking from the second terminal on the transmission side of the circulator 2 to the third terminal on the reception side are combined, and the combined signal is directionally coupled. Is input to the main terminal of the device 6.
On the other hand, the phase of the sub-signal distributed from the coupling terminal of the directional coupler 3 is adjusted by the phase shifter 5 and then input to the coupling terminal of the directional coupler 6 as the adjustment signal 11.
The directional coupler 6 combines the combined signal of the return power 9 and the leakage signal 10 input from the main terminal and the adjustment signal 11 input from the combined terminal as a combined signal 12 and outputs the combined signal 12 to the switch 7. The combined signal 12 is input to the receiver 8 via the switch 7.

At this time, the phase shifter 5 sets the phase of the adjustment signal 11 so as to be opposite to the phase of the combined signal of the return power 9 from the transmission side and the leakage signal 10 to the reception side. This set phase is preset by an external control device (not shown).
When the electrical length between the circulator and the antenna changes due to the movement of the antenna 1 or the like, the return power 9 changes according to the change in the electrical length, so the setting phase is varied according to the movable angle of the antenna 1. You may do it.

  Thus, in the directional coupler 6, the return power 9 from the transmitter 4 to the receiver 8 is suppressed by synthesizing the combined signal of the return power 9 and the leakage signal 10 and the negative phase adjustment signal 11. be able to. Further, since the return power 9 output from the transmitter 4 and returned to the receiver 8 is canceled using the adjustment signal 11 obtained by separating a part of the output power of the transmitter 4, the characteristics due to the temperature characteristics of the output of the transmitter 4 Variations can be reduced.

  Next, the effect of the transceiver according to the first embodiment will be described. Here, the operating frequency of the transmitter / receiver in FIG. 1 is an X band (for example, 10 GHz band), a 100 W transmitter 4, a circulator 2 with an isolation amount of 20 dB, a directional coupler 3 with a coupling amount of 20 dB, and a coupling amount. An embodiment in which a transceiver is configured using a 10 dB directional coupler 6, a phase shifter 5, and an antenna 1 having a VSWR (voltage standing wave ratio) of 2 will be described. FIG. 2 is a diagram illustrating the effect of suppressing the return power from the antenna to the receiver via the circulator according to the first embodiment. The calculation result graph 13 of FIG. 2 shows the effect when the directional coupler 3, the directional coupler 6, and the phase shifter 5 shown in FIG. 1 are not provided, and the calculation result graph 14 of FIG. The effect when the directional coupler 3, the directional coupler 6, and the phase shifter 5 shown in FIG.

  Here, in the case where a path composed of the directional coupler 3 having a coupling amount of 20 dB, the directional coupler 6 having a coupling amount of 10 dB, and the phase shifter 5 is not provided, the transmitter 4 depends on the electrical length between the antenna 1 and the circulator 2. The return power 9 from the receiver to the receiver 8 varies from 6 W to 19 W as shown in the calculation result graph 13 of FIG. 2 by combining the return power 9 and the leakage signal 10 from the transmission side to the reception side.

On the other hand, if the electrical length between the antenna 1 and the circulator 2 is fixed, the return power 9 from the transmission side is determined, so that this and the combined component of the signal 10 leaking from the transmission side to the reception side are canceled out. By setting the phase with the phase shifter 5, the return power to the receiver 4 can be suppressed to about 4 W as shown in the calculation result graph 14 of FIG. 2.
Even when the antenna 1 is movable, the electrical length between the antenna 1 and the circulator 2 is fixed to a known value according to the movable angle of the antenna 1, so that the set phase according to the movable angle of the antenna 1 is set. You can adjust.

  Therefore, since the transmitter / receiver according to Embodiment 1 can reduce the return power 9 from the transmission side, the power input to the receiver 8 can be further suppressed, and the power resistance of the switch 7 can be further reduced. Can do. As a result, the loss of the switch 7 can be reduced, and the reception NF of the transceiver can be reduced.

  As described above, the transmitter / receiver according to the first embodiment has a microwave transmitter / receiver configuration having a circulator that separates transmission output and received power, and a switch provided between the output terminal of the transmitter and the circulator and in front of the receiver. By providing a directional coupler between each input terminal and the circulator, connecting a phase shifter between the coupling terminals of each directional coupler, and setting the amount of phase shift appropriately, the circulator is isolated. The return power from the antenna to the receiver during transmission according to the amount can be suppressed.

  1 antenna, 2 circulator, 3 (transmission system) directional coupler, 4 transmitter, 5 phase shifter, 6 (reception system) directional coupler, 7 switch, 8 receiver.

Claims (3)

A transmitter,
A receiver,
A circulator connected to the output end of the transmitter and the input end of the receiver, respectively, for separating the transmission output and the received power;
A transmission system directional coupler connected between the output end of the transmitter and the circulator;
A receiving system directional coupler connected between the input end of the receiver and the circulator;
A phase shifter connected between a coupling terminal of the transmission system directional coupler and a coupling terminal of the reception system directional coupler;
A transceiver equipped with.   The phase shifter is phase-set so as to supply power from the transmitter to the receiver in opposite phase to the combined signal of the return power and leakage power to the receiver via the isolator. Item 1. The transceiver according to item 1.   2. The transceiver according to claim 1, further comprising a switch connected between the circulator and the input terminal of the receiver and for switching a connection between the input terminal of the receiver and the ground.

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