JPH03102902A - Limiter for microwave receiver - Google Patents

Abstract

PURPOSE:To obtain a limiter ensuring isolation and coping with a broad band input signal by suppressing a received microwave signal with a limiter diode and applying branching and synthesizing waves with a directional coupler to plural diodes. CONSTITUTION:A received microwave signal (gain 50dB) from a microwave antenna is inputted to a terminal Tin and given to a PIN diode 11, in which the gain is reduced to 25dB. Then, a hybrid 12 branches the signal at the rate of the attenuation quantities between a detection diode (attenuation 7dB) and a PIN diode (attenuation 25dB) 13b. The one branched signal is detected by a diode 13a and the other signal is isolated by a diode 13b. Then each threshold level of the diodes 11, 13b is decreased based on a DC voltage obtained by the detection of the diode 13a to make the entire isolation complete. Then, the signals branched at the rate are synthesized at a hybrid 14 in the same ratio and the result is outputted from a terminal Tout.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to a limiter device for a microwave receiver that suppresses excessive power contained in a received microwave signal and protects a microwave signal processing section provided at a subsequent stage, and particularly relates to Regarding a limiter device for a microwave receiver that can provide sufficient isolation (excessive power suppression) for wideband received microwave signals with a simple configuration, The purpose of this invention is to obtain a limiter device for a microwave receiver that can handle input signals of A limiter device for a microwave receiver that suppresses excessive power contained in a microwave signal received by the microwave antenna to a certain value or less includes a limiter diode that suppresses excessive power contained in a microwave signal received by the microwave antenna to a certain value; a first directional coupler connected to the output side and splitting the input microwave signal into a plurality of parts; and a first directional coupler connected in parallel to the output side of the first directional coupler and splitting the plurality of split input microwave signals. a plurality of diodes corresponding to the plurality of diodes, and a second directional coupler that multiplexes each output microwave signal of the plurality of diodes, and a limiter diode and a second directional coupler that combines the output microwave signals of the plurality of diodes. reflected by
The structure is designed to protect the microwave signal processing section.

[Industrial application field]

The present invention relates to a limiter device for a microwave receiver that suppresses excessive power contained in a received microwave signal and protects a microwave signal processing section provided at a subsequent stage, and particularly relates to a limiter device for a microwave receiver that suppresses excessive power contained in a received microwave signal and protects a microwave signal processing section provided at a subsequent stage. The present invention relates to a limiter device for a microwave receiver that is capable of providing sufficient isolation (excessive power suppression) for a microwave receiver.

In recent years, microwave communication systems have been attracting particular attention as the information society progresses, as they can be used as multiplex communication, transmitting from hundreds of lines to hundreds of thousands of times at the same time on a single frequency radio wave. The above Microwave Communication Act requires a limiter device for the microwave receiver in order to protect the receiver from excessive input in general high-power calendar equipment that shares transmitting and receiving antennas or radar equipment that has a highly sensitive receiver. Is required.

Various limiter devices for the microwave receivers mentioned above are being developed, such as TR tubes using gas discharge and PIN diodes using semiconductors, but PIN diodes are particularly popular due to their high speed, constant quality, and long life. It is becoming widely used due to its characteristics. A limiter device for a PIN diode microwave receiver having various characteristics is required to ensure sufficient so-called isolation to sufficiently suppress transmission power leakage and external excessive power.

[Conventional technology]

Conventionally, there have been limiter devices for this type of microwave receiver as shown in FIGS. 4 to 6.

FIG. 4 above shows a circuit configuration diagram of a limiter device of a conventional microwave receiver. In the same figure, the limiter device of a conventional microwave receiver has an input terminal on the microwave antenna (not shown) side. A pre-stage that is connected in parallel to the transmission line (strip line in the case of a microwave integrated circuit) of T1 and ground terminal T2, and suppresses the excessive power contained in the microwave signal received by the microwave antenna to a constant value. and a resistor 22 connected in parallel to the output side of the preceding stage PIN diode 21 and acting as feedback and bias for DC voltage by a detection diode 25a, which will be described later, and a resistor 22 connected to the output side of the resistor 22. , a coupler 23 that extracts a part of the received microwave signal by electromagnetically coupling to the transmission line;
an RF amplifier 24 that amplifies the signal extracted at step 3;
A detection diode 25a that detects the signal amplified by the RF amplifier 24, and a detection diode 25a and a P in the previous stage.
Each output signal of the IN diode 21 is inputted, and the configuration includes a subsequent PIN diode 26 that suppresses excessive power contained in the input signal to a constant value.

Next, the operation of the conventional device based on the above configuration will be explained. First, when the microwave signal received by the microwave antenna is input between the input terminals T1 and T2, the PIN diode 21 in the previous stage
is excited by the power of the input microwave signal and becomes short-circuited, and by reflecting this microwave signal, the output to the receiving side is suppressed to a predetermined constant value.

Further, a part of the suppressed microwave signal is taken out by the coupler 23, amplified by the RF amplifier 24, and then detected by the detection diode 25a. This detection diode 25
The DC voltage component obtained by the detection of a is the PI of the previous stage.
By being superimposed on the output microwave signal of the N diode 21, the threshold level of the PrN diode 26 at the subsequent stage is lowered. Moreover, it is configured to maximize the isolation of microwave signals input to the PIN diodes 21 and 26 at the front and rear stages.

Further, the above-mentioned FIG. 5 shows a circuit configuration diagram of another conventional limiter device of a microwave receiver, and in the same figure, the other conventional microwave reception protection device has a PIN diode 21 in the previous stage like the conventional device. , subsequent PIN diode 26
It is constructed by adding a detection diode 25b that extracts and detects a part of the output side signal of the PIN diode 26 at the subsequent stage, and a DC amplifier 27 that amplifies the output of the detection diode 25b.

Other conventional devices based on the above structure are each PI in the front and rear stages.
The threshold level is adjusted by detecting the outputs of the N diodes 21 and 26, amplifying the detected DC current, and performing feedback control.

Furthermore, the above-mentioned FIG. 6 shows a circuit configuration diagram of a limiter device of another conventional microwave receiver, and in the same figure, the limiter device of another conventional microwave receiver includes a PIN diode 29 and a detection diode 25c. are connected in parallel, and the spacing between each PIN diode 29 and the detection diode 25c on the transmission line is λ/4.

Another conventional device based on the above structure is a detection diode 25c.
The threshold level of the PIN diode 29 is lowered by the detection voltage of the detection diode 25c.
It is possible to obtain sufficient overall isolation by also utilizing the isolation provided by .

[Problem to be solved by the invention]

Since the limiter device of each conventional microwave receiver is constructed as described above, each of the conventional devices shown in FIGS. 4 and 5 above requires a separate coupler, RF amplifier, or DC amplifier. Therefore, the circuit configuration becomes complicated, and furthermore, a PIN diode must be added separately for wide-band input microwave signals.

In addition, although the other conventional device shown in FIG. 6 has a simple circuit structure, the attenuation of the detection diode is about 5 to 8 dB, so overall isolation is sufficient. In addition, there was a problem in that another diode had to be added in order to widen the band.

The present invention has been made to solve the above-mentioned conventional problems, and provides a limiter device for a microwave receiver that can ensure sufficient isolation with a simple circuit structure and can handle wideband input signals. The purpose is to

[Means to solve the problem]

FIG. 1 is a diagram explaining the principle of the present invention.

In the same figure, a limiter device for a microwave receiver according to the present invention is provided between a microwave antenna and a microwave signal processing section, and is configured to limit excessive power contained in a signal received by the microwave antenna to a certain value. A limiter device for a microwave receiver to be suppressed as described below includes a limiter diode 1 for suppressing excessive power contained in a microwave signal received by the microwave antenna to a certain value or less, and a limiter diode 1 connected to the output side of the limiter diode l. , a first directional coupler 2 that splits an input microwave signal into a plurality of parts; and a first directional coupler 2 that is connected in parallel to the output side of the first directional coupler 2 and corresponds to the plurality of split input microwave signals. It is equipped with a plurality of diodes 3 and a second directional coupler 4 that multiplexes each output microwave signal of the plurality of diodes 3, and combines the excessive power of the received microwave signal with the limiter diode 1 and the plurality of The configuration is such that it is reflected by the diode 3 and protects the microwave signal processing section.

[Effect]

According to the present invention, a limiter diode in the first stage suppresses a microwave signal to a certain value or less, and a directional coupler demultiplexes the input signal to each of the diodes to a plurality of diodes in the second stage. By combining the microwave signals with a directional coupler again, the threshold level of each diode can be lowered with a simple configuration, ensuring sufficient isolation over a wide range of frequencies. It becomes possible.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on FIG. 2.

FIG. 2 shows a circuit configuration diagram of the device of this embodiment, and in the figure, the limiter device of the microwave receiver according to this embodiment suppresses the excessive power contained in the microwave signal received by the microwave antenna to a constant value. PIN diode 1 suppresses
a hybrid l2 connected to the output side of the PIN diode 11, which splits the input microwave signal into two signals at a predetermined ratio and acts as a directional coupler;
A detection diode 13a that detects one signal branched by the hybrid {2 and outputs a DC current, and a PIN diode 13b that suppresses excessive power contained in the other signal branched by the hybrid 12. The signals separated by the hybrid 12, detected by the detection diode 13a, and having excessive power suppressed by the PIN diode 13b are combined at the same ratio as the predetermined ratio of the hybrid 12, and the direction is determined. This configuration includes a hybrid 14 that acts as a sexual coupler.

Next, the operation of the apparatus of this embodiment based on the above configuration will be explained together with its effects. First, the received microwave signal from the microwave antenna is transmitted to the terminal T. Assume that the input microwave signal has a gain of 50 dB. This microwave signal with a gain of 50 dB is reduced to 25 dB by the PIN diode 11 (with an attenuation amount of 25 dB). Further, the hybrid 12 demultiplexes the signal at a rate corresponding to the ratio of the attenuation of the detection diode 13a (assuming an attenuation of 7 dB) and the PIN diode 13b (assuming an attenuation of 25 ciB).

One signal branched by the hybrid 12 is detected by a detection diode 13a, and the other signal is isolated by a PIN diode 13b. The PIN is determined based on the DC voltage obtained by the detection of the detection diode 13a.
By lowering the respective threshold levels of the diodes 11 and 13b, the overall isolation can be made complete.

Furthermore, the signals demultiplexed at the above ratio are multiplexed at the same ratio as the ratio at the hybrid 15 and output from the terminal T.

Out Next, the above embodiment device is connected to a microwave integrated circuit (hereinafter referred to as MI
FIG. 3 shows a perspective view of the circuit configured as C).

In the same figure, MIC boards 31 and 32 are placed on a carrier 30.
, 33 are arranged, and bypass capacitors 34, 36, 40, 44 are arranged on the MIC boards 31, 32, 33.
, 47, PIN diode 35, 41, detection diode 39, pattern resistor 37, 45, 46, hybrid 3
8, 42, and a grounding ribbon 43 are each connected by a slit-top line.

The microwave signal input to the hybrid 38 from the strip line is demultiplexed at a demultiplexing ratio corresponding to the electromagnetic coupling gap of the hybrid 38.

The separated microwave signals are input to the detection diode 39 and the PIN diode 41, respectively, where they are detected and isolated. The microwave signal reflected by the detection diode 39 and the PIN diode 41 is reversely input to the hybrid 38 , and from the hybrid 38 is passed through a branch strip line to a 50Ω pattern resistor 37 and a bypass capacitor 36 . absorbed and the above PIN diode 35
It shall not affect the

Furthermore, each microwave signal from the detection diode 39 and the PIN diode 4l is input to the hybrid 42 and multiplexed at the same ratio as the splitting ratio of the hybrid 38.

In addition, in the above embodiment, two hybrids 12,
The two diodes connected between 14 and 14 were composed of a detection diode 13a and a PIN diode 13b.
The two diodes can also be configured together as a detection diode.

Further, in the above embodiment, two hybrids 12, 1
Although the microwave signal is split into two signals and multiplexed in 4, it is also possible to split the microwave signal into any number of signals greater than or equal to two. In this case, an arbitrary number of detection diodes and PIN diodes are connected.

Furthermore, although the above embodiment is configured as a microwave integrated circuit, it may also be configured with a microwave transmission line or circuit element such as a conductor pipe system or a coaxial system without being integrated.

〔Effect of the invention〕

As explained above, according to the present invention, the limiter diode in the previous stage suppresses the microwave signal to a certain value or less, and the input signal to each of the diodes is demultiplexed by the directional coupler to the plurality of diodes in the latter stage. Since we have adopted a structure in which each of the demultiplexed microwave signals is multiplexed again using a directional coupler, the threshold level of each diode can be lowered with a simple configuration, making it possible to use a wide band of frequencies. On the other hand, this has the effect of ensuring sufficient isolation.

[Brief explanation of drawings]

Fig. 1 is a diagram explaining the principle of the present invention, Fig. 2 is a configuration diagram of an embodiment of the present invention, Fig. 3 is a circuit perspective diagram when an embodiment of the device of the present invention is a microwave integrated circuit, and Fig. 4 6 to 6 show configuration circuit diagrams of conventional devices. 1... Limiter diode 2... First directional coupler 3... Multiple diodes 4... Second directional coupler 11 13b, 21, 26, 29... PIN diode 12, 14...Hybrid 1 3 a, 2 5 a, 2 5 b, 2
5 c-...Detection diode 23...Coupler Kuzu 4 times 27 Capture button O, also 0 my 7U signal reception right (Oriyan Sota 1 (place O times F E town Shigeru S 5 times stupid 6 times

Claims (2)

[Claims] 1. In a limiter device for a microwave receiver that is provided between a microwave antenna and a microwave signal processing section and suppresses excessive power contained in a signal received by the microwave antenna to a certain value or less, the microwave A limiter diode (1) that suppresses excessive power contained in the microwave signal received by the antenna to below a certain value; 1 directional coupler (
2) and connected in parallel to the output side of the first directional coupler (2),
A plurality of diodes (3) corresponding to the plurality of split input microwave signals, and a second directional coupler (4) for multiplexing each output microwave signal of the plurality of diodes (3). , reflecting the excessive power of the received microwave signal by a limiter diode (1) and a plurality of diodes (3);
A limiter device for a microwave receiver, which protects a microwave signal processing section. 2. The plurality of diodes (3) are configured with a detection diode for signal detection and a PIN diode for suppressing excessive power contained in the signal, and the first 2. The limiter device for a microwave receiver according to claim 1, wherein the second directional coupler performs demultiplexing and multiplexing.