JPS6110338Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a small microwave amplification device with excellent characteristics, which performs matching by connecting a unit amplifier and a passive circuit network to two output terminals of an input hybrid circuit. .

Conventionally, in a microwave amplifier using a field effect transistor (FET) or the like, as shown in FIG. The drain output side of FET 3 is connected to output terminal 5 via output matching circuit 4 similar to 2. In this case, as a characteristic of the FET, the output side impedance is relatively high and it is easy to match, whereas the input side impedance is low and it is very difficult to match in the necessary frequency band.
This tendency is particularly noticeable as the output increases.

Therefore, conventionally, as shown in FIG. 2, a pair of unit amplifiers 13 and 14 are connected between each pair of input and output terminals of two hybrid circuits 11 and 12, and an input terminal is connected to the input side of hybrid circuit 11. 10 and a non-reflection termination 15, and an output end 20 and a non-reflection termination 16 were provided on the output side of the hybrid circuit 12. In this case, the combined output of both amplifiers 13 and 14 is taken out, and the reflected waves at the input and output of each hybrid circuit 1
Since it is absorbed by the non-reflection terminations 15 and 16 of No. 1 and No. 12, the impedance of input and output is effectively improved, and a microwave amplification device with good characteristics can be obtained.

However, this method requires two unit amplifiers to obtain the same gain, and has disadvantages such as increased power consumption, larger size, and higher price, which is a problem especially when used in multiple stages. becomes.

An object of the present invention is to provide a small-sized microwave amplification device with excellent characteristics, which performs sufficiently stable matching using one unit amplifier.

In order to achieve the above object, the microwave amplifier of the present invention uses a directional coupler to make one end of the input side of a hybrid circuit a signal input terminal, and connects a non-reflection termination to the other terminal of the input side of the hybrid circuit. A microwave amplifier is connected to one end of the output side of the hybrid circuit, and a passive circuit consisting of a matching circuit and a non-reflection termination having an input impedance equal to the input impedance of the microwave amplifier is connected to the other end of the output side of the hybrid circuit. The feature is that a circuit network is provided.

The present invention will be described in detail below with reference to examples.

The present invention is particularly useful for realizing matching circuits on the output side, where active three-terminal elements such as FETs and bipolar transistors used in microwave amplifiers as shown in Figure 1 normally have low input impedance, but relatively high output impedance. This is based on the fact that there is no problem and that a sufficiently satisfactory matching can be obtained even as a passive network by omitting the hybrid circuit 12 on the output side as shown in Fig. 2.In connection with this, one unit amplifier can be used. It is only possible to do so.

FIG. 3 is an explanatory diagram showing the structure of an embodiment of the present invention according to the above-mentioned principle.

In the figure, the input terminal 10 is connected to one of the two input terminals 11-1 of a hybrid circuit 11 similar to that in FIG. 11-4 is connected to a unit amplifier 21 to take out an output from an output terminal 20, and the other 11-3 is connected to a passive network 22 consisting of a matching circuit 23 and a non-reflection termination 24. The configuration of this passive circuit network 22 is that the unit amplifier 21
The reflection coefficient at the input side of the hybrid circuit 11, that is, one output terminal 11-4 of the hybrid circuit 11, and the reflection coefficient at the other output terminal 11-3 of the hybrid circuit 11 are set to have the same amplitude and the same phase, As a result, the input terminal 11-1 of the hybrid circuit 11 has equal amplitude and opposite phase, which improves the input impedance of the amplifier.

Hereinafter, the results of examining the characteristics of the present invention, which has improved characteristics using the unit amplifier shown in FIG. 1, will be explained.

Figure 4 shows the gain and input when changing the frequency of the 6GHz band unit amplifier using the circuit in Figure 1.
VSWR, indicates the output VSWR value. i.e. gain 13dB±0.2dB at frequency 5.7~6.3GHz, input VSWR4
Below, the output VSWR will be 1.4 or less.

FIGS. 5 and 6 show the results of improving the input impedance using this unit amplifier according to the configuration of the present invention shown in FIG. 3.

Figure 5 uses a 3dB hybrid circuit. In this case, the gain is 10.1± from 5.7 to 6.3GHz.
0.2dB, input VSWR of less than 1.2, and output VSWR of less than 1.5 were obtained.

Figure 6 uses a 2dB hybrid circuit. In this case, the gain is 11dB± from 5.7 to 6.3GHz.
0.2dB, input VSWR of less than 1.4, and output VSWR of less than 1.7 were obtained. Regarding the gain, in the examples shown in Figures 5 and 6, each is approximately approximately
The decrease is 3dB and 2dB.

However, the power consumption per unit gain is reduced to 65% in the case of FIG. 5 and 59% in the case of FIG. 6 compared to the conventional example. This effect is particularly noticeable in the case of high-gain amplifiers connected in multiple stages.

For example, if the power consumption of a unit amplifier is Pu, the conventional example uses 4 FETs and has a gain of 26 dB and the power consumption of 4 Pu, but according to the present invention using 3 dB hybrid, 3 FETs are used and the power consumption is 4 Pu. hand
The gain is 30dB, the power consumption is 3Pu, and when using a 2dB hybrid, it is 33dB using 3 FETs.
The gain is 3Pu, and the power consumption is 3Pu.

In the embodiment, an example using a branch type (or hybrid ring type) hybrid circuit is shown, but exactly the same effect can be obtained by using a distributed coupling type directional coupler.

As explained above, according to the present invention, by connecting a unit amplifier and a passive network to the two output terminals of an input hybrid circuit and performing matching to improve the input impedance, the unit amplifier This greatly contributes to reduction in number, downsizing, power consumption, and cost reduction.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the configuration of a conventional unit amplifier;
The figure is an explanatory diagram of the configuration of a conventional microwave amplification device, Figure 3 is an explanatory diagram of the configuration of an embodiment of the present invention, Figure 4 is a characteristic diagram of a conventional unit amplifier, and Figures 5 and 6 are diagrams of the configuration of an embodiment of the present invention. A characteristic diagram of the embodiment is shown, in which 10 is an input terminal, 11 is a hybrid circuit, 20 is an output terminal, 2
1 is a unit amplifier, 22 is a passive circuit network, 23 is a matching circuit, and 24 and 25 are non-reflection terminations.

Claims (1)

[Scope of utility model registration request] Using a directional coupler, one end of the input side of the hybrid circuit is used as a signal input terminal, a non-reflection termination is connected to the other terminal of the input side of the hybrid circuit, and a microwave amplifier is connected to one end of the output side of the hybrid circuit. A microwave amplification device characterized in that a passive circuit network having an input impedance equal to the input impedance of the microwave amplifier and consisting of a matching circuit and a non-reflection termination is provided at the other end of the output side of the hybrid circuit.