JPH0828624B2 - High efficiency semiconductor amplifier - Google Patents

Description

The present invention relates to a high-efficiency semiconductor amplifier, and more particularly to a quasi-microwave / microwave band high-efficiency amplifier used in satellite communication, terrestrial microwave communication, and the like. .

[Conventional technology]

Fig. 3 shows, for example, T. Nojima, S. Nishiki, "High Efficiency Microwave Harmonic Reaction Amplifier", IEEE.MTT-S digest ("High EFFICIENCY Microwave Harmonic Reactio").
n Amplifier "IEEE.MTT-S Digest) 1988pp1007 to 1010 is a configuration diagram of a conventional high efficiency semiconductor amplifier. In the figure, 1 is an input terminal of the high efficiency semiconductor amplifier, 2 is its output terminal, and 3 is A power divider that divides the microwave signal received at the input terminal 1 into two, 5 and 6 are first and second FETs that amplify the respective distribution outputs, and input to the input side of each of these FETs 5 and 6. A matching circuit (not shown) and an output matching circuit (not shown) are provided on the output side, and 7a and 7b are fundamental wave bandpass filters connected to the subsequent stages of the FETs 5 and 6, respectively. It is a power combiner that combines the outputs of both filters 7a and 7b.

Reference numerals 8a and 8b are second-harmonic bandpass filters connected to the subsequent stages of the first and second FETs 5 and 6, respectively, and 9 is a phase shifter connected between the outputs of the filters 8a and 8b.

 Next, the operation will be described.

The microwave input from the input terminal 1 is divided into two by the power divider 3 and supplied to the first FET 5 and the second FET 6. Here, the operating points of the first FET 5 and the second FET 6 are set to class B or class AB in order to improve efficiency.

At this time, the fundamental wave components in the outputs of the first FET 5 and the second FET 6 are combined by the power combiner 4 via the fundamental wave bandpass filters 7a and 7b that pass only the fundamental wave and block the second harmonic. And output to the output terminal 2.

The second harmonic component in the output of the first FET 5 is a second harmonic band pass filter that passes only the second harmonic and blocks the fundamental wave.
It is injected into the second FET 6 through 8a, the phase shifter 9 and the filter 8b. Similarly, the second harmonic component in the output of the second FET 6 is also injected into the first FET 5 via the filter 8b, the phase shifter 9 and the filter 8a. Optimizing the second harmonic injection phase by adjusting the phase shifter 9 improves the efficiency of the amplifier.

[Problems to be Solved by the Invention]

Since the conventional high-efficiency semiconductor amplifier is constructed as described above, there is a problem that four bandpass filters are required and the number of parts is increased. In addition, there is a 2nd harmonic injection path that injects the 2nd harmonic output of one FET into the other FET.
Since it consists of two bandpass filters and phase shifters,
There has been a problem that the phase rotation of the second harmonic due to the second harmonic injection path is large and the band in which the amplification efficiency is improved is narrowed.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain a high-efficiency semiconductor amplifier capable of reducing the number of components and downsizing, and widening the band in which the amplification efficiency is improved. To aim.

[Means for solving the problem]

The high-efficiency semiconductor amplifier according to the present invention has a circuit configuration in which an input microwave signal is divided into two and each divided output is amplified by the first and second amplifying elements, and power combining means for combining the amplified outputs is added. The amplifier elements are connected to each other via first and second second-harmonic phase adjusting lines that adjust the phase of only the second harmonic, and a low-pass filter is provided on the output side of the power combining means. The second-harmonic injection path for injecting the second-harmonic component of the output of the second amplification element into the other amplification element is composed of the output matching circuit of each amplification element, the second-harmonic phase adjustment line, and the power combining means. It is composed.

[Action]

In the present invention, the low-pass filter is provided on the output side of the power combiner, and the second-harmonic injection path for injecting the second-harmonic component of the output of one amplification element into the other amplification element is provided.
Since the output matching circuit of each amplification element, the second harmonic phase adjusting line that adjusts the phase of only the second harmonic, and the power synthesizing means are used, two low pass filters as the fundamental wave band pass filter, which are conventionally required. The number of filters can be reduced to one, and the second-harmonic bandpass filter, which was conventionally required to be two, can be eliminated, whereby the number of parts can be reduced and the device can be downsized.

Further, since the second-harmonic bandpass filter is not used in the second-harmonic injection path, the phase rotation of the second-harmonic wave can be reduced, and thus the band in which the amplification efficiency is improved can be widened.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a high efficiency semiconductor amplifier according to an embodiment of the present invention. In the figure, the same symbols as those in FIG. 3 indicate the same or corresponding parts. 10a and 10b are first and second
Is an input matching circuit provided on the input side of the FET (amplifying element), and 11a and 11b are output matching circuits connected to the output sides of the FETs 5 and 6, respectively. Here, the input matching circuit 10a, 10
In b, impedance matching is performed on the fundamental wave, and the output matching circuit 11 performs impedance matching on the fundamental wave and the second harmonic wave.

Reference numerals 12a and 12b denote second-harmonic phase adjustment lines that form transmission lines between the output matching circuits 11a and 11b and the power combiner (power combiner) 4, respectively. The band pass filter) 7 is provided between the output of the power combiner 4 and the output terminal 2.

 Next, the operation will be described.

The microwave input from the input terminal 1 is divided into two by the power divider 3 and supplied to the first FET 5 and the second FET 6. Here, the operating points of the first FET 5 and the second FET 6 are set to class B or class AB in order to improve efficiency as in the conventional case.

At this time, the fundamental wave components of the outputs of the first FET 5 and the second FET 6 are combined by the power combiner 4 through the output matching circuits 11a and 11b and the second harmonic wave phase adjusting lines 12a and 12b, and the fundamental wave component is obtained. It passes through the bandpass filter 7 and is output to the output terminal 2.
In this case, when there is no variation in characteristics between the first FET 5 and the second FET 6 and the lengths of the two second harmonic wave phase adjusting lines 12a and 12b are equal, the first FET 5 and the second FET 6 are Only the common mode exists in the fundamental wave amplified by the FET 6 of, and all the fundamental waves are combined by the power combiner 4 without being injected into the other FET and pass through the fundamental wave bandpass filter 7. It is output to the output terminal 2. In other words, the line for adjusting the phase of the second harmonic
If the lengths of 12a and 12b are equal, even if the length of the second harmonic phase adjusting line is adjusted, the fundamental wave impedance seen from the first FET 5 to the load side does not change.

The second harmonic component in the output of the first FET5 is the output matching circuit.
11a, 11b, 2nd harmonic phase adjusting lines 12a, 12b, power combiner 4
Is injected into the second FET 6 via the second harmonic injection path constituted by. The second harmonic component in the output of the second FET 6 is similarly injected into the first FET 5.

Since the fundamental wave bandpass filter 7 blocks the second harmonic wave, all the second harmonic waves generated by operating the first FET 5 in the class B or class AB are injected into the second FET 6. Similarly, all the second harmonics generated by operating the second FET 6 in the class B or class AB are injected into the first FET 5.

The second harmonic impedance looking into the load side from the first FET 5 is equivalently the second harmonic generated by operating the first FET 5 in class B or class AB (second harmonic propagating in the load direction), It can be defined as a ratio with the second harmonic (second harmonic propagating in the load direction) generated by operating the second FET 6 in class B or class AB.

Therefore, the second harmonic impedance looking into the load side from the first FET 5 is obtained by adjusting the length of the second harmonic phase adjusting lines 12a and 12b and changing the phase of the second harmonic injected into the FET5. , Can be adjusted. Look at the load side from the second FET6 2
The same applies to the harmonic impedance.

As described above, in this embodiment, the fundamental wave bandpass filter 7 is provided on the output side of the power combiner 4, and the second harmonic wave component for injecting the second harmonic wave component of the output of one FET 5 or 6 into the other FET 6 or 5 is injected. Since the path is composed of the output matching circuits 11a and 11b, the second harmonic wave phase adjusting lines 12a and 12b, and the power combiner 4, two fundamental wave bandpass filters 7 which are conventionally required are provided.
Only one is required. Also, the second-harmonic bandpass filter, which was conventionally required for two, is no longer necessary, and the number of parts can be reduced and the size can be reduced.

Further, since the second-harmonic bandpass filter is not used in the second-harmonic injection path, the phase rotation of the second harmonic can be suppressed to be small, and the band in which the efficiency of the amplifier is improved can be widened.

In the above embodiment, the case where the power distributor and the power combiner are used as the power distributor and the power combiner, respectively, has been described. However, the T branch or the coupler may be used for one or both of them. .

FIG. 2 shows a high efficiency semiconductor amplifier according to another embodiment of the present invention. In this embodiment, as shown in FIG. 2, in the embodiment of FIG. 1, the power divider 3 is the input side T branch 13, the power combiner 4 is the output side T branch 14, and the fundamental band pass filter 7 is provided. It is replaced by the low-pass filter 15. In this case, since the T branch is used for the power distribution means and the power combining means, the configuration of the device can be further simplified in addition to the effects of the above-described embodiment.

〔The invention's effect〕

As described above, according to the high-efficiency semiconductor amplifier according to the present invention, in addition to the circuit configuration in which the input microwave signal is divided into two and each divided output is amplified by the first and second amplifying elements,
The power combining means for combining the amplified outputs is connected to each of the amplifying elements via the first and second second harmonic phase adjusting lines for phase adjusting only the second harmonic, and the output side of the power combining means is connected. A low-pass filter is installed in the
Since the second harmonic injection path for injecting the second harmonic component is composed of the output matching circuit of each amplification element, the second harmonic phase adjusting line for adjusting the phase of only the second harmonic, and the power combining means, the number of parts is reduced. Can be reduced to reduce the size of the device, and the phase rotation of the second harmonic can be reduced to widen the band in which the efficiency of the amplifier is improved.

[Brief description of drawings]

FIG. 1 is a block diagram of a high efficiency semiconductor amplifier according to an embodiment of the present invention, FIG. 2 is a block diagram of a high efficiency semiconductor amplifier according to another embodiment of the present invention, and FIG. 3 is a conventional high efficiency semiconductor amplifier. It is a block diagram. In the figure, 1 is an input terminal, 2 is an output terminal, 3 is a power distributor (power distributing means), 4 is a power combiner (power combining means),
Reference numerals 5 and 6 are first and second FETs (amplifying elements), 7 is a fundamental wave band pass filter (low pass filter), 12a and 12b are second harmonic phase adjusting lines, and 13 is an input side T branch (power). Distribution means), 14
Is a T-branch on the output side (power combining means), and 15 is a low-pass filter. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A high-efficiency semiconductor amplifier that receives a microwave signal at an input terminal, amplifies the microwave signal, and outputs the amplified output signal to an output terminal. A power distribution unit that is connected to the input terminal and divides and outputs the microwave signal in two. Through the first and second amplification elements for amplifying the respective distributed outputs, and the first and second second-harmonic phase adjustment lines for adjusting the phase of only the second harmonic to the output of each amplification element. High efficiency characterized in that it comprises: a power combining means for connecting the outputs of the respective amplifying elements, and a low-pass filter connected between the output of the power combining means and the output terminal. Semiconductor amplifier.