JPH01206709A - Micro-wave and millimeter wave amplifier - Google Patents

Abstract

PURPOSE:To automate the phase adjustment of an amplifier and to decrease a manual work by providing a variable phase shifter, which can be electrically controlled, in a branching circuit and automatically controlling the variable phase shifter so that the output of a detector can be maximum. CONSTITUTION:A micro-wave millimeter wave amplifier is composed of a branching circuit 1 of an input, variable phase shifters 2 and 2' and amplifiers 3 and 3' which are provided in the respective branching circuits, a synthesizing circuit 4 to synthesize the outputs of the amplifiers 3 and 3', a detector 5 to detect the output of the synthesizing circuit 4 and a control circuit 6 to control the phase shifters 2 and 2' by the output of the detector 5. Thus, the output to be synthesized in the synthesizing circuit 4 is detected by the detector 5 and this signal is passed through the control circuit 6 which controls the phases of the phase shifters 2 and 2'. Then, the respective phases of the phase shifters 2 and 2' are automatically adjusted electrically. A phase difference due to the frequency of a micro-wave millimeter wave band and the fluctuation of the phase due to the temperature change of an amplifier system are compensated.

Description

[Detailed Description of the Invention] [Summary] Regarding an amplifier used in the microwave band and millimeter wave band (hereinafter referred to as a microwave and millimeter wave amplifier) using a distributed constant circuit, branching and combining using a branching circuit and a combining circuit. In order to prevent a drop in synthesis efficiency due to phase differences in the high-gain amplifiers and obtain high output, the branch circuit is equipped with an electrically controllable variable phase shifter, and the detector added to the synthesis circuit is The variable phase shifter is configured to be automatically controlled so that the output is maximized through a control circuit.

[Industrial application field]

The present invention relates to a high gain amplifier used in terrestrial radio equipment that uses radio waves in the microwave band and millimeter wave band.

It is well known that distributed constant circuits are used in microwave and millimeter wave amplifiers, and multistage gallium arsenide (GaAs) FET amplifiers are used for branching and combining using branching circuits and combining circuits. When combining a large number of high gain amplifiers, it is necessary to match the phases of the individual amplifiers.

[Conventional technology]

FIG. 4 is a block diagram of a conventional microwave millimeter wave amplifier. In the figure, 1 is a branch circuit, 3 and 3 are amplifiers composed of multi-stage Ga-FETs, 4 is a combining circuit, and 1 is a block diagram of a conventional microwave millimeter wave amplifier.
2 and 13 are terminating resistors of 50Ω.

Conventional microwave and millimeter wave amplifiers are adjusted by connecting an output meter, etc. to the output side, branching the input signal from a measuring device, etc. connected to the input side into two with branch circuit 1, and amplifying it with amplifier 3.3. The outputs of the amplifiers 3.3 and 3 are combined in a synthesis circuit 4, and the phase adjustment of each amplifier composed of GaAs FETs is manually performed using a scrubber etc. on the board on which these amplifiers are mounted so that the combined output is maximized. Is going. In this case, terminating resistors 12 and 13 are provided in the branch circuit 1 and the combining circuit 4, respectively, in order to absorb power reflected to the input side or the output side due to impedance mismatching of these amplifiers.

[Problem to be solved by the invention]

However, when a large number of amplifiers made of GaAsFETs are synthesized, the synthesis efficiency decreases due to phase differences between the individual amplifiers, and gain and phase fluctuations due to temperature changes of individual amplifiers and temperature fluctuations of branch circuits and combining circuits occur. There is a quality problem in that the output value fluctuates greatly.

Furthermore, as mentioned above, phase adjustment is performed manually on the board by cut-and-try, which makes this adjustment work complicated.Furthermore, phase matching is also required when replacing unit amplifiers to be synthesized, which reduces the number of man-hours required for adjustment work. The disadvantage is that there is a large amount of

In view of these problems, it is an object of the present invention to provide a microwave and millimeter wave amplifier that can automate the phase adjustment of a high gain amplifier to eliminate manual work, can also cope with temperature fluctuations, and can provide high output. The purpose is

[Failure to solve the problem]

FIG. 1 is a block diagram of the principle of the microwave and millimeter wave amplifier of the present invention, in which after branching in a branch circuit 1, each amplifier 3.
A variable phase shifter of 2.2° is inserted on the input side of each 3°,
Furthermore, a detector 5 and a control circuit 6 for controlling the phase of the variable phase shifter 2.2' by the output of the detector 5 are provided on the output side of the combining circuit 4.

[Function] In the present invention, the output synthesized by the synthesis circuit 4 is detected by the detector 5, and this signal is used to control the phase of the variable phase shifter 2.2°.
The individual phases of the variable phase shifter 2.2'' shown in FIG. Compensates for fluctuations.

The above configuration eliminates the work that conventionally required manual phase adjustment, resulting in a significant cost reduction.

〔Example〕

FIG. 2 shows a block diagram of a microwave and millimeter wave amplifier according to an embodiment of the present invention.

Further, FIG. 3 shows a block diagram of a microwave and millimeter wave amplifier according to another embodiment of the present invention.

Furthermore, FIG. 5 shows the input/output power characteristics of each amplifier 3.3'' of the microwave and millimeter wave amplifier.

In FIGS. 2 and 3, the same parts as those shown in FIG. 4 described above are indicated by the same symbols.

FIG. 2 shows an example of using the microwave and millimeter wave amplifier of the present invention in a non-saturation region, in which a variable attenuator 9.9° and a detector 10 detecting the output of the amplifier 3.3° are used to adjust the gain of the amplifier.
．． 10” and automatic level control circuit (ALC) 11.1
1", so that the output of each amplifier 3.3" is constant.

Furthermore, isolators 7.7° and 8.8° are provided on the input and output sides of each amplifier to prevent reflections due to impedance mismatch.

When the present invention is used in a non-saturation region as shown in FIG. is used to control the variable phase shifter 2.2' through the control circuit 6 so that the combined output is maximized. Immediately, in this case,
First, the output level of each amplifier 3.3'' is matched, and then the phase is automatically adjusted.

Further, FIG. 3 is an example in which the microwave and millimeter wave amplifier of the present invention is used in the saturation region. Here, when used in the saturated region, 1-state or 4-phase PSK (Phase 5ift Ke
This is the case where the forceps component does not have much influence, such as the ying) method. In this case, unlike the case where the amplifier is used in a non-saturation region, the unbalance of the gain of the amplifier 3.3 is irrelevant, and only the change in phase is related to the synthesis efficiency.

Therefore, the variable attenuator 9.9' and the detector 10.10 in FIG.
゛ and ALC, 1, 1, 11 ゛ are unnecessary.

Since the phase control is the same as that explained in FIG. 2, it will be omitted.

In FIG. 5, the two-tree lines a and b indicate the input/output characteristics of the amplifier 3 and the amplifier 3, and Pinl and Pinl' (not shown) indicate the input power of the amplifier 3. Pout 2 and Pout 2' are amplifier 3.
It shows the output power of 3゛.

Moreover, PinA indicates the input power of branch circuit 1, and Pout
B indicates the output power of the combining circuit 5.

PinA has a gain of 3 db higher than Pinl (or Pine'). When two series of powers are combined in the same phase by the combining circuit 4, the input/output characteristics between the input power of the branch circuit 1 and the combined output power of the combining circuit 4 are ideal characteristics shown by the dotted line. When the phase is shifted, as shown by the dashed line, the gain and saturation power decrease compared to the characteristics shown by the dotted line.

The region shown in the figure where the change in input power versus output power is linear is called a non-saturated region, and the region where it is saturated is called a saturated region.

When using a microwave and millimeter wave amplifier in the saturation region, the ideal characteristics shown by the dotted line in Figure 5 can be obtained by performing automatic phase adjustment using the variable phase shifter 2.2 of the present invention. Therefore, synthesis efficiency is improved and maximum output is sought.

〔Effect of the invention〕

As explained above, according to the present invention, compared to conventional microwave and millimeter wave amplifiers, phase adjustment is automated and phase changes due to temperature fluctuations are also compensated for, resulting in shorter adjustment time and improved quality. Great effect can be obtained.

The present invention can also be used in multi-branch synthesis with two or more branches.

[Brief explanation of the drawing]

FIG. 1 is a principle block diagram of a microwave and millimeter wave amplifier according to the present invention, FIG. 2 is a block diagram of a microwave and millimeter wave amplifier according to an embodiment of the present invention, and FIG. 3 is a block diagram of a microwave and millimeter wave amplifier according to another embodiment of the present invention. Figure 4 is a block diagram of a conventional microwave and millimeter wave amplifier, and Figure 5 shows the input/output power characteristics of the amplifier.

Claims (1)

[Claims] An input branch circuit (1), an amplifier (3, 3') provided in each branch path of the branch circuit (1), and the output of each amplifier (3, 3') are combined. A microwave millimeter wave amplifier equipped with a combining circuit (4), comprising: a variable phase shifter (2, 2') in at least one branch path; a detector (5) for detecting the combined output; and the detector. A control circuit (6) is provided to control the variable phase shifter (2, 2') with the output of A microwave millimeter wave amplifier characterized in that the phase shifter (2, 2') is controlled.