JPH0281503A - Microwave amplifier circuit - Google Patents

Abstract

PURPOSE:To obtain stable performance by insulating each microwave amplifier FET after distributing signal power and an input waveguide in terms of DC, connecting the input waveguides with a connection waveguide having a resistor part on its way and applying a DC bias voltage to each microwave amplification FET gate via the connection guide. CONSTITUTION:The input waveguides 3a, 3b are connected by the connection waveguide 4, a resistor 5 is provided to the connection waveguide 4 so as to apply an input to both the microwave amplification elements 1a, 1b through the connection waveguide 4 and unstable operation such as oscillation due to interference between both the microwave amplification FETs 1a, 1b is eliminated. That is, the gates of the microwave amplification FETs 1a, 1b are connected by the connection waveguide 4, then a voltage is applied to the plural microwave amplification FETs 1a, 1b through the voltage application from one terminal. Moreover, since the resistor 6 is provided to the connection waveguide 4, the circuit instability due to high frequency coupling between the microwave amplification FETs 1a, 1b is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a microwave amplifier circuit, and particularly to an input circuit of a microwave amplifier.

[Conventional technology]

FIGS. 5 and 6 are connection diagrams showing conventional microwave amplification circuits.

In Fig. 5, la and lb are microwave amplification FETs.
, 2 is a distribution circuit that distributes the input signal, 3a and 3b are input waveguides that connect the distribution circuit 2 and microwave amplification FETs 1a and lb, and 6a and 6b are distribution circuits 2 and input waveguides 3a.
, DC cut capacitor that cuts directly between 3b, 7a
, 7b is a bias supply line that supplies voltage to the microwave amplification FETI, 8 is a bias current, and 9 is a distribution circuit 2.
Isolation resistors 14, 15, and 16 are the gate and source of microwave amplification FETs 1a and lb, respectively, added to the isolation boat.

and drain.

Next, the operation will be explained.

The signal wave transmitted from the input port side is distributed by the distribution circuit 2, passed through input waveguides 3a and 3b, and input to microwave amplification FETs 1a and 1b, where they are amplified and output. Here, the microwave amplification FETs 1a and lb are generally used with the source 15 grounded, and a negative voltage is applied to the gate 14 on the input side.In the conventional example, the negative power supply 13a,
3b through bias supply lines 7a, 7b and input waveguides 3a, 3b, respectively, to the microwave amplification FET 1.
A voltage is applied to a and lb. In addition, the capacitor 6a,
6b is the input boat, distribution circuit 2 and microwave amplification F
Microwave amplification FET1a is used to cut DC from ET1a and lb.

This prevents oscillations caused by mutual interference between lbs. Further, 9 is a resistor for absorbing signal leakage to the isolation hoard when the distribution circuit 2 is constituted by a four-terminal circuit such as an interdigitated coupler or a branch line coupler.

In FIG. 6, the same reference numerals as in FIG.
b is a resistor provided in the connection waveguide section, and 13 is a jumper wire connecting the connection waveguide 4 and the bias supply line 7.

In FIG. 6, voltage is applied to the gates 14 of the microwave amplification FETs 1a and lb from the bias supply line 7 to the connection 'If.
A jumper 13 is connected near the center of the t-wave director 4, and resistors 5a and 5b are connected from there.

[Problem to be solved by the invention]

A conventional microwave amplification circuit is configured as shown in FIGS. 5 and 6 above. In the circuit shown in FIG. 5, voltage must be supplied from both sides of each amplification element, and the circuit configuration is The disadvantage was that it was complicated. Furthermore, the circuit shown in FIG. 6 has the disadvantage that the jumper wire 13 crosses the input waveguide 3b through which the signal passes, and therefore the jumper wire affects the characteristics of the circuit.

This invention was made to solve the above-mentioned problems, and it is an object of the present invention to provide a microwave amplifier circuit that has a simple voltage supply and can provide stable performance.

[Means to solve the problem]

The microwave amplification circuit according to the present invention connects input waveguides with a connection waveguide, and provides a resistor in the connection waveguide so that input can be applied to both microwave amplification elements through the connection waveguide, and both FE for microwave amplification
This is intended to eliminate unstable operation such as oscillation due to interference between Ts.

[Effect]

In the microwave amplification circuit of the present invention, the gates of the microwave amplification elements are connected by a contact waveguide, so that voltage can be supplied to a plurality of microwave amplification elements by applying voltage from one end. Moreover, since the connecting waveguide is provided with a resistor, instability of the circuit due to high frequency coupling between the microwave amplifying elements can be prevented.

〔Example〕

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

FIG. 1 is a block diagram showing a microwave amplification circuit according to a first embodiment of the present invention. In the figure, la and lb are microwave amplification FETs, 2 is a distribution circuit for distributing input signals, and 3a and 3b are is distribution circuit 2 and microwave amplification FE
Input waveguides connecting T1a and lb, 6a and 6b are DCs that cut direct waves between the distribution circuit 2 and input waveguides 3a and 3b.
Cut capacitor, 7 is microwave amplification FET1a,
A bias supply line for supplying voltage to 1b, 8 a bias power supply, 9 an isolation resistor added to the isolation hoard of the distribution circuit 2, 14 a gate, 15 a source, and 16 a drain.

Next, the operation will be explained.

The signal wave transmitted from the input side port is distributed by the distribution circuit 2 as in the case of the conventional example, and passes through the input waveguide 3 of the DC cut capacitors 6a and 6b to the microwave amplification FE.
It is input to T1a and lb and is amplified and output. Microwave amplification FET1 a.

The negative voltage applied to each gate 14 of 1b is passed from a negative power supply 8 through a bias supply line 7 to a microwave amplification FET.
1b through the input waveguide 3b, and to the microwave amplification FET 1a through the connection waveguide 4 and input waveguide 3a. Therefore, FE71a for microwave amplification.

The voltage applied to 1b differs by the voltage change due to the current flowing through the resistor 5 provided in the connection waveguide 4. However, the FET 1a is usually used for microwave amplification.

Since the gate current value of 1b is very small, the characteristic difference between both microwave amplification FETs 1a and 1b due to this voltage change is due to the difference in characteristics between the microwave amplification FETs 1a and 1b.

This is smaller than the inherent difference between 1b and 1b. In addition, in order to prevent unstable characteristics such as oscillation caused by mutual interference between the micro width FE71a and lb, a DC cut capacitor 6 is used as an interference countermeasure through the distribution circuit 2 to prevent low frequency oscillation. To prevent interference through the connecting waveguide 4, a resistor 5 is provided to attenuate the leakage signal power, and the resistance value of the resistor 5 itself is set higher than the impedance of the MIC waveguide. The amount of leakage itself is also reduced.

Although the amount of signal leakage is suppressed by increasing the value of the resistor 5 provided in the connecting waveguide 4, the actual distance between the input waveguides 3a and 3b is smaller than the wavelength (λg). If it cannot be ignored, the phase shift will have an effect, and the resistance 5
Even if the resistance value of
Since the impedance taking this into account is not necessarily high, the amount of signal leakage to the connection waveguide 4 may be large.

FIG. 2 is a block diagram showing the configuration of a microwave amplification circuit according to a second embodiment of the present invention to eliminate the above-mentioned influence. RF between the /4 wavelength (λg/4) position and the ground conductor>
A-) capacitor 10a and LOb are connected. As a result, the connecting portion of the RF shorting capacitors 10a and 10b becomes a short end with respect to the signal wave, and the impedance seen from the input waveguides 3a and 3b separated by λg/4 becomes high. In this case, the resistor 5 is provided between the RF short capacitor connection parts 10a and 10b.

Further, FIG. 3 is a block diagram showing the configuration of a microwave amplification circuit according to a third embodiment of the present invention, in which a Y-shaped bone arrangement device 11 is adopted as the distribution circuit 2. In FIG.

In this case, an isolation resistor 12 is placed between both distribution ports.
is provided, so this can be directly connected to the input waveguides 3a, 3.
It can be used in place of the connecting waveguide 4 between b.

In addition, both microwave amplification F
In order to prevent interference between ETIs, the DC cut capacitor 6 also serves to prevent low frequency oscillations, similar to the previous embodiment.

In the first to third embodiments, the distribution circuit is described as a two-way distribution circuit, but the same configuration can of course be achieved by using the multi-output divider 17 shown in FIG. 4.

As described above, according to the present invention, since the gates of the microwave amplification elements are connected by the connection waveguide,
Voltage can now be supplied to multiple microwave amplification elements by applying voltage from one end, and since a resistor is provided in this connection waveguide, there is no risk of circuit damage due to high frequency coupling between the microwave amplification elements. Qualitative behavior can be prevented.

Note that the present invention is applicable to microwave amplification FEs such as HEMT devices.
It can also be applied to microwave amplification elements used with the same bias voltage and current as TI.

〔Effect of the invention〕

As described above, according to the present invention, each microwave amplification FET after signal power distribution and the input waveguide are insulated in terms of direct current, and the connecting conductor having a resistive part in the middle is connected between the input waveguides. By using a method in which a direct current bias voltage is applied to each microwave amplification FET gate through the connection waveguide, a microwave amplification circuit with a simple circuit configuration and stable high frequency characteristics can be achieved. can get.

[Brief explanation of the drawing]

FIG. 1 is a connection diagram showing a microwave amplification circuit according to a first embodiment of the present invention, FIG. 2 is a connection diagram showing a microwave amplification circuit according to a second embodiment of the invention, and FIG. 3 is a connection diagram showing a microwave amplification circuit according to a second embodiment of the present invention. 4 is a connection diagram showing a microwave amplification circuit according to a third embodiment of the present invention, FIG. 4 is a connection diagram of a microwave amplification circuit showing an application example of the present invention, and FIGS. 5 and 6 are a conventional microwave amplification circuit. FIG. In the figure, 1 is a microwave amplification FET, 2 is a distribution circuit, 3 is an input waveguide, 4 is a connection waveguide, 5 is a resistor, 6 is a DC cut capacitor, 7 is a bias supply line, 8 is a bias power supply, 9 is isolation resistor, 10 is RF
Short-circuit capacitor, 11 is a Y-shaped boner, 12 is an isolation resistor, 13 is a jumper wire, 14 is a gate,
15 is a source, and 16 is a drain. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) a plurality of microwave amplification elements and a distribution circuit that distributes microwave input to each of the microwave amplification elements;
A microwave amplification circuit comprising an input waveguide connecting each output of the distribution circuit and each of the microwave amplification elements, the microwave amplification circuit having a resistor part provided between each of the input waveguides in the middle thereof. A connecting waveguide, and a DC voltage applying means for applying a DC voltage to one of the input waveguides, and applying a DC voltage to the input side electrode of each of the microwave amplification elements via the connecting waveguide. A microwave amplification circuit characterized by: