JPS62207006A - Microwave oscillator - Google Patents

Abstract

PURPOSE:To apply MMIC of a microwave oscillator whose oscillating frequency is voltage-controlled together with a varactor diode of a resonance circuit or a feedback capacitance circuit by acting the 2nd FET like the resonaance circuit or feedback capacitance circuit of the 1st FET. CONSTITUTION:A negative resistance circuit 11 consists of a FET 12 and a peripheral circuit and a resonance circuit 13 is connected to a gate terminal 14 of the FET 12 together with the amplification function. An inductor 17 is connected between a gate terminal 16 of a FET 15 and a gate terminal 14 of the FET 12 and the negative resistance circuit 11 is oscillated at a frequency close to the resonance frequency of a series resonance circuit comprising an inductance Lg of the strip line 17 and a gate-source capacitance Cg of the FET 15, an output matching circuit 18 of an amplifier 13' consists of a strip line and the oscillated power is amplified by the amplifier 13' and outputted from an output terminal 19. Thus, microwave monolithic integrated circuit (MMIC) is facilitated and the negative resistance circuit 11 and the output terminal 19 of the microwave oscillator are isolated by the FET 15 to form the immunity against the load fluctuation.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention is applicable to an oscillator resonant circuit or a feedback capacitance circuit.
The present invention relates to a microwave oscillator using T.

2. Description of the Related Art As a method of varying the oscillation frequency of a negative resistance type oscillator or a feedback type oscillator by voltage control, it is common to use a variable capacitance diode in the resonant circuit or feedback capacitance circuit of these oscillators. For example, a circuit configuration as shown in FIG. 7 has been used as a microwave oscillator whose oscillation frequency can be controlled by voltage using a semiconductor oscillation element and a variable capacitance diode.

In FIG. 7, reference numeral 1 denotes a negative resistance circuit, which includes an FET 2, which is a semiconductor oscillation element, and its peripheral circuits (not shown).

3 is a resonant circuit, which includes an inductor 4 and a variable capacitance diode 5.
The resonant circuit 3 is connected to the negative resistance circuit 1. By controlling the voltage applied to the variable capacitance diode 5, the resonant frequency of the resonant circuit 3 is changed, thereby controlling the oscillation frequency of the microwave oscillator.

Problems to be Solved by the Invention In the microwave oscillator using the conventional variable capacitance diode as described above, even if the negative resistance circuit 1 can be made into a microwave monolithic integrated circuit (hereinafter abbreviated as MMIC), the variable capacitance diode It was difficult to convert the resonant circuit 3 including the resonant circuit 6 into an MMIC.

Therefore, there was a problem in that it was difficult to incorporate the entire microwave oscillator 6 into an MMIC.

The present invention has been made in view of the above points, and an object of the present invention is to provide an MMIC for a microwave oscillator whose oscillation frequency can be controlled by voltage, including a variable capacitance element of a resonant circuit or a feedback capacitance circuit.

Means for Solving the Problems The present invention uses an FET as a variable capacitance element in a resonant circuit or a feedback capacitance circuit of a microwave oscillator, and the gate-source capacitance or gate-drain capacitance of the FET is This takes advantage of the fact that it can be varied by changing the voltage between the source or the voltage between the gate and drain.

Operation According to the present invention, the variable capacitance elements of the resonant circuit and the feedback capacitance circuit can also be made into MMICs, so that the entire microwave oscillator can be made into MMICs.

Embodiment FIG. 1 shows a first embodiment of the microwave oscillator of the present invention. In FIG. 1, 11 is a negative resistance circuit consisting of an FET 12 and its peripheral circuits (not shown). 13 is a resonant circuit that also has an amplification function, and is connected to the gate terminal 1 of FET 12.
Connected to 4.

16 is a FET, and the gate terminal 16 of FET16 and FET1
An inductor 17 is connected between the gate terminals 14 of the strip line 17, and the inductance L of the strip line 17 is
The negative resistance circuit 11 oscillates at a frequency close to the resonant frequency of the series resonant circuit formed by the gate-source capacitance C9 of the FET 15. Reference numeral 18 denotes an output matching circuit of the amplifier 1, which is composed of an IJ tube line, and the oscillation power is amplified by the amplifier 13' and outputted from the output terminal 19.

20. 21 is a DC blocking capacitor, 22 is a high frequency short circuit capacitor, 23 is a gate bias resistance of FET 15,
24 is a gate bias terminal, and 26 is a drain bias terminal of the FET 15.

In the embodiment shown in FIG. 1, the negative resistance circuit 11 and the resonant circuit 13 are composed of FETs, so that the entire microwave oscillator can be easily integrated into an MMIC. Also,
Since the negative resistance circuit 11 and the output terminal 19 of the microwave oscillator are isolated by the FET 15,
Microwave oscillators are resistant to load fluctuations.

FIG. 2 shows a second embodiment of the microwave oscillator of the present invention, and the same parts as in FIG. 1 are given the same numbers and will be described.

In FIG. 2, 11' is a negative resistance circuit consisting of an FET 12 and its peripheral circuits (not shown). 26 is a resonant circuit that also has an amplification function, and is connected to the gate terminal 1 of FET 12.
Connected to 4. 15 is an FET, and a strip line 17 is connected between the gate terminal 16 of the FET 1s and the gate terminal 14 of the FET 12, and the gate terminal 14 and the gate terminal 16 are connected in a direct current manner. Negative resistance circuit 11'
are the inductances Lg and F of the strip line 17
It oscillates at a frequency close to the resonant frequency (=%π product) of the resonant circuit formed by the gate-source capacitance Cg of the ET15. Reference numeral 18 denotes an output matching circuit of the amplifier 13', which is composed of a strip line, and the oscillation power is amplified by the amplifier 13' and outputted from the output terminal 19. 21 is a DC blocking capacitor, 22 is a high frequency short circuit capacitor, 23 is FET1
2 and the gate bias resistance of the FET 15, 24 the gate bone bias terminal, and 25 the drain bias terminal of the FET 1s.

In the embodiment shown in FIG. 2, in addition to the effect shown in FIG. 1, the gate bias voltage applied to the gate bias terminal 24 acts on both FET1es and FET12, so Not only the source-to-source capacitance Cg, but also the F E T 12 node-to-source capacitance C
Since g' also changes with respect to the gate bias voltage, it has the effect of widening the variable range of the oscillation frequency of the microwave oscillator.

FIG. 3 shows a third embodiment of the microwave oscillator of the present invention, and the same parts as in FIG. 1 are given the same numbers and will be described.

In FIG. 3, 31 is a negative resistance circuit, 13 is a resonant circuit, and the circuit configuration other than the negative resistance circuit 31 is completely the same as in FIG. 1. The negative resistance circuit 31 has a drain-grounded circuit configuration of the FET 12. The source terminal 32 of the FET 12 is connected to a choke line 33 whose terminal end is grounded and a source terminal 32.
A bias resistor 34 is connected in series. FET12
The gate terminal 14 of is grounded via a high resistance 36. Connected to the drain terminal 36 of the FET 12 is a drain inductor 38 whose terminal end is grounded at high frequency with a high frequency shorted capacitor 37 . 39 is the output terminal of the microwave oscillator, and 40 is the drain bias terminal of the FET 12.

In the embodiment shown in FIG. 3, the negative resistance circuit 31 and the resonant circuit 13 are composed of FETs, so that the entire microwave oscillator can be easily integrated into an MMIC. Also,
There are two output terminals (output terminals 19 and 39), and these output terminals 19 and 39 are isolated, so there is no need for a divider to divide the oscillation output into two, and at the same time, the mutual influence of loads is reduced. can be removed.

FIG. 4 shows a fourth embodiment of the microwave oscillator of the present invention, and the same parts as in FIG. 2 are given the same numbers and will be described.

In FIG. 4, 41 is a negative resistance circuit, 26 is a resonant circuit, and the circuit configuration other than the negative resistance circuit 41 is completely the same as in FIG. 2. The negative resistance circuit 41 has a drain-grounded circuit configuration of the FET 12. A choke line 43 whose terminal end is grounded is connected to the source terminal 42 of the FET 12. Connected to the drain terminal 46 of the FET 12 is a drain inductor 48 whose terminal end is grounded at high frequency with a high frequency shorted capacitor 47 .

49 is the output terminal of the microwave oscillator, 6o is FET12
This is the drain bias terminal of

In the embodiment shown in FIG. 4, the negative resistance circuit 41 and the resonant circuit 26 are composed of FETs, so that the entire microwave oscillator can be easily implemented as an MMIC. Also,
Since there are two output terminals (output terminals 19.49) and these output terminals 19.49 are isolated, there is no need for a divider to divide the oscillation output into two, and at the same time, the mutual influence of loads is reduced. can be removed. Furthermore, since the gate bias voltage applied to the gate bias terminal 24 acts on both FET15 and FET12, not only the gate-to-source capacitance Cg of FET1s but also the gate-source capacitance 09' of FET12 is
Since it changes with the bias voltage, it has the effect of widening the variable range of the oscillation frequency of the microwave oscillator.

FIG. 6 shows a sixth embodiment of the microwave oscillator of the present invention, and the same parts as in FIG. 3 are given the same numbers and will be described.

In FIG. 6, a negative resistance circuit 31 has a drain-grounded circuit configuration of an FET 12. A choke line 33 whose terminal end is grounded and a source bias resistor 34 are connected in series to the source terminal 32 of the FET 12. There is. F
The gate terminal 14 of E T 12 is connected to ground via a high resistance 36 . Connected to the drain terminal 36 of the FET 12 is a drain inductor 38 whose terminal end is grounded at high frequency with a high frequency shorted capacitor 37 .

39 is the output terminal of the microwave oscillator, 40 is FET12
This is the drain bias terminal of A resonant circuit 53 is connected to the gate terminal 14 of the FET 12, and the resonant circuit 53 is connected to the FET 16 with the drain terminal 51 open.
It consists of a strip line 17 connected between the gate terminal 16 of FET 15 and the gate terminal 14 of FET 12. 20 is a DC blocking capacitor, 23 is FET
1' 5 is a gate bias resistor, 24 is a gate bias terminal. The negative resistance circuit 31 oscillates at a frequency close to the resonant frequency of the series resonant circuit formed by the inductance Lg of the strip line 17 and the source-to-source capacitance C9 of the FET 16, and its oscillation output is supplied from the output terminal 39. be done.

In the embodiment shown in FIG. 6, the negative resistance circuit 31 and the resonant circuit 63 are constituted by FETs, so that the entire microwave oscillator can be easily implemented as an MMIC. Also F
Since the drain terminal 51 of the ET15 is open and no drain bias voltage is applied to the FET15, looking from the gate terminal 16 to the FET1s side, the impedance Z
The resistance value Rg of g (=R9+jxg) becomes smaller, and the no-load Q value of the resonant circuit 53 becomes larger. Moreover, the resistance value R
9 does not depend on the depth of the gate bias voltage of the FET 16, so the oscillation state of the microwave oscillator can be stabilized, and since the gate bias voltage can be changed greatly, it has the effect of widening the variable range of the oscillation frequency.

FIG. 6 shows a sixth embodiment of the microwave oscillator of the present invention, and the same parts as in FIG. 4 are given the same numbers and will be described.

In FIG. 6, 41 is a negative resistance circuit, 63 is a resonant circuit, and the circuit configuration other than the resonant circuit 63 is completely the same as that in FIG. 4. The negative resistance circuit 41 has a drain-grounded type circuit configuration of the FET 12. A choke line 43 whose terminal end is grounded is connected to the source terminal 42 of the FET 12. Connected to the drain terminal 46 of the FET 12 are drain inductors 4 and 8 whose ends are grounded at high frequency with a high frequency short-circuit capacitor 47 .

49 is the output terminal of the microwave oscillator, 6o is FET12
This is the drain bias terminal of A resonance circuit 63 is connected to the gate terminal 14 of the FET 12,
The resonant circuit 63 connects the FET 1 whose drain terminal 61 is grounded.
5 and a strip line 17 connected between the gate terminal 16 of FET1ts and the gate terminal 14 of FET12. 23 is a gate bias resistor, and 24 is a gate bias terminal. The sum C of the inductance Lg of the strip line 17, the gate-source capacitance Cg, and the gate-drain capacitance Cgd of the FET 16
The negative resistance circuit 41 oscillates at a frequency close to the series resonance frequency formed by g''=Cg+C9d, and its oscillation output is supplied to the load from the output terminal 49.

In the embodiment shown in FIG. 6, the negative resistance circuit 41 and the resonant circuit 63 are composed of FETs, so that the entire microwave oscillator can be easily integrated into an MMIC. Also FE
Since the drain terminal 61 of T15 is grounded and no drain bias voltage is applied to the FET1s, the tine beater 7 is connected to the FET16 side from the gate terminal 16.
, the resistance value R9 of (=FLg+1X9) becomes smaller,
The no-load Q value of the resonant circuit 63 increases. Moreover, since the resistance value R does not depend on the depth of the gate bias voltage of the FET 16, the oscillation state of the microwave oscillator can be stabilized, and since the gate bias voltage can be changed greatly, the oscillation frequency can be varied over a wide range. have

Furthermore, since the drain terminal 61 of FET 1s is grounded, the capacitance C when looking at the FET 1s side from the gate terminal 16
" can be made larger by C9d than the capacitance C when the drain terminal 61 is open, so the inductance L9 of the strip line 17 to obtain the same resonance frequency can be
Since it is possible to reduce the size of the strip line 17, the size of the resonant circuit 630 can be reduced. Also, since the gate bias voltage applied to the gate bias terminal 24 acts on both FET 16 and FET 12, the FE
Since not only the capacitance 09' due to T16 but also the capacitance C91 due to FET 12 changes with respect to the gate bias voltage, it has the effect of widening the variable range of the oscillation frequency of the microwave oscillator.

In the embodiments described above, the negative resistance type microwave oscillator has a configuration in which a resonant circuit is connected to a negative resistance circuit, but the configuration does not necessarily have to be as described in the embodiments. For example, it goes without saying that a feedback type microwave oscillator composed of a feedback capacitor circuit using an FET and an FET amplifier may be used. Furthermore, in the third to sixth embodiments, the negative resistance circuit is a grounded FET drain type.
It goes without saying that it does not necessarily have to be a common drain type, and may be a common source type or a common gate type as long as it functions as a negative resistance circuit. Effects of the Invention As described above, in the embodiments of the present invention, a resonant circuit or a feedback circuit can be used. Since the gate-source capacitance or gate-drain capacitance of the FET is used as the variable capacitance element used in the capacitance circuit, the entire microwave oscillator can be made into an MMIC together with the negative resistance circuit and feedback amplifier constituted by the FET.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a microwave oscillator according to a first embodiment of the present invention, FIG. 2 is a block diagram of a microwave oscillator according to a second embodiment of the present invention, and FIG. 4, 6, and 6 are the third and fourth figures of the present invention, respectively.
．． Fifth. A configuration diagram of a microwave oscillator in the sixth embodiment, and FIG. 7 is a configuration diagram of a conventional microwave oscillator. 11.11', 31.41... Negative resistance circuit,
12゜16...FET, 13.26.53.6
3...Resonant circuit, 13'...Amplifier,
14.16...Gate terminal, 17...
Strip line, 1B... Output matching circuit, 19
, 39.49...Output terminal, 20°21...
...DC blocking capacitor, 22, 37.47...
...High frequency short-circuit capacitor, 23.35...Gate bias resistor, 24...Gate bias terminal, 25,40.60...Drain bias terminal, 32. 42... Source terminal, 33.
43...Tetag line, 34...Source bias resistance, 36.46,5i1. 61...
...Drain terminal, 38°48...Drain inductor. Name of agent: Patent attorney Toshio Nakao and 1 other person (0)
C)

Claims (1)

[Claims] (1) The first FET is used as an amplification element, the second FET is used as a variable capacitance element, and the second FET is operated as a resonant circuit or a feedback capacitance circuit for the first FET. Microwave oscillator with special features. (2) The second FET is not only used as a variable capacitance element, but also
The microwave oscillator according to claim 1, wherein the microwave oscillator is also operated as an amplification element. (3) A negative resistance circuit is formed by the first FET, and a resonant circuit formed by the second FET is connected to this negative resistance circuit. Microwave oscillator. (4) Open the drain terminal of the second FET, and
2. The microwave oscillator according to claim 1, wherein a gate-source capacitance of an ET is used as a variable capacitance element. (6) The source terminal and the drain terminal of the second FET are connected, and the gate-source capacitance and gate-drain capacitance of the second FET are used as a variable capacitance element. The microwave oscillator according to item 1. (6) Connect the second FET to the first gate terminal of the first FET.
4. The microwave oscillator according to claim 3, wherein a resonant circuit is connected to the resonant circuit, and the resonant circuit is a series resonant circuit including an inductor and a variable capacitance element of the second FET. (7) First gate terminal of first FET and second FET
2. The microwave oscillator according to claim 1, wherein a common gate bias voltage is applied to the first gate terminal and the second gate terminal. (8) Make the first FET a grounded drain type, and
7. The microwave oscillator according to claim 6, wherein the impedance when looking from the first gate terminal of T to the first FET side is negative resistance. (9) Make the first FET a common source type, and
7. The microwave oscillator according to claim 6, wherein the impedance viewed from the first gate terminal to the first FET side is negative resistance.