JPS6213105A - Monolithic microwave fet oscillator - Google Patents

Abstract

PURPOSE:To use the titled oscillator as both a VCO or a dielectric resonator frequency stabilizing oscillator without changing a circuit parameter by coupling a dielectric resonator to a specific location on a microstrip line of a 50OMEGA characteristic impedance provided in series with one end of the microstrip line. CONSTITUTION:The monolithic VCO consists of a FET 4, the 1st microstrip line 12, a source feedback microstrip line 22 and matching circuits 32a, 32b and is constituted in one semiconductor chip. On the other hand, the dielectric resonator circuit consists of a dielectric resonator 14, the 2nd 50OMEGA microstrip line 13 and a harmonic mode oscillation preventing 50OMEGA resistor 5 and is constituted on one ceramic base. The oscillator acts like a VCO by connecting the 1st microstrip line 12 to an earth 17 (point A) in terms of microwave. In connecting the line 12 to a point B, the oscillator keeps the operation at omega0.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a FET oscillator having a monolithic microwave IC configuration.

In recent years, with the advancement of technologies such as satellite broadcasting, radar, and microwave communication, the demand for stain pressure controlled oscillators (hereinafter referred to as VCOs) and frequency stabilized microwave oscillators has increased. For this purpose, a monolithic microwave using GaAs FgT
Developments of CO and dielectric resonator stabilized oscillators are underway everywhere.

(Problems with conventional technology) In monolithic microwave CO, the impedance of the circuit provided between the FIT gate terminal and ground, and between the source terminal and ground is optimized in order to achieve maximum power in the desired frequency band. There is. In order to stabilize the frequency of such CO, a method is generally used in which a dielectric resonator circuit is coupled to the gate terminal. However, in the conventional oscillator structure, adding a resonator circuit changes the impedance tit of the gate circuit, making it impossible to maintain the optimum value. For this reason, conventionally, in order to stabilize the frequency of the VCO, it was necessary to significantly modify each circuit parameter of the excavator, and it was necessary to rebuild the entire IC.

(Objective of the Invention) The object of the invention is to eliminate the above-mentioned drawbacks and to create a monolithic microwave)'ET oscillator that can be used both as a VCO and as a dielectric resonator frequency-stabilized oscillator without changing the circuit parameters. It is about making things possible.

(Structure of the Invention) According to the present invention, in a series feedback monolithic microwave FET oscillator provided with a first microstrip line whose one end is microwave-shorted to the gate of the FET, the first microstrip line A second 500 characteristic impedance microstrip line is provided in series at the other end of the IJ tube line, and (2K+1)/4 is connected from the connection point of the first microstrip line and the second microstrip line. Wavelength (however, 2O, 1, 2,...
...) A monolithic microwave FET oscillator characterized in that a dielectric resonator is coupled to a location on the +7-pin line is obtained.

(Detailed Description of the Invention) FIG. 4 shows a conventional microwave FgT VCO and dielectric resonator stabilized oscillator.

In the conventional method, the microstrip line 1 of the gate circuit is replaced with a dielectric resonator circuit 11, and the source feedback line 2 and matching It was necessary to redesign and remanufacture circuits 3(a), 3 (bl is also 21.3 Ha each), and 31 directions.

FIG. 1 shows the configuration of a monolithic microwave vCO that does not require redesign and can be frequency stabilized according to the present invention.

In the figure h, the monolithic VCO is FET4. First microstrip line 12. It consists of a source feedback microstrip line 22 and match ink circuits 32 (a) and 32 (1)), and is constructed in one semiconductor chip.

On the other hand, the dielectric resonator circuit includes a dielectric resonator 14, a second 50
Ω microstrip line 13 and five 500 resistors for preventing high-order mode oscillation), and is constructed on a single ceramic substrate. FIG. 2 shows the equivalent circuit and operating principle of the dielectric resonator circuit. In the figure, the dielectric resonator has a fundamental resonance angular frequency ω.

force expressed as a parallel resonant circuit 15) ω, then 0
The impedance looking to the left from the point is infinite.

This infinite impedance '2(2K+1)wavelength/4
When converted by the microstrip line 16 having a length of , the oscillator operates as a VCO by connecting the impedance Z seen to the left from point B to the ground 17 (point A) in a microwave manner. The intersection of the circuit impedance Φ locus ZC (ω) viewed to the left from point D at that time and the device line Zd viewed to the right represents the oscillation operating point. Third (
a) As shown in the Smith chart in the figure, by changing V, Zd rotates on the Smith chart and the intersection with ZC(ω) moves. This changes the oscillation frequency.

If the first microstrip connector 12 is removed from point A and connected to point B, ω as described above.

Since the impedance Z seen from point B is zero, Zc(
ω, ) maintains its previous value. Therefore, the oscillator keeps operating at ω. ZC(ω), which has a high Q (quality factor) at ω due to the dielectric resonator circuit, becomes a circle with a fairly small frequency change near ω on the Smith chart in Figure 3(b). . Therefore, even if the device line Zd rotates.

The frequency at the intersection of ZC(ω) and Zd remains almost unchanged. This means that the oscillator is stabilized at the oscillation frequency ω.

(Effects of the Invention) According to the present invention, the monolithic microwave oscillator can be used as a VCO by connecting its gate circuit to the microwave ground, and frequency stabilization can be achieved by connecting the gate circuit to a dielectric resonant circuit. Can be used as an oscillator. Therefore, when redesigning, one monolithic microwave oscillator can be used both as a VCO and as a stabilizing oscillator, and the number of design steps and prototyping steps can be significantly reduced.

[Brief explanation of drawings]

Figure 1 shows a dielectric resonator stabilized molithic microwave oscillator of the present invention, and Figure 2 shows a dielectric resonator circuit,
Fig. 3 is an explanation of the impedance locus and device line of vCO and stabilizing oscillator, and Fig. 4 is the conventional VCO
CO and stabilized oscillator.・ In the figure, 1 and 12 are gate circuit microstrip lines, and 2.21 and 22 are source feedback microstrip lines! J y 7fmF11r, 3fa), 31fa
), 32 (al, 3 (1)), 31 (b) 3
2(b) is a matching circuit, 4 is a FET, II,
13゜16 is the microstrip line of the resonator circuit, 1
4 is a dielectric resonator, 15 is its parallel equivalent circuit, 5 is a 50Ω resistor for preventing higher-order mode oscillation, 17 is a microwave earth %18 Hassmith chart, 19 and 20 are the VCO device line and , Impedance Locus %29 Stabilized Oscillator Impedance Locus 2
Figure 71-3 Figure (b)

Claims (1)

[Claims] The first one has one end microwave shorted to the gate of the FET.
In a series feedback monolithic microwave FET oscillator provided with a microstrip line, a second microstrip line with a characteristic impedance of 50Ω is provided in series at the other end of the first microstrip line, and and a dielectric resonator is coupled to a location on the second microstrip line that is (2K+1)/4 wavelengths (K=0, 1, 2...) away from the connection point of the second microstrip line. A monolithic microwave FET oscillator characterized by: