JPH061862B2 - Microwave integrated circuit - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave integrated circuit (abbreviated as MIC) used in a frequency converter of a microwave communication device or an SHF receiver.

Configuration of Conventional Example and Problems Thereof When a frequency mixer is formed by forming a frequency mixer and a local oscillator on an MIC substrate, a dielectric resonator is usually used for the local oscillator. On the other hand, the frequency converter is arranged in the metal housing, but at this time, the dielectric resonator used in the local oscillator and the waveguide mode resonating in the metal housing are coupled, and the oscillation of the local oscillator is stopped. Alternatively, it appears as a phenomenon that the diode current of the frequency mixer is extremely decreased, which is considered to be due to the decrease of the oscillation output.

In order to avoid such coupling between the dielectric resonator and the waveguide mode of the metal housing, place the entire local oscillator including the dielectric resonator in a metal housing different from the metal housing of the frequency converter. First place and then place the local oscillator and frequency mixer in one metal housing, or house only the dielectric resonator in the metal housing, and then place the local oscillator and frequency mixer in another metal housing. Conventionally, the method of placing it inside the body has been taken.

However, in the conventional method in which the metal casing is duplicated, two types of metal casings are required, which not only complicates the configuration of the metal casing, but also uses the inner metal casing to integrate microwaves around the casing. There are drawbacks that the circuit configuration is restricted by various arrangements and the size of the outer metal casing becomes very large.

OBJECT OF THE INVENTION It is an object of the present invention to remove an inner metal housing that surrounds only a local oscillator or only a dielectric resonator, and to remove a dielectric resonator and an outer metal housing that occur when the metal housing is removed. Another object of the present invention is to provide an MIC that can easily prevent coupling with a waveguide mode that resonates with.

Configuration of the Invention In the present invention, the local oscillator and the frequency mixer are arranged in the same metal housing, and the metal plate is arranged at an appropriate position in the metal housing.

Description of Embodiments Embodiments of the present invention will be described below with reference to the drawings.

1 (a) and 1 (b) are views showing an embodiment of a microwave integrated circuit according to the present invention. FIG. 1 (a) is a plan view and FIG. 1 (b) is a sectional view. GaAs arranged on the microwave integrated circuit board 1
The FET 2 and the dielectric resonator 3 form a local oscillator 4. The frequency mixer 5 is formed on the same microwave integrated circuit substrate 1 as the substrate on which the local oscillator 4 is formed, but the frequency mixer 5 is mainly composed of three end open stubs 6. It is composed of a signal blocking filter 7 and a mixer diode 8. Reference numeral 9 denotes a rectangular metal housing, and in the metal housing 9, a frequency converter 10 including a local oscillator 4 and a frequency mixer 5 is arranged.
Reference numeral 12 denotes a metal plate, which is arranged in the vicinity of the image signal blocking filter 7 so as to project from the inner wall surface of the metal housing 9 so as to partition the ends of the two open-ended stubs 6 closest to the mixer diode 8.

For example, the dielectric resonator 3 (resonance frequency is 10.75 GHz) is placed in a metal housing 9 of 60 × 30 × 9 mm near the lower right corner of the metal housing 9 as shown in FIG. 2 mm in thickness, 6 mm in length, and 6 mm in height when the end opening stub 6 of the image blocking filter 7 is arranged so as to be orthogonal to the inner wall surface side wall of the metal housing 9. 8 mm
As shown in FIG. 1 (a), the metal plate 12 of the mixer diode 8 is placed at a position about 17 mm away from the upper left corner of the metal housing 9 to the right.
It is confirmed that the local oscillator 4 operates normally and the diode current also flows normally by arranging so as to partition the tips of the two open-ended stubs 6 closest to the inner wall surface of the metal casing 9 so as to partition the tip. It was

As a result of experimenting the operation of the diode current by changing the position and size of the metal plate 12, the most stable diode current flowed at the position shown in FIG.

In the embodiment shown in FIGS. 1 (a) and 1 (b), the metal casing 9 is provided by protruding the inner wall surface of the metal casing 9 and disposing the metal plate 12.
It is possible to suppress the coupling of the waveguide mode that resonates in the metal housing 9 and the resonance mode of the dielectric resonator 3 in addition to changing the mode that resonates inside, and also to partition the tip of the open-ended stub 6. With this arrangement, the coupling between the stop band frequency of the image blocking filter 7 (including the frequency of the local oscillator 4) and the waveguide mode resonating in the metal housing 9 is also suppressed at the same time. Due to the adverse effect of the characteristics of the image blocking filter 7 at the output frequency from the metal housing 9, the impedance of the local oscillator 4 as seen from the frequency mixer 5 changes, and the mixer / diode 8 is supplied with sufficient power of the local oscillator 4. This has the effect of eliminating the adverse effect of not being performed. In addition, the metal plate 12 is a stub 6 with an open end.
Since it is arranged so as to partition the tip of the image blocking filter 7, the coupling between the open stubs 6 of the image blocking filter 7 can be reduced, and the waveguide mode in the metal housing 9 and the image frequency of the image blocking filter 7 can be reduced. Since the coupling can also be suppressed, there is an effect that the adverse effects of the conversion loss characteristic and the image suppression ratio characteristic of the frequency converter 10 from the metal housing 9 can be eliminated.

2 (a) and 2 (b) are views showing still another embodiment of the microwave integrated circuit according to the present invention. FIG. 2 (a) is a plan view and FIG. 2 (b) is a sectional view. The same parts as those shown in FIGS. 1A and 1B are designated by the same reference numerals for description. The GaAs FET 2 and the dielectric resonator 3 arranged on the microwave integrated circuit substrate 1 are used for the local oscillator 4
Is configured. A frequency mixer 5 is provided on the same microwave integrated circuit board 1 on which the local oscillator 4 is formed.
The frequency mixer 5 is mainly composed of an image signal blocking filter 7 composed of three open-ended stubs 6 and a mixer diode 8.
Reference numeral 9 denotes a rectangular metal case, and the local oscillator 4 is provided in the metal case 9.
A frequency converter 10 including a frequency mixer 5 and a frequency mixer 5 is arranged. Reference numeral 12 denotes a metal plate, which is arranged in the vicinity of the image signal blocking filter 7 so as to project from the inner wall surface of the metal housing 9 so as to partition the ends of the two open-ended stubs 6 closest to the mixer diode 8. Reference numeral 11 is a radio wave absorber, which is located on the side of the metal plate 12 (on the side opposite to the dielectric resonator 3),
It is arranged along the inner wall surface of the metal housing 9 and near the image signal blocking filter 7.

In addition to the effect of the embodiment of FIG. 1, the embodiment of FIGS. 2 (a) and 2 (b) further effectively suppresses the waveguide mode resonating in the metal casing 9 by the radio wave absorber 11. It In addition, when viewed from the position of the dielectric resonator 3, the position of the radio wave absorber 11 is arranged so as to cover the back of the metal plate 12 and apart from the dielectric resonator 3. The resonance electromagnetic field of the container 3 is not affected by the radio wave absorber 11. Further, since the radio wave absorber 11 is arranged in the vicinity of the image signal blocking filter 7, the coupling between the image signal blocking filter 7 and the waveguide mode resonating in the metal housing 9 is suppressed more effectively, The effect of removing the adverse effects of the conversion loss characteristic and the image suppression ratio characteristic of the frequency converter 10 from the metal casing 9 is further improved.

As described above, according to the present invention, the metal plate is projected from the inner wall surface of the metal housing in the vicinity of the image signal blocking filter so as to partition the ends of the two open-ended stubs closest to the mixer diode. By arranging it, the coupling between the waveguide mode that resonates in the metal housing and the dielectric resonator is suppressed, abnormal operation of the local oscillator can be prevented, and the waveguide mode that resonates in the metal housing can be prevented. The coupling with the image blocking filter is also suppressed at the same time, and the adverse effects of the conversion loss characteristic and the image suppression ratio characteristic of the frequency converter from the metal housing can be eliminated.

Further, the local oscillator output is efficiently added to the mixer diode, and a sufficient mixer current flows, so that a stable frequency conversion circuit can be configured, and the local oscillation output can be small.
Local signal leakage to the input side is also reduced.

[Brief description of drawings]

1 (a) and 1 (b) are a plan view and a sectional view showing a microwave integrated circuit according to an embodiment of the present invention, and FIGS. 2 (a) and 2 (b) are microwaves according to another embodiment of the present invention. It is the top view and sectional drawing which show a wave integrated circuit. 1 ... Microwave integrated circuit board, 3 ... Dielectric resonator,
4 ... Local oscillator, 5 ... Frequency mixer, 6 ... End open stub, 7 ... Image signal blocking filter, 9 ... Metal housing, 10 ... Frequency converter, 11 ... Radio wave absorber,
12 …… Metal plate.

Claims (2)

[Claims] 1. A local oscillator whose oscillation frequency is controlled by a dielectric resonator and a frequency mixer including an image signal blocking filter composed of a plurality of open-ended stubs are formed on a microwave integrated circuit board. , The microwave integrated circuit board is arranged in the same metal housing, a metal plate is arranged so as to project to an inner wall surface in the metal housing, and the tips of the plurality of end opening stubs are partitioned by the metal plate, A microwave integrated circuit, wherein a plurality of open-ended stubs partitioned by the metal plate are selected as two open-ended stubs closest to the mixer diode of the frequency mixer. 2. The microwave integrated circuit according to claim 1, wherein the electromagnetic wave absorber is arranged in the vicinity of the image signal blocking filter.