JPH0632418B2 - Microwave integrated circuit - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a structure of a housing that houses a circuit in a microwave integrated circuit configured using an alumina ceramic substrate or the like.

[Conventional technology]

Conventionally, a microwave integrated circuit is configured by using active elements such as transistors and diodes or passive elements such as resistors and capacitors in a circuit mainly composed of a microstrip line. Since signals are connected to each other by a coaxial cable or a waveguide, microstrip-coaxial conversion or microstrip-waveguide conversion using a connector or the like is used.

By the way, the microwave propagation mode in a microwave integrated circuit mainly composed of a microstrip line having such a structure is, of course, a microstrip mode, but the original microstrip mode is sufficient for the propagation wavelength. It has a wide ground contact surface and space. However, when the microwave circuit is housed in such a fixed housing, the housing itself can be regarded as a fixed waveguide, so that a phenomenon such as signal propagation or resonance in the waveguide mode as an unnecessary mode occurs, The original operation may not be performed sufficiently.

What has been conventionally used to deal with such a point is that the structure of the housing itself is a cut-off waveguide to prevent signal propagation in the waveguide mode.

FIG. 5 is a cross-sectional view showing such a conventional microwave integrated circuit housing, which is a cross section in a direction perpendicular to a signal transmission line. In the figure, (1) is an outer housing, (2) is a dielectric substrate that constitutes a microwave circuit, (3) is a metal carrier, (4) is an inner metal cover, and (5) is an outer lid. The transmission line of is formed on the dielectric substrate (2). Inner Metal Cover (4)
The distance between the walls facing each other is set to 1/2 or less of the propagation wavelength, which is sufficiently cut off for TE ₁₀ wave which is the fundamental mode of the rectangular waveguide, and inside the inner metal cover (4). In, no signal propagates in the waveguide mode.

[Problems to be solved by the invention]

However, in the case of such a structure, a certain gap still remains between the inner metal cover (4) and the outer lid (5), and the radio wave leaked to the outside from the end of the inner metal cover (4) is also There is a problem in that it can propagate inside the external housing (1) and can affect the characteristics of the microwave circuit.

The present invention has been made to solve such a problem, and an object thereof is to obtain a microwave integrated circuit capable of preventing radio wave propagation in a slight gap.

[Means for solving problems]

The microwave integrated circuit according to the present invention uses the principle of the cutoff waveguide as in the conventional method,
A plurality of conductive elastic members are inserted between the inner metal cover and the lid of the outer casing covering the same along the signal propagation direction at required intervals to ensure electrical connection between the two. .

[Action]

In the microwave integrated circuit according to the present invention, the inner metal cover acts as a cut-off waveguide as in the conventional case, and a plurality of conductive elastic members are provided between the inner metal cover and the lid of the outer casing along the signal propagation direction at a required interval. , The radio wave does not propagate in the slight gap between them.

Example of Invention

FIG. 1 is a partially cutaway plan view showing a first embodiment of the present invention, and FIG. 2 is a sectional view taken along line II-II of FIG. In this embodiment, as can be seen in FIG. 2, by inserting a spring material called a finger (6) between the inner metal cover (4) and the outer lid (5), there is a problem in the conventional structure. The cut-off waveguide is used to eliminate the radio wave propagation due to the slight gap.

This finger (6) is made of an elastic material such as phosphor bronze. As shown in the plan view of Fig. 3 (a) and the side view of Fig. 3 (b), the direction of signal propagation is shown. It works effectively to keep the upper and lower electrical contact at a fine interval.

Further, by providing a groove on the upper surface of the inner metal cover (4) as shown in this embodiment, the finger (6) can be fixed at a fixed position.

In this embodiment, the microstrip line (2) is covered with a cover (4) such that the distance between the opposing walls is not more than 1/2 of the propagating signal wavelength. ) Suppresses the propagation of signals due to unnecessary modes, and
Radio waves leaking from a gap (eg (7)) at the edge of the cover (4) are also propagated by a spring material between the cover (4) and the outer lid (5) in the direction perpendicular to the signal propagation direction. 1 / wavelength
The fingers (6) configured so as to have the number of 2 or less are arranged, and the electrical contact between the outer lid (5) and the inner metal cover (4) is maintained to prevent the propagation.

A second embodiment of the present invention is shown in FIG. In this embodiment, as in the first embodiment, the outer lid (5) and the inner metal cover are
The gap with (4) is also used as a cutoff waveguide, but a groove is provided in the outer lid (5) and a conductive rubber (8) is attached in the groove, while the inner metal cover is attached. When the protrusion is provided along the groove of the outer lid (5) on the (4) side and the lid is covered, the protrusion of the inner metal cover (4) and the conductive rubber (8) are brought into contact with each other. The same effect can be obtained.

Although the microwave integrated circuit using alumina ceramics or the like has been described in the above embodiment, the present invention can be easily realized in a microwave circuit or the like using an ordinary printed circuit board or the like.

〔The invention's effect〕

As described above, according to the present invention, between the inner metal cover that wraps the microwave circuit and the lid of the outer housing that wraps the inner metal cover,
Since the conductive elastic body is inserted along the propagation direction of the microwave signal with a pitch of 1/2 or less of the microwave wavelength to ensure the conductivity between the two, it is possible to eliminate the propagation of the signal wave in the unnecessary mode. Thus, a microwave integrated circuit without deterioration of characteristics can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially cutaway plan view showing a first embodiment of the present invention, FIG. 2 is a sectional view taken along line II-II, and FIG. A plan view of a finger used for this, FIG. 4 (b) is a side view thereof, FIG. 4 is a sectional view showing a second embodiment of the present invention, and FIG. 5 is a sectional view showing a conventional microwave integrated circuit. is there. In the figure, (1) is an outer housing, (2) is a dielectric substrate, (3) is a metal carrier, (4) is an inner metal cover, (5) is an outer lid,
(6) is a finger, (7) is a gap, and (8) is a conductive rubber. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (4)

[Claims] 1. A microwave integrated circuit comprising a circuit composed of a microstrip line formed on a dielectric substrate and a circuit element such as a transistor, and an external casing accommodating the circuit, wherein: At least a part of the circuit is covered with an inner metal cover having a U-shaped cross section extending along the propagation direction of the microwave signal inside the casing, and the lid of the outer casing and the inside are covered. Between the metal cover and the propagation direction of the microwave signal, a conductive elastic body is inserted with a pitch of 1/2 or less of the microwave wavelength, and between the lid of the outer casing and the inner metal cover. A microwave integrated circuit characterized by ensuring electrical continuity. 2. A conductive elastic body is disposed in a recess provided on one of the surfaces of the outer casing facing the inner metal cover and the conductive elastic body is provided on the other of the facing surface with a projection provided with a required pitch. The microwave integrated circuit according to claim 1, wherein the elastic body is pressed. 3. The microwave integrated circuit according to claim 1 or 2, wherein a metal piece having a plurality of elastic fingers of a required pitch is used as the conductive elastic body. 4. The microwave integrated circuit according to claim 1, wherein a conductive rubber member is used as the conductive elastic body.