JPH04113703A - Microwave circuit - Google Patents

Abstract

PURPOSE:To avoid discontinuity of an external conductor in a microwave transmission line by making a 1st metallic case having a 2nd plane having a concentric swollen part from the inner wall of a cylinder to outside in contact with an end face of a cylindrical microwave transmission line. CONSTITUTION:A mount face 2 for a short-circuit plate 4 is provided to a metal-made case 1 having a cylindrical waveguide 5. Since it is possible to make a concentric swollen part 3 in contact with the short-circuit plate 4 at mount before the contact with the mount face 2, the contact of the short-circuit plate 4 at an inner wall end face of the circular waveguide 5 is sufficiently taken and an excellent short-circuit characteristic is ensured without being affected by profile irregularity of the mount face 2.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a microwave circuit used in microwave communication equipment, satellite broadcast reception converters, and the like.

Background of the Invention In recent years, micro-branches used in microwave communication equipment have
The progress of children is remarkable, and HEMT and MES
- Since low-noise devices such as FETs are easily available, the noise figure, especially in receiving low-noise converters, is decreasing year by year. However, even if the noise figure of the low-noise microwave element itself is good, the effects of loss and impedance mismatch between the input section and the microwave element are significant, and it is difficult to obtain the desired noise figure as a whole for the low-noise converter. There were cases where it was not possible.

Hereinafter, the conventional microwave circuit as described above will be explained with reference to the drawings.

FIG. 7 shows a conventional circular waveguide short circuit, and FIG. 8 shows a cross-sectional view thereof. In FIG. 7, ▪ is a metal housing having a circular waveguide 5, and 2 is a surface on which the short plate 4 is attached. Normally, the short plate 2 is fixed to the surface 2 with screws or the like to form a short surface. When the short plate 4 is in an ideal short circuit state, the microwave propagating through the circular waveguide 5 undergoes total reflection without loss and changes its propagation direction.

Problems to be Solved by the Invention However, in the above-mentioned configuration, due to variations in the surface precision of the surface 2 and variations in the flatness of the short plate 4, contact is not sufficient especially at the end face of the circular waveguide.
Short vi4 does not operate as a complete short surface.

Therefore, when used with the Soyot surface of a low noise converter,
Since the input power cannot be reflected sufficiently, there is a problem in that the noise figure deteriorates and the input VSWR deteriorates.

In view of the above-mentioned problems, the present invention ensures sufficient contact between the outer conductor of a first metal casing having a cylindrical microwave transmission path and a conductor having a second planar shape, and provides a microelectronic device that exhibits good characteristics. It captures and provides wave circuits.

Means for Solving the Problems In order to achieve this object, the microwave circuit of the present invention includes a first metal casing having a concentric raised portion outward from the cylindrical inner wall on the end face of the cylindrical microwave transmission line. It is constructed by bringing the body into contact with a metal casing having a second planar shape.

According to the above-described structure, the present invention makes contact with the metal casing having the second planar shape within a narrow range of only the raised portion provided on the outside of the cylindrical inner wall of the first metal cylinder. Sufficient electromagnetic contact can be made between the two, ensuring good characteristics.

EXAMPLE A microwave circuit according to an example of the present invention will be described below with reference to the drawings.

FIG. 1 shows a circular waveguide short-circuit portion of the present invention, and FIG. 2 shows a cross-sectional view thereof. In the first time, 1 is a metal housing having a circular waveguide 5, and 2 is a surface on which the short plate 4 is attached. The microwave propagating in the circular waveguide 5 undergoes total reflection without loss and changes its propagation direction if the short circuit state at the short plate 4 is sufficient. In this example,
The short plate 2 can be attached to the end surface of the inner wall of the circular waveguide 5, which is important when realizing a short surface, because it is possible to make contact with the concentric raised portion 3 before contacting the surface 2. Since the shorting plate 4 is in sufficient contact with the shorting plate 4, the mounting is not affected by the surface precision of the surface 2, and good shorting characteristics can be ensured. Furthermore, even if the short plate 4 does not have such high flatness, a good short plate can be realized because the short plate 4 contacts the inner wall of the circular waveguide 5 before it comes into contact with the surface 2. .

Other embodiments of the present invention will be described below with reference to the drawings. FIG. 3 shows a circular waveguide short-circuit portion in another embodiment of the present invention, and FIG. 4 shows a cross-sectional view thereof.

In FIGS. 3 and 4, 10 is a metal housing having a circular waveguide 12, 2 is a surface on which the short plate is attached, and 11 is a concentric raised portion. In this embodiment, processing is made easier by changing the cross-sectional shape of the concentric raised portion 11, and as in the previous embodiment, it is not affected by the surface accuracy of the contact surface 2, and the short plate 4 has a concentric circular shape. By contacting the shaped raised portion 11, the short-circuited surface of the circular waveguide 12 can ensure sufficiently good characteristics.

Further, second and third embodiments of the present invention will be described with reference to the drawings. FIGS. 5 and 6 are cross-sectional views of a circular waveguide-microstripe line conversion section in another embodiment of the present invention.

10 is a metal conductor having a circular waveguide 12, 6 is a post fitting, 7 is an MTC board having a microstrip line, 8 is a metal supporter for forming a hollow coaxial line with the post fitting 6, A dielectric supporter 9 forms a dielectric coaxial line with the post metal fitting 6.

In FIGS. 5 and 6, the microwave propagating in the circular waveguide 12 in the direction perpendicular to the plane of the paper is converted into a coaxial mode at the post fitting 6, and propagates through the coaxial line formed by 9 and 8. , mode conversion is further performed at the junction between the MIC substrate 7 and the post fitting 6, and the signal propagates through the microstrip line on the MIC substrate 7.

In the waveguide-microstripe line conversion section as described above, if there is insufficient contact between the metal spacer 8 and the metal casing 10, each formed by the metal spacer 8 and the dielectric supporter 9 The discontinuity of the outer conductor in the coaxial line causes loss and VSWR deterioration during microwave propagation. Therefore, by providing the concentric raised portion 10 on the metal casing 1 side in FIG. 5 and on the metal support 8 side in FIG. Good propagation characteristics can be ensured.

As described above, according to this embodiment, by providing a concentric raised portion on the outer conductor forming one coaxial line and bringing it into contact with the outer conductor of the other coaxial line, a discontinuous portion is created in the coaxial outer conductor. It is possible to prevent loss and V S WR deterioration due to the occurrence of the noise.

Effects of the Invention The present invention as described above includes a metal casing having a first metal casing having a concentric circular protuberance extending outward from a cylindrical inner wall on the end face of a cylindrical microwave transmission line, and a metal casing having a second planar shape. By making contact, discontinuities in the outer conductor portion in the microwave transmission path can be eliminated and good transmission characteristics can be provided, and the effect is quite large.

5 and 6 are cross-sectional views of the second, eleventh, and
...Concentric raised part, 4 ... Short plate, 512 ... Circular waveguide, 6 ... Post metal fitting, 7 ... MIC Substrate, 8...Metal supporter, 9...Dielectric supporter.

Name of agent: Patent attorney Akira Okaji and 2 others

[Brief explanation of drawings]

No. figure

Claims (1)

[Claims] A first metal casing having a concentric circular protuberance outward from the cylindrical inner wall on the end face of the microwave transmission line obtained by cutting the inner side into a cylindrical shape, and a second metal casing having a planar shape.
A microwave circuit characterized by sufficient contact between the metal casings.