JPS6313564B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coaxial stripline converter for converting between a coaxial line and a stripline used in microwave and millimeter wave frequency bands.

Due to impedance discontinuities caused by discontinuous portions of conventional coaxial striplines of this type, wide-band impedance matching has been difficult.

FIG. 1 shows a cross-sectional view of a conventional coaxial strip transducer. In FIG. 1, the coaxial line is composed of a center conductor 1, an outer conductor 2, and a dielectric 3, and the stripline is composed of a strip circuit conductor 4,
Ground conductor 5, dielectric substrate 6, case 7 and lid 8
The center conductor 1 and the strip circuit conductor 4 are connected by a ribbon 9.

FIG. 2 is a cross-sectional view taken along the line AA' in FIG. 1.
As shown in this figure, because impedance conversion occurs rapidly, a discontinuity occurs at the connection between the coaxial line and the strip circuit conductor, and this discontinuity causes impedance mismatch, resulting in a narrow band. It was hot.

An object of the present invention is to provide a coaxial microstrip transducer that eliminates these discontinuities and performs impedance matching over a wide band.

This will be explained in detail below using the drawings.

FIG. 3 shows an embodiment of the present invention, and FIG.
~g are sectional views of various parts taken along lines A-A' to G-G' in FIG. 3 and 4, the outer conductor 2 is connected to the conversion outer conductor 11, the center conductor 1 is connected to the conversion inner conductor 10, and the conversion outer conductor 1 is connected to the conversion inner conductor 10.
1 is gradually cut off along the direction of propagation of the radio waves, and its area (referred to as impedance gap 12) increases.

On the other hand, in the conversion inner conductor 10, the inner conductor 10
The inner conversion conductor 10 is eccentrically and reshaped along the direction of propagation of radio waves so as not to cause a line impedance mismatch between the inner converter conductor 10 and the outer converter conductor 11 .

This modified conversion inner conductor 10 is connected to the strip circuit conductor 4 of the microstrip line, and the remaining conversion conductor 11 after cutting is connected to the ground conductor 5.
This eliminates discontinuous impedance mismatch in the converter. In this way, when a coaxial line is converted to a microstripline while maintaining the same impedance relationship, impedance matching can be realized over a wide band by removing impedance discontinuities.

As in the embodiment in FIG.
The position of the impedance gap 12 provided in the microstrip circuit is on the side opposite to the ground conductor of the microstrip circuit. The size and shape of the coaxial line are gradually increased either continuously or in steps within a range that maintains the same impedance relationship with the inner conductor, and the cut portion of the coaxial line corresponds to the outer conductor. It is characterized by gradually widening.

This impedance gap 12 is formed by the outer conductor 1
1 and a lid 8, and the manufacturing method is easy in that the lid 8 can be shared. The impedance gap 12 is in contact with the conversion outer conductor 11, the lid 8, and the conversion inner conductor 10, and the supporting method is also easy. Therefore, the coaxial stripline transducer of the present invention is characterized by easy manufacture due to the structure of the impedance gap.

The impedance gap 12 may be an air gap or may be made of a dielectric material.

In Figures 3 and 4, gaps and height deviations between the conversion outer conductor 12 and the microstrip ground conductor 5 are not shown, but in reality, even if they exist to some extent, the same effect can be obtained. can be obtained. This means that the present invention can also be applied to suspended strip lines in which dielectric substrates having microstrips are shifted in the height direction.

As described above, the coaxial microstrip converter of the present invention is easy to manufacture, and since the impedance discontinuous portion of the coaxial microstrip converter is removed, it is possible to maintain good impedance matching over a wide band while coaxial Can convert circuits to microstrip circuits.

[Brief explanation of the drawing]

Fig. 1 shows a conventional coaxial microstrip transducer, Fig. 2 is a sectional view of the conventional case, Fig. 3 shows a coaxial microstrip transducer of the present invention, and Figs.
g shows a sectional view taken along line A-A' to G-G' in FIG. In the figure, 1... center conductor, 2... outer conductor, 3... dielectric, 4... strip circuit conductor,
5... Ground conductor, 6... Dielectric substrate, 7... Case, 8... Lid, 9... Ribbon, 10... Conversion inner conductor, 11... Conversion outer conductor, 12... Impedance gap.

Claims (1)

[Claims] 1. A coaxial microstrip converter for converting between a coaxial line and a microstrip, which has an outer conversion conductor and an inner conversion conductor between the coaxial line and the microstrip line, and has an outer conversion conductor and an inner conversion conductor between the coaxial line and the microstrip line. On the coaxial line side, a part of the outer conductor of the microstrip on the side opposite to the ground conductor is opened as an impedance gap, and the opening gradually becomes closer to the microstrip line toward the microstrip line. Toward the strip side, the line gradually widens continuously or in steps within the range that keeps the line impedance the same as the inner conductor, and the open part of the outer conductor is connected to the microstrip line. The conversion inner conductor is the center conductor on the coaxial line side, and is eccentric or has a shape changed toward the ground conductor side toward the microstrip line side, and is connected to the conversion outer conductor and the conversion inner conductor. A coaxial microstrip transducer characterized by having an impedance gap in contact with a conductor.