NON-RECIPROCAL CIRCUIT DEVICE

Abstract

A non-reciprocal circuit device comprising a metal case, a ground plate disposed on an inner bottom surface of the metal case, a resin member disposed on the ground plate and having an opening from which the ground plate is exposed, a planar microwave ferrite member disposed in the opening of the resin member, a strip line member disposed on the planar microwave ferrite member, and a permanent magnet disposed with distance on the strip line member without another planar microwave ferrite member therebetween, the strip line member comprising a connecting portion constituted by strip electrodes radially extending from a center portion, and branch lines radially extending from the center portion between the strip electrodes, low-impedance lines each integrally connected to each of the branch lines and extending along the periphery of the planar microwave ferrite member, and electrodes each integrally connected to each of the low-impedance lines, whereby the branch lines and the ground plate forms microstrip lines, and the low-impedance lines and the ground plate forms a grounded capacitor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing the appearance of a non-reciprocal circuit device according to one embodiment of the present invention.

FIG. 2 is an exploded perspective view showing the internal structure of a non-reciprocal circuit device according to one embodiment of the present invention.

FIG. 3 is a cross-sectional view taken along the line A-A in FIG. 1.

FIG. 4 is a plan view showing one example of a microstrip line member used in a non-reciprocal circuit device according to one embodiment of the present invention.

FIG. 5 is a graph showing the insertion loss characteristics of a non-reciprocal circuit device according to one embodiment of the present invention.

FIG. 6 is a graph showing the input return loss characteristics of a non-reciprocal circuit device according to one embodiment of the present invention.

FIG. 7 is a graph showing the isolation characteristics of a non-reciprocal circuit device according to one embodiment of the present invention.

FIG. 8 is a graph showing the output return loss characteristics of a non-reciprocal circuit device according to one embodiment of the present invention.

FIG. 9 is a graph showing the relation between insertion loss and a gap between a permanent magnet and a microstrip line member in the non-reciprocal circuit device according to one embodiment of the present invention.

FIG. 10 is a plan view showing the internal structure of a conventional non-reciprocal circuit device.

FIG. 11 is a cross-sectional view taken along the line B-B in FIG. 10.

FIG. 12 is a perspective view showing the appearance of another conventional non-reciprocal circuit device.

FIG. 13 is an exploded perspective view showing the internal structure of another conventional non-reciprocal circuit device.

FIG. 14 is a perspective view showing the appearance of a further conventional non-reciprocal circuit device.

FIG. 15 is an exploded perspective view showing the internal structure of the conventional non-reciprocal circuit device of FIG. 14.

Claims

1. A non-reciprocal circuit device comprising a metal case, a ground plate disposed on an inner bottom surface of said metal case, a resin member disposed on said ground plate and having an opening from which said ground plate is exposed, a planar microwave ferrite member disposed in the opening of said resin member, a strip line member disposed on said planar microwave ferrite member, and a permanent magnet disposed with distance on said strip line member without another planar microwave ferrite member therebetween, said strip line member comprising a connecting portion constituted by strip electrodes radially extending from a center portion, and branch lines radially extending from said center portion between said strip electrodes, low-impedance lines each integrally connected to each of said branch lines and extending along the periphery of said planar microwave ferrite member, and electrodes each integrally connected to each of said low-impedance lines, whereby said branch lines and said ground plate forms microstrip lines, and said low-impedance lines and said ground plate forms a grounded capacitor.

2. The non-reciprocal circuit device according to claim 1, wherein a partition member is disposed between said strip line member and said permanent magnet to keep their gap.

3. The non-reciprocal circuit device according to claim 2, wherein said partition member has a flange for supporting a sidewall of said permanent magnet.

4. The non-reciprocal circuit device according to claim 2, wherein said partition member is made of a heat-resistant resin.

5. The non-reciprocal circuit device according to claim 1, wherein the gap between said strip line member and said permanent magnet is equal to or larger than the thickness of said planar microwave ferrite member.