A Novel 180-Degree 3 dB Hybrid Using a Cylindrical Cavity

Mitsuyoshi KISHIHARA  Tadashi KAWAI  Yoshihiro KOKUBO  Isao OHTA  

IEICE TRANSACTIONS on Electronics   Vol.E82-C    No.7    pp.1148-1153
Publication Date: 1999/07/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Microwave and Millimeter Wave Technology)
Category: Passive Devices and Circuits
waveguide,  waveguide component,  E-plane planar circuit,  hybrid,  

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This paper suggests a new type of 180-degree 3 dB hybrid, which consists of a cylindrical cavity and four E-plane rectangular waveguides radially coupled with it, and shows that good hybrid properties are realized by modifying the positions of the four input/output waveguides and the radius of the cylindrical cavity that are determined by the field distribution of the TE111 resonant mode. Moreover, a method of broadening the bandwidth with additional impedance steps is described. The present hybrid is marked by simple structure, and hence is useful for applications at millimeter wave frequencies and to high-power microwave systems. Experimental verification is additionally shown.