Equivalent Susceptance of a Circular Iris in a Parallel Plate Waveguide

Hiroaki MIYASHITA  Isamu CHIBA  Shuji URASAKI  Shoichiro FUKAO  

IEICE TRANSACTIONS on Communications   Vol.E82-B   No.11   pp.1844-1850
Publication Date: 1999/11/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Communication Cable and Wave Guides
iris,  circular iris,  parallel plate waveguide,  equivalent susceptance,  approximate formula,  

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An approximate formula is proposed for the equivalent susceptance of a circular iris in a parallel plate waveguide when the TEM mode cylindrical wave is incident from the center of the iris. Schwinger's variational method for a linear iris is generalized to the cylindrical case, and an approximate closed form formula is obtained which recovers the result of the linear iris when the radius of the circular iris is sufficiently larger than the wavelength. For verification of the formula, an exact integral equation is formulated and solved numerically by Galerkin's method. A comparison between them shows good agreement.