Diffraction of Cylindrical Wave by Smooth and Polygonal Cylinders

Hiroshi SHIRAI  Kohei HONGO  Hirokazu KOBAYASHI  

IEICE TRANSACTIONS (1976-1990)   Vol.E66   No.2   pp.116-123
Publication Date: 1983/02/25
Online ISSN: 
Print ISSN: 0000-0000
Type of Manuscript: PAPER
Category: Antenna and Propagation

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Expressions are derived for estimating the scattered and diffracted field in the presence of the polygonal cylinder using high frequency technique which is closely related with equivalent current or equivalent moment method proposed formerly. As the first step, we verified the method by applying it to various kinds of polygonal cylinders. The numerical results for radiation patterns are compared with those obtained by other methods when they are available. The agreement between them is fairly good and difference between them is not recognised in the figures except in a small part of region where observation point lies near a shadow boundary of the polygonal cylinder. The discrepancy is few decibels. Next we study a possibility of estimating the diffracted field of smooth convex cylinder by approximating it with corresponding polygonal cylinder. As an illustration we consider radiation of electric and magnetic line source in the presence of conducting circular cylinder since the exact solution of the problem is readily obtained. The approximation of smooth object with corresponding edged object is found to be useful from the standpoint of diffraction. The method is also applied to estimate the diffracted field by curved wedge and curved half plane.