Scattering of TM Plane Wave from Periodic Grating with Single Defect

Kazuhiro HATTORI  Junichi NAKAYAMA  Yasuhiko TAMURA  

IEICE TRANSACTIONS on Electronics   Vol.E91-C   No.1   pp.17-25
Publication Date: 2008/01/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e91-c.1.17
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Recent Progress in Electromagnetic Theory and Its Application)
Category: Scattering and Diffraction
scattering,  periodic grating,  defect,  TM plane wave,  rectangular grooves,  incoherent Wood's anomaly,  guided surface wave,  

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This paper deals with the scattering of a TM plane wave from a periodic grating with single defect, of which position is known. The surface is perfectly conductive and made up with a periodic array of rectangular grooves and a defect where a groove is not formed. The scattered wave above grooves is written as a variation from the diffracted wave for the perfectly periodic case. Then, an integral equation for the scattering amplitude is obtained, which is solved numerically by use of truncation and the iteration method. The differential scattering cross section and the optical theorem are calculated in terms of the scattering amplitude and are illustrated in figures. It is found that incoherent Wood's anomaly appears at critical angles of scattering. The physical mechanisms of Wood's anomaly and incoherent Wood's anomaly are discussed in relation to the guided surface wave excited by the incident plane wave. It is concluded that incoherent Wood's anomaly is caused by the diffraction of the guided surface wave.