Publicou 12 edições por ano
ISSN Imprimir: 0040-2508
ISSN On-line: 1943-6009
Indexed in
EIGENMODES AND RESONANCE PROPERTIES OF ONEâ€DIMENSIONALLY PERIODIC METALLIC BAR GRATINGS. PART 1: CLASSICAL GRATING
RESUMO
The interest shown today toward resonance properties of perforated metal gratings has been renewed owing to the effect known as the "enhanced transmission phenomena" which was investigated, interpreted and found promising for practical applications. Based on the works of the V. Shestopalov school, the paper is aimed at analyzing properties of oneâ€dimensionally periodic gratings, i.e. at investigating eigenmode spectra and principles of their formation which are determined in particular by the structure of the grating period, and then at analyzing the impact of these spectra on the resonance characteristics. The effects arising in the case of scattering of an Hâ€polarized plane wave by a oneâ€dimensionally periodic metallic bar grating are considered. Specific features of the resonance interaction are treated in terms of the spectral theory of open periodic resonant cavities. A classification is suggested for the spectra of classical and compound gratings. The spectrum of lowerâ€order eigenmodes of the classical grating is investigated in dependence on the grating geometry, and motion of the eigenfrequencies along a multisheeted Riemann surface is analyzed as the grating thickness decreases to zero. It is shown that the limiting points of frequencies of antisymmetric modes correspond to the cutoff points of the higherâ€order Floquet harmonics; the greater the number of eigenmode field variations, the higher order of the harmonic. Eigenfrequency paths on upper sheets and regularities of their crossing the real axis where the wave packet conversion takes place are investigated. The resonance behavior of the grating is described in terms of the unified spectral theory which makes it possible not only to establish the interrelation between different resonance effects but also to determine the source of such a behavior conditioned by excitation of certain eigenmodes.