Bragg resonances in a doubly periodic planar waveguide

Abstract

The dispersion relation for a doubly periodic electromagnetic waveguide is determined by means of the null-field and modal approaches. The waveguide walls are assumed to be perfectly conducting and to have the form of corrugated parallel plates. Bragg resonances appear in the form of stopbands or cross-over resonances. The field inside the waveguide is obtained by means of modal theory. Numerical problems that emanate from mode degeneracy and large matrix sizes are dealt with by means of the Muller algorithm and singular value decomposition. The computed Poynting vector and the group velocity are discussed.