Theoretical Investigation on an Array of Dual Tuned Staggered Dipole Apertures by the Method of Moment and Comparison with Experimental Results

A frequency selective surface (FSS) comprising of a two dimensional array of dipole apertures, resonant at two frequencies, within a metallic screen is proposed. A computationally efficient method for analyzing this FSS is used. The formulation is carried out in the spectral domain where the convolution form of the integral equation for the induced current reduces to an algebraic one and the Spectral-Galerkin technique is used to solve the resulting equation. Entiredomain basis function that satisfies the edge condition is introduced to expand the unknown induced current on the complementary structure i.e. an array of printed dipoles. Using Babinet’s principle for complementary screen, the transmitted electric field for the structure of an array of aperture dipoles has been calculated. The theoretical practical data indicate that this structure can be used as a highly selective tuned bandpass filter for GPS and WiMax applications which is very resistant to variations of RF incidence angle of 90° (degree) rotations about any vertical axis, perpendicular to the FSS plane and passing through its centre.