A COMPARATIVE-STUDY OF ANGULAR SCATTERING CHARACTERISTICS OF A CLASS OF NONPLANAR FREQUENCY-SELECTIVE SURFACES

In this paper we use the Method of Moments to study the transmission p roperties of a number of frequency selective surfaces (FSS) with 3D el ements, such as the tri-dipole, the dipole-loop, the tri-loop, and the bi-loop. The frequency responses of these 3D-FSSs and those of the pl anar frequency selective surfaces with 2D elements, such as the loop a nd the window, are presented graphically for normally as well as obliq uely incident plane wave illuminations. In general, the 3D-FSSs degrad e the wide-angle performance of the original planar loop structure. Th e nonplanar elements do offer the flexibility of widening the bandwidt h of the frequency response and introducing multi-band capabilities wh en the plane wave is incident from a wide angle. However, insofar as t he wide-angle response is concerned, the planar loop is still the most robust of all the structures investigated in this study.