3D‐tapered resonators for FSSs with incident angle independence

Abstract

A three‐dimensional (3D) frequency selective surface (FSS) with a response that is independent of incident angle is presented in this study. The proposed FSS is a periodic array of 3D hollow‐tapered resonators. The proposed 3D FSS has reduced sensitivity to the angle of incidence of the electromagnetic wave compared with other 2D and 3D FSSs as a result of tapered structure. The transverse electric (TE) and transverse magnetic (TM) incident angle independences are obtained by tapering the width of a cylinder with a square cross‐section from the upper opening to the lower opening. Impressive frequency stability and transmission characteristics have been achieved up to 80° for both TE and TM incidence angles. The principles of operation along with guidelines for the design of the proposed FSS structures are presented in this study. A prototype of the proposed 3D‐tapered FSS is also fabricated and tested using a free‐space measurement system to verify performance.