Tripole type wideband bandpass frequency selective surface for X‐band applications

Abstract

The study presents a novel single dielectric layer wideband bandpass frequency selective surface (FSS) topology. The structure is designed using a kind of the tripole type FSS which has been analysed for its behaviour. Next, the operating bandwidth has been increased by using the meander lines in the middle of the unit-cell. The proposed FSS structure covers the X-band (45.03% fractional bandwidth) of the electromagnetic (EM) spectrum with a −3 dB transmission bandwidth. Its −1 dB bandwidth extends from 7.93 to 11.93 GHz. The wide operating bandwidth with a single dielectric layered structure makes it suitable for the hybrid radome applications. For the normally incident EM wave, adjacent to the lower and upper cut-off frequencies, the structure offers better than 18 dB attenuation which increases the out of the band rejection. Finally, the proposed structure is fabricated and experimentally verified for the dual polarisation and angle stability up to 45°. Eventually, to prove the novelty in terms of the operating bandwidth and the fabrication simplicity, an exhaustive state-of-the-art comparison is also presented.