Experimental Realization of Conformal Bandpass FSS for Radome Applications

This letter presents a dual-polarized, conformal bandpass frequency selective surface (FSS) designed and experimentally tested to provide a stable transmission window in the X-band under both concave and convex bending conditions. The bandpass FSS comprises of a square shaped slot etched on 0.254 mm thick FR-4 substrate with single-sided copper-cladding. The proposed bandpass layer operates at 10.1 GHz, and its transmission characteristics are further explained through an equivalent circuit model. The FSS maintains a stable angular response for incident angles up to 70∘ and performs effectively under bending up to 180∘. Additionally, when integrated with a patch antenna, the cylindrically bent conformal FSS introduces a minimal distortion to its far-field characteristics. Due to these attributes the proposed bandpass FSS can be used for conformal and flexible electromagnetic applications.