Ultra-Thin Single Layered FSS with Closely Spaced Quad Band Response and Higher Angular Stability

This paper proposes a novel single layered frequency selective surface (FSS) design with high angular stability and closely spaced quad band response. The unit cell of the proposed 3-D FSS design is imprinted using 0.25 mm FR-4 substrate as the base for the patch elements. The design thus proposed consists of concentric "sun like" structures encompassed inside a rectangular frame. The unit cell size is very compact having dimensions 0.028λ*0.028λ*0.003λ. The novel proposed structure resonates at frequencies. The four adjacent pass bands obtained at 4.1 GHz, 5 GHz, 6.1 GHz, and 8 GHz are separated by sharp transmission zeroes leading to desired rejection response on both sides. The novel proposed structure finds application for upcoming 5G technology which falls in the Sub Gigahertz range along with various other C band applications.