A Miniaturized Ultra-thin Wideband Frequency-Selective Surface for EM Protection

In this paper, a novel single-layer wideband ultrathin frequency-selective surface (FSS) is proposed. The designed FSS unit consists of a metal ring with slot, two inner rings attached on both sides of dielectric layer and multi-metal via. The outer ring with slot is responsible for low-frequency resonance and the inner rings work in high-frequency, which brings in two stopbands on the both ends of passband. The multi-metal vias are used to connect the top and bottom patches and enhance the effective inductance, which makes a significant contribute to miniaturization. Finally, the FSS unit with 0.15$\lambda(\lambda=10$GHz) in size and 0.027$\lambda$ in thickness can realize a large −3dB bandpass from 10 GHz to 18 GHz, and has sharp roll-offs rates at the edges of the passband.