A novel fast roll-off bandpass frequency selective surface for stealth applications

A novel frequency selective surface (FSS)-based spatial bandpass filter for TM-polarized waves is reported. The unit cell of the proposed FSS consists of a dielectric substrate with two conducting layers on opposite sides. One magnetic resonator is placed on the top conducting layer, while two pairs of electric resonators are positioned on the bottom conducting layer to provide a fast roll-off bandpass characteristic. The simulated values of the −3 dB to −10 dB roll-off factor (RF) for the proposed structure are 140 and 280 dB/GHz on the lower and upper sides of its passband, respectively. To validate the simulation results of the proposed structure, a prototype of the FSS-based filter was fabricated and tested experimentally. Furthermore, the present simulation results are benchmarked with the band-pass FSSs reported in the literature, demonstrating an advantage of the proposed filter over the filters mentioned in previous works.