Wideband and Multi-band Frequency Selective Surfaces for Microwave Shielding

Monolayer band-reject frequency selective surfaces (FSS) based on curved coupled microstrip line (CCML) resonators are proposed. Each unit cell comprises a single- or multi-loop CCML resonator, featuring single-wideband or multi-band resonance, respectively. Design guidelines for achieving various responses are demonstrated and it is shown there is a great flexibility attaining desired frequency responses versus structural parameters. For instance, it is shown that the entire microwave X-band may be rejected, using a simple single-loop structure. The FSS is particularly useful for protecting buildings against parasitic microwave signals. A visual transparency factor for the FSS, when regular glass is used as substrate, is defined and calculated to be between 55% to 88% for various frequency responses