Design and characterization of wideband high-efficiency unit cells for frequency selective surfaces in 10GHz-band

This paper investigates two new unit cells featuring wideband low loss characteristics for frequency selective surfaces (FSS) in X-band applications. The FSS is realized as a uniform array of the proposed unit cells. Each unit cell is a three layer structure consisting of two back-to-back microstrip patch antennas and a non-radiating resonator in the common ground plane. These proposed FSS elements have been designed and optimized using the finite element method simulation. A waveguide measurement system (WGMS) has been used to characterize the first cell (symmetric) and a free space Gaussian optics measurement system (GOMS) has been used to characterize the second cell (asymmetric). An excellent agreement has been obtained between the simulation and measurement in terms of impedance matching (S11<;-10 dB, 7.3% and 8.5% around 10 GHz for the two cells, respectively) and insertion loss (<; 0.4 dB at 10 GHz).