Angular Stability Enhancement Using Phase Compensation Method for Frequency Selective Surface Design

Abstract

This study introduces a novel phase compensation-based, asymmetric frequency selective surface (FSS). Aimed at enhancing angular stability, the phase compensation method utilizes the reflected phase gradient changes generated by two FSSs at large grazing angles. The ultimate improvement in angular stability comes from unit amalgamation to achieve phase complementarity, effectively dealing with the phase shift of incident waves caused by large grazing angles. Based on this principle, the asymmetric FSS structure is built with 3 components: a Minkowski fractal cell, a bent-line square-loop cell, and a thin square-loop parasitic cell. Simulation results show the structure demonstrates a 0 relative shift of resonant frequency within an incidence range of 0-80° under transverse electric (TE) polarization. However, it exhibits a maximum relative shift of 5.12% in resonant frequency at an 80° incidence under transverse magnetic (TM) polarization. Compared with $E_1$ and $E_2$ units, this structure significantly reduces frequency deviation—by 100% at 80° incidence under TE polarization and by 80.12% and 83.26% compared with $E_1$ and $E_2$ units under TM polarization. Finally, the proposed FSS model was fabricated and processed, with measured data basically aligning with the simulated results.