Design Broadband-Pass Frequency Selective Surface Utilizing a Thin Substrate Based on LC Couplings

In this letter, we propose a frequency selective surface (FSS) made of three metal layers cascade by two layers substrates. An equivalent circuit model for the operating principle of FSS was proposed. On the basis of the transmission lines theory, the approximation formulas of the inductance and capacitance were provided. In order to the optimal parameters of broadband performance, the impact of geometrical parameters on LC coupling is discussed by the analysis of simulation calculated. A prototype was fabricated and a measured. A good agreement between the simulated and measured transmission coefficients is obtained. Furthermore, The FSS under the oblique incidence and different polarizations also present stabilized wideband band-pass performances.