Dualband frequency selective surface with double-four-legged loaded slots elements

A design is presented for a dualband frequency selective surface (FSS) with double-four-legged loaded slots elements(DFLLSs). The four-legged loaded slots elements are first applied to design a dualband spatial bandpass filter. This type of FSS is constructed using two periodically different size four-legged loaded elements that have geometrical self similarity. And two dielectric slabs are added to each side of the single slotted surface. Its frequency performance is obtained by using numerical simulation software HFSS based on finite-element method (FEM). The simulated results show the good stability of the resonant frequency and bandwidth at different polarisation states and various incident angles.