Ultra-thin polarization-insensitive metamaterial triple bandpass filter with high quality-factors

An ultra-thin metamaterial triple bandpass filter with high quality-factors is presented. This proposed structure consists of a periodic array of three concentric circle ring resonators at the top layer and a metallic mesh at the bottom layer, which are separated by a thin dielectric substrate. The investigations on the distribution of the electromagnetic field and surface current are made for explaining the filtering mechanism. The structure is also demonstrated to be flexibly and independently tunable of the pass-band resonance frequencies. Moreover, this simple structure with ultra-thin thickness is also a symmetric design which is insensitive to the polarization and incident angles. Experimental measurement of the manufactured sample show good agreement with the numerical simulations. Therefore, such a metamaterial triple bandpass filter is of great importance in some practical applications.