Design and Investigation of a Metamaterial Terahertz Broadband Bandpass Filter Based on Dual Metallic Rings

In this paper, we propose a metamaterial terahertz broadband bandpass filter based on dual metallic rings and the filter provides feasible solution for the insertion loss and bandwidth problems of a terahertz filter. A theoretical model of the dual metallic rings metamaterial can be constructed using a frequency-domain finite-difference method. By changing the distance between the two rings, the radii of two rings, and the thickness of the polyimide substrate, we can determine the geometric parameters of a broadband and high-transmittance terahertz filter. The results show that the filter can achieve a passband bandwidth of 0.54 THz at 0.1-1.2 THz and that the terahertz-wave transmittance in the passband can be as high as 93%, effectively improving the overall performance of the terahertz broadband filter.