Polarisation-insensitive and broadband band-stop metamaterial filter for THz waves

Abstract

This paper describes the design and analysis of the tri-band metamaterial band-stop filter for terahertz applications. The design consists of a structured gold metallic patch over a flexible polyimide substrate. The thicknesses of the substrate and the metallic patch are 125 and 1 $\mu \hbox {m}$, respectively. The simulation results reveal that the designed structure resonates at three frequencies: $f_{1}=0.6$ THz, $f_{2}=1.4$ THz and $f_{3}=2.4$ THz. The proposed structure has polarisation-insensitive and angle-resolved transmission characteristics. The structure has 200 GHz and 800 GHz bandwidths at $f_{1}$ and $f_{2}$. This proves that the proposed design will be useful for broadband terahertz applications. The multiband resonances have been confirmed and analysed using the field and surface current distributions. These multiband resonances were due to the combination of electric dipolar, quad polar and magnetic dipolar resonance behaviour of the patterned metallic structure.