High-Q and FOM Dual-Band Polarization Dependent Ultra-Narrowband Terahertz Metamaterial Sensor

Polarization-dependent dual-band THz metamaterial using a modified Trishul structure is proposed in this paper. The absorber has three layers namely, a conducting ground plane, a dielectric substrate, and a structure top metallic patch. The top and bottom metallic is made up of gold material and the dielectric substrate is polyimide. The characteristics are obtained using the finite element method. The structure has obtained two resonant peaks at 0.78 THz(f1) and 1.65 THz(f2) for the X-polarized wave and at 0.81 THz(f3) and 1.53 THz(f4) for the Y-polarized wave respectively. The simulation result reveals that the absorber has obtained ultra-narrow band absorption with a full width half maximum(FWHM) of 4.8 GHz, 10 GHz, 5 GHz, and 10 GHz for f1, f2, f3, and f4 respectively. In addition, the underlying physical mechanism of the multi-band characteristics is analyzed using electric field and surface current distributions. The proposed absorber design has importance in the emerging THz system for polarization imaging and sensing applications. Also, flexible metamaterials could be useful for soft robotics applications also.