Terahertz Metamaterial Absorber and Equivalent Circuit Model for Refractive Index Sensing.

As a kind of important functional device, terahertz metamaterial absorbers (TMA) have been focused on by many researchers for their capacity to absorb electromagnetic waves and wide application fields. In this work, we designed a terahertz metamaterial absorber with narrow-band absorption for refractive index sensing, which consisted of a circular metal ring resonator and a square metal ring resonator. The simulation results show that the absorptivity of the proposed TMA reached over 68.