A Novel Ultra-Miniaturized THz Refractive Index-Based Material Sensor

Abstract This paper discusses the design, characterization and analysis of an ultra-miniaturized and highly sensitive metamaterial THz sensor for material sense. A novel spin-shaped resonator integrated with hexagonal is designed as an absorber to perform material sensing operations. The footprint of the proposed sensor is 0.67λeff × 0.67λeff where λeff is the effective wavelength calculated at 7.16 THz. The proposed THz sensor is analyzed based on the absorption characteristics by estimating the sensitivity of the metamaterial sensor. The proposed sensor offers 99.9% absorptivity under free-space conditions. The proposed THz sensor exhibits rotational symmetry and hence it is insensitive to polarization changes. Furthermore, the proposed sensor is angularly stable for oblique incidences up to 60˚. The sensor performance is estimated for different refractive indices of various analytes and the average sensitivity is estimated as 1.37 THz/Refractive Index Unit (RIU). The impact of the thickness of the analyte is analyzed and the average deviation of 59 GHz/µm is reported. Thus, it is concluded that the proposed metamaterial THz sensor is best suitable for different material sensing applications.