Broadband THz Absorber for Large Inclination Angle TE and TM Waves

Abstract

Terahertz (THz) electromagnetic wave absorbers are finding new applications both in military and civilian sectors. This is the reason why constant efforts have been made worldwide to enhance the working performance of these absorbers. One downside of the available absorbers is their response to Transverse Electric (TE) and Transverse Magnetic (TM) waves at different frequency bands. Specific strategic applications require response of an absorber in same frequency band for TE and TM electromagnetic waves, for large inclination and polarization angle of the incoming signal. In this work, we present a metasurface based THz absorber with improved functionality. The fractional bandwidth is 91.64% w.r.t the center frequency of 1.97 THz, that shows an absorptivity of more than 90%. Due to the fourfold symmetry, the absorber is polarization insensitive. It shows more than 80% absorptivity for incoming wave inclinations upto $60^{\circ }$. The thickness of the absorber is $\sim$ $\lambda$/11. The good point is that the absorber shows all these improved performance for both TE and TM incoming signals in the same frequency range. Overall, the designed absorber is a much improved version of its peers available in the literature.

Keywords

• Graphene
• metasurface
• absorber