A Triple Band Polarization Insensitive Metamaterial Absorber for Terahertz Applications

A miniaturized unit cell structure design for THz metamaterial absorber for triple band absorption is presented in this paper. Lossy polyimide substrate is used for developing the unit cell structure which consists of two resonators. The miniaturized footprint of the unit cell structure is given by 0.104λ
0
×0.104λ
0
where λ
0
represents the effective wavelength which is being calculated at lowest frequency of absorption. The first resonator of the unit cell structure includes the outer square ring whereas the second resonator consists of S-shaped structures placed at one diagonal position and the other diagonal position is comprised of the same S-shaped structure placed after rotating it leftwards. The unit cell structure provides three absorption bands of 95.868%, 94.691% and 95.434% at 0.347, 0.834 and 0.935 THz respectively. For these frequency ranges the suggested metamaterial absorber possesses various applications in the field of THz imaging, filtering, biological sensing, and optical communications. As the proposed structure has a four-fold symmetry, it reflects similar results for various angles of polarization in TE mode.