A Rigorous Equivalent Network for Linearly Polarized THz Absorbers

Linearly polarized electromagnetic absorbers are often used in THz space science as means of power detection. In this paper, we present a rigorous and analytical equivalent network suitable for the analysis of these structures. The model includes, on one hand, the vectorial representation of the general propagation and scattering of the dominant electromagnetic waves and, on the other hand, details of the absorber geometry. Unlike existing models for frequency selective surfaces (FSS), the present network highlights the full interaction between TE and TM modes and the current in the strips that couples them. The network is elegant, simple and accurate, providing the explicit description of the dominant physical mechanism involved. The tool derived from the network is used for designing several THz absorber based detectors showing broadband absorption efficiencies. The network is validated with full wave simulations.