A Broadband Terahertz Circular Polarization Selective Surface

This paper introduces a novel wideband circular polarization selective surface (CPSS) design operating at terahertz (THz) frequencies. The proposed right-hand CPSS can reflect the right-hand circularly polarized (RHCP) electromagnetic waves while transmitting the left-hand circularly polarized (LCHP) ones. The CPSS consists of three metallic grating layers separated by SU8 substrates without any vias interconnection. The proposed structure combines two linear-to-circular polarization converters sharing the same linear grating polarizer, substantially reducing the required number of metallic layers. Measured results show that the proposed CPSS presents a wide bandwidth of 57% with a transmission CP discrimination of more than 15 dB from 0.6 THz to 1.08 THz.