Design and Experimental Validation of Linear to Circular Polarization Converter for Point to Point THz Communication

This letter presents a compact, low profile singe substrate transmissive linear-to-circular polarization (LCP) converter designed and experimentally validated for point-to-point THz communication bands. The proposed LCP converter consists of an H-shaped gold metallic pattern deposited on both sides of a 100µm-thick fused silica substrate. The LCP converter operates within the 0.225-0.307 THz frequency band, achieving a simulated 3-dB axial ratio bandwidth of 30.8% in simulation. Owing to its wide axial ratio bandwidth, the proposed design is a promising candidate for point-to-point THz communication applications. The performance of the proposed converter is verified through surface current distribution explaining the occurrence of Hyugen’s response and equivalent circuit model. The proposed converter exhibits a measured 3-dB axial-ratio bandwidth of 27.8% in the frequency band 0.229–0.303THz. The simple geometry and the single substrate implementation with a thin profile and wide 3-dB axial ratio bandwidth of the proposed design makes it suitable for practical deployment scenarios.