Investigations on a Fluidic THz True Time Delay Based on a Dielectric Slot Waveguide

This paper presents a broadband fluidic THz True Time Delay Line (TTDL) based on Dielectric Waveguides (DWGs) fabricated using High Impact Polystyrene (HIPS) in an additive 3D-printing process. The proposed design utilizes an asymmetrical mode converter, generating an air-guided field between two dielectric slabs. The structure was optimized for operation between 140 and 220GHz through full-wave simulations. The relative time delay is adjusted by filling varying amounts of fluid into the converter using a micropipette. Measurements were conducted with a Vector Network Analyzer (VNA) equipped with G-band extension modules. The TTDL demonstrates a bandwidth exceeding 120GHz with low insertion loss.