Simulation-Based Calibration Verification for (Sub-)Terahertz S -Parameter Measurements

his article presents a cost-effective method for verifying (sub-)terahertz scattering ( S -)parameter measurements using a vector network analyzer (VNA) with frequency extension modules. The approach reduces the need for physical standards with rigorous dimensional characterization by using full-wave electromagnetic (EM) simulation to create a “simulation-driven reference model” with a predictable uncertainty envelope. This method utilizes the known manufacturing tolerances of generic waveguide sections to generate a pass/fail verification bound. Two simple, calculable waveguide devices (a cross-connected line and reduced-aperture sections) are characterized in the WM-570 (330–500 GHz) band. Excellent agreement is achieved between the EM-simulated predictions and VNA-measured S -parameters, with the measurements falling within the calculated uncertainty bounds. This work demonstrates that combining simple hardware with EM simulation is a reliable and low-cost approach for validating S -parameter measurements and calibrations at terahertz frequencies.