Measurement of fully symmetric four-port device using two-port network analyzer

Focusing on characterizing fully symmetric four-port devices using a two-port vector network analyzer (VNA), the authors formulate a new method of measurement in this paper. The device under test (DUT), is embedded in two probe pads and two auxiliary terminations for one to perform on-board measurement using two ground-signal-ground (GSG) probes and a two-port VNA. The DUT is a 30 GHz substrate integrated waveguide (SIW) Riblet short-slot hybrid with microstrip-to-waveguide transitions, and is fabricated on Rogers RO4003 ^reg substrate with 8 mil thickness. By taking advantage of the thru-reflection-line (TRL) calibration technique and the new method, the four-port scattering matrix (S-matrix) of DUT is reconstructed.