Responses of Voltage and Current Excitations from The Eight-Port Wave Probe’s Perspective for Closed-Loop Circuit Stability Analysis

The bi-directional reflectional coefficients and loop gains from the 8-port wave probe are critical to the understanding of the closed-loop circuit stability, as inaccurate data, being it bidirectional reflection coefficients or loop gains, tend to give wrong system stability prediction even when correct stability criteria are applied. The surveying on data accuracy in the simulation is often neglected by circuit designers; therefore, any improper use of the simulation tool itself can lead to discernable discrepancies between simulation and measurement. It is demonstrated in this paper that the characteristic equations related to external voltage or current excitations can be unambiguously determined by the 8-port wave probe, thus greatly facilitate the task of microwave circuit design.