S parameters of a single coupler extracted from the whole SWS system

Abstract

In this paper, the S parameters of a single coupler are extracted from the whole slow-wave-structure (SWS) system. The basic theory is derived. The simulation model is built up based on the helix SWS in the code CST Microwave Studio. The whole S parameters of the system are simulated. The parameters of a single coupler are obtained from the whole parameters based on the derived theory. The results can be used to evaluate the match characteristics of a single coupler to the helix SWS system.