Measurement of antenna S-parameters and their application to the analysis of resonance loop system for the ICRF heating of fusion plasmas

It is important to accurately measure the ICRF antenna parameters for the estimation of RF power transmission to KSTAR fusion plasmas. Due to the complexity of a 4-loop antenna with mutual couplings, it is not easy to measure those parameters directly. In this presentation, a method to determine those antenna parameters more precisely by applying measured S-parameters to a coupled transmission line model is introduced, and the characteristics of the resonance loop of the KSTAR ICRF system for the heating of KSTAR fusion plasmas are analyzed by using the determined parameters.