High power test of wideband polarizer for electron cyclotron current driving system in JT-60SA

A wideband polarizer consisting of a polarization twister and a circular polarizers have been developed for the Electron Cyclotron Current Drive system in JT-60SA at the frequencies of 110 GHz and 138 GHz. Ohmic loss of the polarization twister has been evaluated with high power test of 0.3 MW, 10 s at 110 GHz and 138 GHz. The Ohmic loss of the polarization twister made by machining process is 0.20% ∼ 0.57%. Moreover, the wideband polarization twister was tested up to 0.9 MW for 20 s at 110 GHz and 138 GHz.