Quasioptical transmission lines for ECRH at TJ-II stellarator

Two mirror lines have been used to transmit the microwave power from the po werful microwave generators to the TJ-II plasmas. Both lines have been test ed at nominal power level and they are in operation now. This paper deals w ith the final design of the transmission lines and their testing. Before st arting operation at high power level, measurements of the wave beam paramet ers silt low power level were performed. Two horn antennas were designed to simulate the gyrotron output. The results are presented in this paper. A c omputer code based on Huygens diffraction theory was developed to simulate the propagation of the beam along the mirror lines. A comparison of the the oretical and the experimental results is also shown here.