Corrugated horn antenna for low-power testing of the quasioptical transmission lines at TJ-II stellerator

This paper presents the design and characterisation of a millimetre-wave corrugated horn antenna to perform low power measurements of the main parameters of the quasioptical transmission lines of the Electron Cyclotron Resonance Heating (ECRH) at TJ-II stellerator experiment working in Madrid (E). The antenna generates a practically pure Gaussian Beam at 53.2 GHz that simulates the stellerator gyrotron output beam. Simulations of the designed corrugated horn, by using a specially developed computer code, are presented. The far field radiation pattern of the constructed prototype was measured at the ESTEC Compact Antenna Test Range (CATR). The measurement results are in excellent agreement with those obtained from simulations.