QUASI-OPTIC BASED HE₁₁ MITER BEND AT 42 GHZ FOR ECRH APPLICATION

Abstract

This paper presents the design and fabrication of HE 11 miter bend along with a TM 11 to HE 11 mode converter and corrugated up-taper, which are the integral parts of a transmission line system (TLS) that carries 200 kW microwave power at 42 GHz from Gyrotron to plasma or calorimetric dummy load. It has a hybrid (HE 11 ) mode. The HE 11 mode transmission loss in miter bend is derived using mode-matching techniques and gap loss theory. The gap length (L) in a waveguide of diameter (D = 2a) at a wavelength (λ) for the predicted loss3 2 dB. The HE 11 miter bend design incorporates a demountable cooling assembly with a flat mirror. The design and optimization of the proposed miter bend were carried out using CST-microwave studio software. Finally, HE 11 miter bend was fabricated along with integrated assembly. The proposed HE 11 miter bend with mode converter and corrugated up-taper gives the transmission efficiency of 95.64%.