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Quasi-Optic Based HE11 Miter Bend at 42 GHz for ECRH Application

By Amit Patel, Pujita Bhatt, Keyur Mahant, Alpesh D. Vala, Jitendra Chaudhari, Hiren Mewada, and Krishnamachari Sathyanarayan
Progress In Electromagnetics Research C, Vol. 108, 37-48, 2021


This paper presents the design and fabrication of HE11 miter bend along with a TM11 to HE11 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 (HE11) mode. The HE11 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 loss (D ≥ λ) is approximately 1.7[Lλ/2a2]3/2 dB. The HE11 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, HE11 miter bend was fabricated along with integrated assembly. The proposed HE11 miter bend with mode converter and corrugated up-taper gives the transmission efficiency of 95.64%.


Amit Patel, Pujita Bhatt, Keyur Mahant, Alpesh D. Vala, Jitendra Chaudhari, Hiren Mewada, and Krishnamachari Sathyanarayan, "Quasi-Optic Based HE11 Miter Bend at 42 GHz for ECRH Application," Progress In Electromagnetics Research C, Vol. 108, 37-48, 2021.


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