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Asian Journal of Physics Vol. 33, Nos 9 & 10 (2024) 563-573

Conversion of dominant rectangular-waveguide-mode to azimuthally symmetric circular-waveguide-mode in sub-terahertz frequency band

Vishal Kesari1, Sarah Farheen2 and Swappnal Panigrahi2
1Microwave Tube Research and Development Centre, Defence Research and Development Organisation, Bangalore-560 100, India
2Electronics and Communication Engineering, People’s Education Society Institute of Technology-Bangalore South Campus, Bangalore-560 100, India
This paper is dedicated to Dr Shrinivas Joshi

A mode-converter was simulated to convert the dominant TE1,0 rectangular-waveguide-mode to azimuthally symmetric TE0,1 circular-waveguide-mode in the sub-terahertz frequency band using High Frequency Structure Simulator (HFSS). The proposed simulation was centered around 100 GHz. In order to achieve the targeted mode conversion, the dominant TE1,0 rectangular-waveguide-mode was first converted to the rectangular-waveguide-mode TE2,0, and further the TE2,0 rectangular-waveguide-mode is converted into azimuthally symmetric TE0,1 circular-waveguide-mode. The conversion of rectangular TE2,0 to circular TE0,1 mode occurred in three steps. These three steps perform rectangular to square conversion, square to elliptical conversion, and elliptical to circular conversion, respectively. The coupling-loss was calculated for each step of mode transition and also for the full mode-converter to estimate the coupling of energy from the mode at input port to the mode at output port. The least possible value of coupling-loss will infer to the highest possible coupling of energy. Initially, the geometrical dimensions for each step of the mode transition are optimized independently for the least possible coupling-loss, and further all the sections were cascaded and the fine-tuning in optimization was done for the full mode-converter. The coupling-loss of the proposed mode-converter was found to be better than 1 dB over 88-111 GHz, and the achieved bandwidth was 19.7 GHz at 0.5 dB coupling-loss. © Anita Publications. All rights reserved. doi:10.54955/AJP.33.9-10.2024.563-573;
Keywords: Electromagnetic mode, Mode converter, Mode transducer, Sub-THz mode converter.

Peer Review Information
Method: Single- anonymous; Screened for Plagiarism? Yes
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