Design and Measurement of a Sub-Millimeter-Wave Rectangular TE <sub>1,0</sub> to Circular TE <sub>0,1</sub> Mode Converter
In this article, a sub-millimeter-wave (MMW) rectangular TE1,0 to circular TE0,1 mode converter is designed, fabricated, and tested. The mode conversion is achieved sequentially from rectangular TE1,0 mode to rectangular TE2,0 mode and then to circular TE0,1 mode. To realize the mode conversion from rectangular TE1,0 to rectangular TE2,0, a compact serpentine mode converter design is investigated. Theoretical analysis and numerical simulations demonstrate that the proposed serpentine mode converter demonstrates high mode conversion efficiency across a wide bandwidth. The simulated transmission characteristics reveal that the rectangular TE1,0 to circular TE0,1 mode conversion achieves a 1-dB conversion bandwidth of 96.9 GHz (356.0–452.9 GHz), with high mode purity (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$S_{21}$ </tex-math></inline-formula> for circular TE<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{2,1} \lt -20$ </tex-math></inline-formula> dB) and low reflection coefficients (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$S_{11} \lt -23$ </tex-math></inline-formula> dB). The fabricated mode converter was realized on oxygen-free copper (OFC) using the nano computer numerical control (nano-CNC) milling technology. The cold-test results of the transmission characteristics have an agreement of ±5% over 1-dB conversion bandwidth with the simulations. Within the bandwidth range of 397.2–446.7 GHz, the mode converter exhibits a transmission loss of approximately 5 dB. Compared to a conventional rectangular waveguide (RW), the transmission loss is significantly lower, highlighting the effectiveness of the mode converter. The compact sub-MMW circular TE0,1 mode converter reveals its advantages for low-loss terahertz (THz) waveguides, providing substantial potential for integration into high-frequency systems.
Authors
- Huarong Gong (ORCID: https://orcid.org/0000-0001-6431-0559)
- Zhanliang Wang (ORCID: https://orcid.org/0000-0001-7438-5845)
- Yubin Gong (ORCID: https://orcid.org/0000-0003-3014-1309)
- Jingrui Duan (ORCID: https://orcid.org/0000-0002-1527-7905)
- Yuan Zheng (ORCID: https://orcid.org/0000-0001-9674-1353)
- Zhigang Lu (ORCID: https://orcid.org/0000-0001-8413-1048)
- Mingxu Li (ORCID: https://orcid.org/0000-0002-8325-6997)
- Shaomeng Wang (ORCID: https://orcid.org/0000-0002-2708-9418)
- Peng Gao (ORCID: https://orcid.org/0000-0002-9652-6378)
- Ping Zhang (ORCID: https://orcid.org/0000-0003-1215-3859)
Institutions
- University of Electronic Science and Technology of China (CN)
Publication Details
- Journal
- IEEE Transactions on Microwave Theory and Techniques
- Published
- 2025-03-26
- DOI
- https://doi.org/10.1109/tmtt.2025.3550734
- Citations
- 1
- Primary Topic
- Gyrotron and Vacuum Electronics Research
- Type
- article
- Field-Weighted Citation Impact
- 1.25
Funders
- National Natural Science Foundation of China