Analysis and modeling of magnetic-free broadband circulator based on three switched reflection delay lines

Abstract

Magnetic-free broadband circulator structure based on three switched reflection type delay lines with a total electrical length of 180-degree at the switching frequency is investigated. The nonreciprocal transmission property is modeled and simulated, the impedance mismatching property and reconfigurable direction are studied. A prototype magnetic-free circulator circuit is designed and fabricated using coaxial cables and switches driving by switching frequency of 7.94 MHz with tolerance of ±10%. The nonreciprocal scatter parameters are measured in 300kHz ∼ 100 MHz. It shows that the circulator direction can be reconfigured by changing the switching frequency, and the maximum operating bandwidth equals 1.5f_s which is limited by clock feedthrough and spectrum aliasing.

KEYWORDS:

• Nonreciprocity
• circulator
• switched delay line
• magnetic-free

Acknowledgment

This work was supported by the National Natural Science Foundation of China (NSFC) [61771408], [61531016], [61934008], [61401375]; Fundamental Research Funds for the Central Universities [2682014RC24]; Sichuan Province Science and Technology Important Projects [2018GZ0139] [2017GZ0110].

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (NSFC) [grant numbers 61771408, 61531016, 61934008, 61401375]; Fundamental Research Funds for the Central Universities [grant number 2682014RC24]; Sichuan Province Science and Technology Important Projects [grant numbers 2018GZ0139, 2017GZ0110].

Notes on contributors

Dawei Tang

Dawei Tang received the B.E. degree from Southwest Jiaotong University, Chengdu, China in 2020. He is currently studying for Ph.D Degree in Southeast University, focusing on electromagnetic field and microwave technology. His research interests include millimeter wave and terahertz circuit, MMIC design for wireless communications.

Qianyin Xiang

Qianyin Xiang received the Ph. D. degree in the Communication and Information Systems from Southwest Jiaotong University, Chengdu, China, in 2013. He is currently with the Institute of Microelectronics, Southwest Jiaotong University. He has been the principle investigator or researcher in many national research projects supported by the National Natural Science Foundation of China, and Chinese national 863 plan. In recent 5 years, he has published more than 30 research Journal papers on microwave circuits. He is also an active peer reviewer for IEEE Transactions on Microwave Theory and Techniques, IEEE Microwave and Wireless Components Letters, and so on. In 2015, he was awarded as the Young Scientist “Sishi Star” of SWJTU. His current research focuses on reconfigurable/tunable RF circuits and systems, and MMIC design for broadband/high speed communications.

Dengyao Tian

Dengyao Tian received the Ph.D. degree in computer science and technology from Southwest Jiaotong University, Chengdu, China, in 2020. His research interests include RF circuits and antenna systems design for broadband wireless communications.

Mingye Fu

Mingye Fu received the B.E. degree from Southwest Jiaotong University, Chengdu, China in 2017. He is now studying for Ph.D Degree in Southwest Jiaotong University, focusing on microwave technology. His research interests include reconfigurable/tunable RF circuits, MMIC design for broadband/high speed communications.

Xiaoguo Huang

Xiaoguo Huang received the B.Eng. degree in Microelectronics and Ph.D. degree in communication and information system from Southwest Jiaotong University, Chengdu, China, in 2008 and 2015, respectively. He is currently working in Science and Technology on Communication Information Security Control Laboratory, Jiaxing, China. His research interests include Analog/RF/microwave device, circuits and systems.

Quanyuan Feng

Quanyuan Feng received the M.S. degree in Microelectronics and Solid Electronics from the University of Electronic Science and Technology of China, Chengdu, China, in 1991, and the Ph.D. degree in Traffic Information Engineering and Control from Southwest Jiaotong University, Chengdu, China, in 2000. He is the Head of Institute of Microelectronics, Southwest Jiaotong University. He has been honored as the “Excellent Expert” and the “Leader of Science and Technology” of Sichuan Province because of his outstanding contributions. His research interests include RF and microwave circuits, antennas, EM compatibility, and environmental electromagnetics.