Ultra-Wideband Quasi-Circulator Implemented by Cascading Distributed Balun with Phase Cancelation Technique

Si Da Tang, Chih Min Lin, Shih Han Hung, Kai Wen Cheng, Yeong Her Wang

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


This paper presents the implementation of a broadband quasi-circulator through a cascading distributed balun using a 90-nm CMOS process. The isolation, , of the proposed three-port quasi-circulator can be acquired through the phase cancelation technique, by connecting an additional distributed amplifier in parallel between ports 1 and 3. The thorough analysis based on an eight-port chain matrix and scattering matrix is presented for refining the circuit parameters in the initial design. Measured results show that the proposed quasi-circulator attains a broad operation bandwidth ranging from 10 to 67 GHz. Moreover, the quasi-circulator also has good insertion gain of 0.5 to 4.8 dB, as well as isolation, which is better than 23 dB. Consequently, the proposed quasi-circulator delivers wide bandwidth performance, good port-to-port isolations, good insertion gain, and high linearity based on the cascading distributed balun with phase cancelation technique.

Original languageEnglish
Article number7490395
Pages (from-to)2104-2112
Number of pages9
JournalIEEE Transactions on Microwave Theory and Techniques
Issue number7
Publication statusPublished - 2016 Jul

All Science Journal Classification (ASJC) codes

  • Radiation
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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