Active three-way circulator using transistor feedback network

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal

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Original languageEnglish
Article number7902145
Pages (from-to)476-478
Journal / PublicationIEEE Microwave and Wireless Components Letters
Issue number5
Publication statusPublished - May 2017


This letter presents an active three-way circulator with both theoretical analyzes and experimental verifications. The conventional active circulators have their limitations on power handling and noise figure (NF), however, this proposed
structure maintains both performances, which is formed by three 2-port transistor feedback networks (TFNs). This TFN is formed by an FET together with a feedback inductor. Experimental results show that this circulator achieves the isolation more than 35 dB, the insertion of around 2 dB, and the return losses
better than 10 dB at each port at 1.8 GHz. The output power is linearly proportional to the power operation and the NF is around 5 dB. This compact structure, therefore, is suitable for use in the transmit/receive front end with a sufficient isolation, power handling, and NF for time division duplex operation.

Research Area(s)

  • Active circulators, Monolithic microwave integrated circuit, Noise figure (NF), Quasi-circulators