Frequency Tunable Non-Reciprocal Bandpass Filter Using Time-Modulated Microstrip ¿<inf>g</inf>/2 Resonators

Journal ar
IEEE Transactions on Circuits and Systems II: Express Briefs
  • Volumen: 68
  • Número: 2
  • Fecha: 01 February 2021
  • Páginas: 667-671
  • ISSN: 15583791 15497747
  • Source Type: Journal
  • DOI: 10.1109/TCSII.2020.3014499
  • Document Type: Article
  • Publisher: Institute of Electrical and Electronics Engineers Inc.
© 2004-2012 IEEE.This brief presents a novel frequency reconfigurable microstrip non-reciprocal bandpass filter based on time-modulated microstrip \lambda _{g}/2 resonators. The modulation is achieved by loading both ends of the \lambda _{g}/2 transmission line resonators with time-modulated capacitors. The modulation voltage source is connected at the center of the resonator, where there is a natural voltage null, and a single inductor is used to further enhance the biasing isolation. The wideband nature of this isolation scheme enables the tuning of the devices over a wide frequency range. With more than 30-dB RF to modulation isolation, the proposed resonator structure also enables low insertion loss by eliminating RF signal leakage to the modulation ports. A 3-pole bandpass filter example is simulated and measured, showing a minimal insertion loss of 3.9dB, a 20-dB isolation bandwidth of 42MHz at 1.0GHz, and frequency tuning range of 885-1031MHz.

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