High-Selectivity Bandpass Filter Based on Two Merged Ring Resonators

Xiao Yu Weng, Kai Da Xu, Ying Jiang Guo, An Xue Zhang, Qiang Chen

Research output: Contribution to journalArticlepeer-review


A high-selectivity bandpass filter (BPF) based on two merged ring resonators is presented in this paper. The structure of this proposed BPF can be seen as the two one-wavelength ring resonators merged each other by sharing the common λ/2 microstrip line. Due to symmetric structure, it can be analyzed by even- and odd-mode method and the locations of six transmission zeros are calculated using input impedance deductions. For further demonstration, a BPF example centered at 2 GHz is fabricated with high frequency selectivity. The measured 3-dB fractional bandwidth is 11% (1.89–2.11 GHz) and insertion loss is less than 2 dB in the passband. Good agreement between simulation and measurement verifies the feasibility of the design method.

Original languageEnglish
Pages (from-to)504-509
Number of pages6
Issue number3
Publication statusPublished - 2021 Sept


  • Bandpass filter
  • coupled-line structures
  • high selectivity
  • transmission zeros

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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