Stepped impedance hairpin design of a tunable bandpass filter with harmonic suppression

Yu Wei Chen, Min-Hua Ho

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


Stepped impedance hairpin resonators (SIHRs) with harmonic suppression and capability of frequency tuning are incorporated into a bandpass filter design. A tapped-in U-shaped feed structure is introduced to suppress harmonics and to reduce the passband insertion losses. The passband flexibility is accomplished by using a pair of tuning varactors. A simple method to implant a zero in the frequency response is also studied herein to further deepen the passband skirt. A 176% (4.32 GHz) stopband bandwidth is observed under more than 20-dB band rejection. A measured minimum insertion loss of 1.19 dB is observed for the circuit with absence of the tuning varactors. Using the varactors, this filter has achieved a 22% frequency tuning range with all the insertion losses less than 5 dB.

Original languageEnglish
Pages (from-to)697-701
Number of pages5
JournalMicrowave and Optical Technology Letters
Issue number4
Publication statusPublished - 2006 Apr 1

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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