Synthesis of X-band trisection bandpass filters using hybrid structures of λ/4 and λ/2 resonators

Muhammad Sufian Anwar, Symeon Nikolaou, Hamza Nawaz*, Muhammad Ali Babar Abbasi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)
132 Downloads (Pure)


This paper presents the design of compact cross-coupled microstrip trisection bandpass filters based on the hybrid structures of quarter-wavelength (λ/4) and half-wavelength (λ/2) resonators. The desired cross-couplings for transmission zeros (TZs) are realized by parallel-coupled transmission-line sections (J-inverter) or coupled via sections (K-inverter) of λ/4 resonators. The main-line couplings, on the other hand, are formed by mixed-coupled λ/4 and λ/2 resonators. To validate the proposed hybrid configurations, two X-band trisection filters with 6.5% and 6.2% fractional bandwidth were designed. The first filter generates a TZ below the passband, while the second one produces a TZ above the passband. Minimum insertion loss of 1.7 dB and 1.5 dB was observed for the two trisection filters, respectively, while the hybrid configurations caused significant size reduction in the overall filter size. Moreover, the first spurious response for the proposed filter topologies was pushed to 3fo, resulting in a wide stopband.

Original languageEnglish
Pages (from-to)1461-1467
JournalMicrowave and Optical Technology Letters
Issue number6
Publication statusPublished - 09 Mar 2019


  • bandpass filter
  • coupling matrix
  • hybrid structure
  • transmission zero
  • trisection

ASJC Scopus subject areas

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


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