Extended passband bandstop filter cascade with continuous 0.85-6.6-GHz coverage

Eric J. Naglich, Juseop Lee, Dimitrios Peroulis, William J. Chappell

Research output: Contribution to journalArticlepeer-review

42 Citations (Scopus)


This paper presents a cascade of tunable bandstop filters with a wide spurious-free upper passband, which is completely spanned by the tuning range of the notch responses. A collection of resonators is shown to be able to provide bandstop filter responses over a 7.8 to 1 tuning range. By using spurious-free upper passband aperture-coupled cavity bandstop filters, multiple resonators, each with octave tuning, can cover a multioctave frequency range in a cascade. It is shown that the upper passband of this type of filter is limited by the reactance of the coupling apertures, which produce an unwanted in-band resonance unless designed properly. The details of this design process are explained and used to design a six-resonator bandstop filter cascade that is able to provide a bandstop filter response with up to 55 dB attenuation over the continuous band of 0.85-6.6 GHz. Through dynamic allocation of the cascade circuit's transmission zeros, one-, two-, three-, and four-pole bandstop filter responses of variable bandwidth can be realized over different frequency ranges, offering numerous bandwidth-attenuation level tradeoff combinations.

Original languageEnglish
Article number6095352
Pages (from-to)21-30
Number of pages10
JournalIEEE Transactions on Microwave Theory and Techniques
Issue number1
Publication statusPublished - 2012 Jan
Externally publishedYes


  • Filters
  • microwave filters
  • passive filters
  • tunable filters
  • tunable resonators

ASJC Scopus subject areas

  • Radiation
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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