Distortion mechanisms in varactor diode-tuned microwave filters

BE Carey-Smith, PA Warr

Research output: Contribution to journalArticle (Academic Journal)peer-review

13 Citations (Scopus)
397 Downloads (Pure)


This paper examines the broadband distortion behavior in flexible filters employing varactor-diode tuning elements. Series- and parallel-resonant varactor-loaded transmission-lines, both commonly used in bandpass and bandstop microwave filters, are analyzed. Nonlinear Volterra-series analysis is employed to determine the second- and third-order distortion ratios dependent on the frequencies of the incident signals. It is shown that in a bandpass filter (employing parallel tuned resonators), maximum distortion occurs in the passband, while in a bandstop filter (employing series tuned resonators), minimum distortion occurs at the minimum-loss passband. The analysis is verified by practical measurement of filters employing the two modes of resonators
Translated title of the contributionDistortion mechanisms in varactor diode-tuned microwave filters
Original languageEnglish
Pages (from-to)3492 - 3500
Number of pages9
JournalIEEE Transactions on Microwave Theory and Techniques
Issue number9
Publication statusPublished - Sep 2006

Bibliographical note

Publisher: IEEE
Rose publication type: Journal article

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  • microwave filters
  • distortion
  • tunable filters


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