Open-loop tunable resonators and filters with constant bandwidth

Athukorala, Lakshman and Budimir, Djuradj (2012) Open-loop tunable resonators and filters with constant bandwidth. IET Microwaves, Antennas & Propagation, 6 (7). pp. 800-806. ISSN 1751-8725

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This study presents a compact novel design for achieving constant bandwidth tunable filters with wide tuning range. A method for linearising the Q-factor against frequency is proposed. A modified coupling structure is introduced to compensate for variations in filtering characteristic across the theoretical 50% tuning range of the filter. Filter design equations are provided for designing Butterworth or Chebyshev filters. An experimental second-order filter is demonstrated with 22.5% pass-band shift with only 3% bandwidth variation and insertion loss better than 3%dB. Furthermore, a third-order tunable bandpass filter with tuning range of 45% and less than 5% bandwidth variation is illustrated through simulation and modelling to show feasibility with higher filter orders. There is very good agreement between the theoretical and experimental results.

Item Type: Article
Subjects: University of Westminster > Science and Technology > Electronics and Computer Science, School of (No longer in use)
Depositing User: Miss Nina Watts
Date Deposited: 24 Aug 2011 17:39
Last Modified: 09 May 2013 10:34

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