Dual-band bandpass filter using helical resonators

Ruwan Gajaweera, Yahui Wu, Jeremy Kenneth Arthur Everard

Research output: Chapter in Book/Report/Conference proceedingConference contribution


This paper demonstrates non-uniform pitch helical resonators for realization of dual-band bandpass filters. By modifying the pitch and coil diameter of conventional uniform pitch helical resonators, the desired dual-band frequencies can be obtained. The external coupling and inter-resonator coupling structure are also illustrated. A non-uniform pitch helical resonator was designed and fabricated with unloaded quality-factor (>900) for both passbands. A 2nd order Butterworth filter that has passbands at 840 MHz and 2590 MHz has been designed. The simulation results show that the filter has a good selectivity with 6% and 4.3% fractional bandwidth at the passbands, respectively. The good power handling capability also suggests that the filter is applicable for microcell/picocell LTE base stations.
Original languageEnglish
Title of host publication 2016 46th European Microwave Conference (EuMC)
Number of pages4
ISBN (Electronic)9782874870439
Publication statusPublished - 19 Jan 2017

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