This paper presents the design and implementation of dual-band filters. The proposed method works well for dual-band filters with asymmetric dual-passband, high selectivity, and pre-assigned in-band return loss levels (e.g. equal or un-equal at two frequency bands). To verify the design concept, a prototype dual-band filter using combline coaxial cavity-type resonators was designed, fabricated and tested. Good agreement has been achieved among the theoretical synthesis results, simulation results and measurement results.
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