An approach to suppress the harmonic responses in a dual-mode circular ring resonator bandpass filter is presented. Feed lines with one-sided coupling arms are suitably relocated around the ring resonator to introduce phase interference between two degenerate modes for simultaneously suppressing the second and third harmonics. Three open loop resonators at the rim of the ring are adopted to further suppress the second harmonic. By fabricating on a FR4 glass-epoxy base, this approach is demonstrated to have effectiveness in broadening the filter's rejection band in both simulations and measurements without affecting the fundamental response or increasing the device size.
|Number of pages||4|
|Journal||Journal of the Chinese Institute of Engineers, Transactions of the Chinese Institute of Engineers,Series A/Chung-kuo Kung Ch'eng Hsuch K'an|
|Publication status||Published - 2009 Jan 1|
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