Compact Dual-band Bandpass Filter Based on Dual-coaxial Resonators
A compact dual-band bandpass filter based on dual-coaxial resonators is proposed in this paper.The dual-coaxial resonator is constructed by embedding one coaxial resonator into the other one,where the conductive post of one coaxial resonator acts as the metallic shielding of the other resonator.Accordingly,a dual-mode resonator is obtained almost without increasing the size as compared to the conventional single-mode coaxial resonator.By investigating the control of resonant frequencies of the dual-coaxial resonator and the control of coupling coefficient between two resonators,separate control of the excitation of two resonant modes and the coupling coefficient between two resonators are achieved.Then,a dual-band bandpass filter with controllable pass-band frequencies and bandwidths is realized.The measured center frequencies are 2.73 GHz and 3.19 GHz,the insertion losses are 0.92 dB and 0.75 dB,and the 3 dB fractional bandwidths are 5.0％and 3.4％.A transmission zero is generated at the fre-quency between the two passbands,achieving a good dual-passband filtering response.
万方数据
维普
