Dual‐band band pass filter using stub‐loaded open‐loop resonators with wide controllable bandwidths |
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Authors: | Yinxia Zhu Bo Liu Jian Cheng Jun Jin Beijiang Zhang Xiang Tian |
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Affiliation: | Institute of Communication Engineering, PLA University of Science and Technology, , Nanjing, 210007 China |
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Abstract: | Two dual‐band band pass filters (BPF) using stub‐loaded open‐loop (SLOL) resonator are presented in this article. A novel coupling tuning method by changing the relative coupling position of the resonators is proposed to control the bandwidth of each passband in a wide range. Transmission zeros are created to improve the selectivity by source‐load coupling. Because of the large ratio of two bandwidths, a novel dual‐band matching method is proposed to match the different load impedances at two passband frequencies to the same source impedance. Hence, relax the fabrication requirement of gap. The proposed dual‐band band pass filter is designed and fabricated. The measured 3 dB fractional bandwidths (FBWs) of two 2.45/5.25 GHz dual‐band BPFs are 6.5%/14.5% and 9.8%/5.5%, respectively. The results are in good agreement with the simulation. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:367–374, 2014. |
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Keywords: | band pass filter controllable bandwidths dual‐band transformer stub‐loaded open‐loop resonators source‐load coupling |
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