A bandpass filter with adjustable bandwidth and predictable transmission zeros |
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Authors: | Li Zhu Vijay Devabhaktuni Chunyan Wang Ming Yu |
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Affiliation: | 1. ECE Department, Concordia University, Montreal, H3G 1M8, Canada;2. EECS Department, MS 308, University of Toledo, Toledo, OH 43606;3. COM DEV Ltd., Cambridge, N1R 7H6, Canada |
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Abstract: | In this article, a microstrip bandpass filter with an adjustable bandwidth and predictable transmission zeros is proposed. The proposed filter is implemented by combining two hairpin edge‐coupled resonators with interdigital capacitors. Compared to typical edge‐coupled filters, the proposed filter provides a wider bandwidth resulting from a higher coupling strength between its resonators. To further increase the coupling and consequently the bandwidth, a pair of etched slots in the ground plane is used. By adjusting the geometrical parameters of the interdigital capacitors and etched slots, the bandwidth can be easily adjusted. The filter features two transmission zeros, which are determined by means of the semi‐analytical model developed as part of this work. Furthermore, the proposed filters can be cascaded to obtain a sharper cutoff frequency response. Frequency responses of the filters from measurements are in good agreement with those simulated using IE3D in the 5–9 GHz range. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010. |
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Keywords: | bandpass filters cascade circuits electromagnetic coupling interdigital capacitors transmission zeros |
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