Miniature dual-band filters using integrated bandpass and bandstop filters for wide bandwidths

Abstract

This paper presents a novel microstrip dual-band filter in which a shunt-stub bandpass filter and an open-stub bandstop filter are integrated into a single structure of short length. The bandstop filter is centered within the passband of the bandpass filter, resulting in a filter having dual passbands. Good return loss is obtained using an optimization routine. This method is suitable for designing dualband filters having wide bandwidths. Good agreement between theory and measurements in respect of low insertion loss and high isolation is demonstrated. Keywords: dual-band filter; open-stub bandstop filter; shunt-stub bandpass filter; wide bandwidth Classification: Microwave and millimeter wave devices, circuits, and systems References[1] H. Miyake, S. Kitazawa, T. Ishizaki, T. Yamada, and Y. Nagatom, "A miniaturized monolithic dual band filter using ceramic lamination technique for dual mode portable telephones," IEEE MTT-S Int.

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