CAD of Cross-Coupled Miniaturized Hairpin Bandpass Filters

Mobile communication systems require a narrow-band BPF having low passband loss, high selectivity, small size and flat group delay. Such a filter response can be realized using filter with cross coupling between nonadjacent resonators. Normally this kind of filters is realized using waveguide cavities or dielectric resonators. This paper describes a method for CAD of cross-coupled BPF using miniaturized hairpin resonator. In contrast to the design techniques in [2,3] no full-wave electromagnetic (EM) simulator is needed here. Microstrip slow-wave open-loop filter is proposed in [2,3]. An earlier version of this paper was presented at the 37 International Conference on Information, Communication and Energy Systems and Technologies, ICEST 2002, October 1-4, 2002, Niš, Yugoslavia 1 Ilia Gergiev Iliev – assistant in Dept. of Radiotechnic in Faculty of Communications and Communication Technologies in TU –Sofia E-mail [email protected] 2 Marin V. Nedelchev – student in Dept. of Radiotechnic in Faculty of Communications and Communication Technologies in TU –Sofia E-mail [email protected] Synthesis algorithm of BPF composed of adjacent coupled resonators is described in [1,5]. Cross-coupled structures are shown in fig.3. This type of coupling reduces the filter size.