Summary
International Symposium on Antennas and Propagation
2010
Session Number:4FD2
Session:
Number:4FD2-2
Novel Tri-band Microstrip Bandpass Filter Using Crossed Open Stubs with Different Lengths
Wenjie Feng, Wenquan Che, Quan Xue,
pp.-
Publication Date:2010/11/23
Online ISSN:2188-5079
Summary:
In recent years, with the development and critical requirements on modern communication technology, more and more attentions have been paid to the multiband and multimode wireless communication systems. Tri-band microstrip bandpass filters (BPFs) play an important role in tri-band transceiver. Several tri-band BPFs have been implemented using stepped impedance resonators (SIR) due to their multi-band behaviors, simple structure and well-established design methodology [1]-[4]. However, the resonance frequencies of the SIRs are dependent, the filter design is quite complicated and it is not convenient to meet specific bandwidth requirement. One of the most effective methods to realize high performance BPF is to create transmission zeros located at upper or lower side of the passband [5]-[7]. Some tri-band BPFs using dual behaviors resonators (DBRs) and crossed open/short stubs are proposed in [8]-[9]. In [8], each passband of the filters is separated by the transmission zeros produced by the resonance of the open stubs, however, multi-section open stubs with different impedances should be cascaded to realize different transmission zeros, thus causing large filter size. To achieve simpler and more compact design for tri-band BPF, a new tri-band BPF operating at 2.45/5.25 GHz (WLAN bands) and 3.5 GHz (WiMAX) is proposed in this letter. Transmissions zeros created by the crossed open stubs are used to realize the passband and improve the performance of the passband, while ABCD matrix is used to determine the initial structure parameters. The filters are constructed on dielectric substrate with εr = 2.65 and h = 1 mm.