Design of Tri-Band Filters With Improved Band Allocation

• Published in: IEEE transactions on microwave theory and techniques Vol. 57; no. 7; pp. 1790 - 1797
• Main Authors: CHEN, Bo-Jiun, SHEN, Tze-Min, WU, Ruey-Beei
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.07.2009; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Allocations; Applied sciences; Band allocation; Band pass filters; Bands; Circuit properties; coupling matrix; Design methodology; Electric, optical and optoelectronic circuits; Electronic circuits; Electronics; Exact sciences and technology; Filtering theory; GSM; Harmonics; Microwaves; Multiaccess communication; Open loop systems; Oscillators, resonators, synthetizers; Passband; Resonance; Resonant frequency; Resonator filters; Resonators; Simulation; stepped-impedance resonators (SIRs); Harmonic; Resonator; stepped-impedance resonators (SIRs); Simulation; Stepped impedance device; coupling matrix; Passband; Band allocation
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2009.2022888

A new design method for tri-band filters with improved band allocation is proposed. The design concept treats different band allocations with different methodologies. For the bands assigned to adjacent frequency regions, transmission zeros are introduced to split one of the single bands into two. For the bands that are assigned separately, different harmonic modes of stepped-impedance resonators are used to realize different passbands. Two design examples with different responses and band allocations are given, and were verified by experiments, as well as full-wave simulation results.