DESIGN OF TRI-BAND MICROSTRIP BANDPASS FILTER USING FOLDED TRI-SECTION STEPPED-IMPEDANCE RESONATOR

摘要

A tri-band microstrip bandpass filter using folded trisection stepped-impedance resonators is designed, analyzed, and fabricated in this article. Furthermore, the filter's coupling structure analysis and equivalent circuit model are discussed theoretically, and the design methodology of tri-band filter is explained. Simulated and measured results verify that the central frequencies of the three passbands are located at about 1.6, 2.3, and 4.3 GHz, respectively. Besides, the circuit size of the proposed filter occupies only 26 × 26 (Mm)~2 (≈0.22λ_g × 0.22λ_g).