Design of A Tunable Dual-Band Filter Using Step-Impedance Resonators with Wide Stopband

摘要

This paper presents a tunable dual-band microsrtip filter using step-impedance resonators (SIR) with wide stopband and low insertion loss. The dual-band filter employs two SIR single-band filters for the specifications of the two passbands respectively and using novel layout to make the two single-band filter can be designed independently and achieve wide stopband. A prototype dual-band filter operated at 2.07 and 3.15 GHz is designed and fabricated. The upper stopband is extended over 10GHz. Good agreement achieved between the numerical and measured results.