Collinearly Fed Dual-Mode Stepped-Impedance Resonator Bandpass Filters

Collinearly fed dual-mode stepped-impedance resonator bandpass filters are proposed in this paper. By properly selecting the structural parameters, the first odd- and even-modes of a stepped-impedance resonator can be utilized to construct a dual-mode filter. A coupling and routing scheme is presented to model its operation. Four-pole filter of this type is also demonstrated. Measured results validate the analysis and theoretical prediction with good agreement.