Dual-Wideband Filtering Power Divider Based On Coupled Stepped-Impedance Resonators

A new approach to design dual-wideband filtering power divider (FPD) with high selectivity and wide stopband is presented. The proposed FPD is mainly composed of two pairs of tapped-line fed coupled stepped-impedance resonators and an isolation resistor. With this specific coupling structure, multiple transmission zeros are successfully generated, thus leading to a sharp skirt selectivity and a wide stopband. For demonstration, a prototype dual-wideband FPD operating at 2.43 and 5.06 GHz with size of 0.67λ
_g
× 0.68λ
_g
is designed, fabricated, and tested. The 3-dB fractional bandwidths are measured as 38.3% and 18.8%. Results indicate that the proposed FPD exhibits not only high selectivity with a 16-dB out-of-band rejection from 5.77 to 9.43 GHz but also a 19.8-dB port-to-port isolation within the whole operation band.