Dual-Mode Filtering Power Divider With High Passband Selectivity and Wide Upper Stopband

A novel microstrip dual-mode filtering power divider (FPD) is presented in this letter. Stemming from the distinctive voltage distribution along an open-ended one-wavelength (λ) microstrip line, the dual-mode FPD is initially constructed by utilizing proper coupling topologies between the open-ended transmission line and two dual-mode resonators. Meanwhile, its good isolation performance is attained by introducing an isolation resistor between the two dual-mode resonators. Next, the explicit synthesis method is described to design the proposed FPD with prescribed performance. A prototype FPD at 2.4 GHz is in final implemented and measured. As theoretically expected, this proposed FPD exhibits better than 22-dB isolation within the entire operation band along with 17-dB harmonic suppression up to 7.5 GHz (3.1f
₀
).