Dual-Wideband Filtering Power Divider With Good Isolation and High Selectivity

A new microstrip dual-wideband filtering power divider (FPD) is presented in this letter. The proposed device is mainly composed of a resonator loaded quarter-wavelength (λ /4) three-line coupled structure and a modified isolation network. To illustrate the design principle of the proposed FPD, equivalent circuits of the structure under the even-/odd-mode excitations are provided with the derived design equations. For demonstration, a prototype dual-band FPD operating at 2.3 and 3.64 GHz with 3-dB fractional bandwidths of 36.5% and 22.3% is designed, fabricated, and tested. Results indicate that the new FPD exhibits both good isolation and high frequency selectivity within the whole operation band.