Design of wideband filtering power divider with high selectivity and good isolation

A new microstrip wideband filtering power divider (FPD) is presented. By selecting proper coupling topology between a λ /4 short‐ended microstrip transmission line and two multimode resonators, a wideband FPD is initially constructed. Meanwhile, by wisely introducing an isolation resistor between the resonators, good port‐to‐port isolation of the FPD is obtained. For validation, one prototype wideband FPD operating at 2.24 GHz with the fractional bandwidth of 32.1% is designed, fabricated, and measured. Results indicate that the presented FPD exhibits not only a high‐frequency selectivity performance with the help of two out‐of‐band transmission zeros, but also better than 22.5 dB isolation within the entire operation band.