Wideband in-phase power divider using cascaded parallel coupled microstrip lines

A compact wideband in-phase power divider is presented. The proposed device utilizes parallel coupled microstrip lines, connected in cascaded configurations, and a stepped impedance T-junction of microstrip line. To achieve tight coupling for wideband performance, a slotted ground is utilized under each of the parallel coupled lines. Moreover, chip capacitors are connected between the coupled lines to enhance the coupling. To improve isolation between the output ports, an isolation resistor is added between the microstrip lines that are connected to the output ports just before the coupled lines. The proposed structure provides 100% fractional bandwidth based on 15 dB isolation as the reference. The simulated results of the proposed divider show equal power division with less than 0.5 dB additional insertion loss and more than 13 dB return loss at all the ports with less than 1° phase imbalance across the band 1-3 GHz