Compact ultra-wideband in-phase power divider using three-line coupled structure

A compact ultra-wideband in-phase power divider with planar structure is presented. The proposed device utilizes three-line parallel-coupled microstrip lines. To realize the required tight coupling for an ultra-wideband performance, a slotted ground is utilized underneath the coupled lines. Moreover, chip capacitors are connected between the central line and each of the side coupled lines. Both of the equivalent circuit and fill-wave electromagnetic simulations indicate that the presented device operates across the band from 3.1 to 10.6GHz, with good insertion loss, return loss and isolation.