An UWB planar out-of-phase power divider employing microstrip-slot and parallel stripline-microstrip transitions

The design of a planar out-of-phase power divider with an ultra wideband (UWB) performance is presented. The device employs two substrates with a common ground plane. A coupling between two microstrip lines on the top and bottom substrate layers through a slot in the common ground plane, and a transition from two microstrip lines to a parallel stripline are used to achieve an UWB operation. The simulated and measured results of the proposed divider reveal low insertion losses, good return loss at the three ports and fine isolation between the two output ports across the band 3.1 to more than 11 GHz with high phase stability.