Design of a broadband multilayer coupler for UWB beamforming applications

In this paper, the design of a new 3 dB-compact microstrip coupler which works over an ultra wide-band from 3 to 10.6 GHz is presented. The proposed directional is a multilayer slot-coupled directional coupler composed of two lozenge microstrip lines coupled through a hexagonal-shaped slot etched on a common ground plane. The design exhibits a coupling of 3 dB in a band of 3 to 10.6 GHz, the return loss and isolation are less than 22 dB over the operating frequency band.