W-band waveguide 3dB directional coupler based on E-plane branch line bridge

In this paper, a W-band waveguide 3dB directional coupler based on E-plane branch line bridge is proposed. The structure of this coupler and the formulas used to determine the critical design parameters have been given. The measurement and simulation results show that all the features of the 3dB coupler, such as equal power split, reflection coefficient, isolation, are satisfied over 85-96 GHz.