A modified broadband hybrid-ring directional coupler in W-band

In this paper, a modified broadband hybrid-ring directional coupler is proposed. The 3D EM simulation results show that, from 75 GHz to 110 GHz, with an extra isolated arm, less than 0.25 degree phase difference and less than 0.03 dB amplitude difference are achieved by such coupler; in addition, a chamfer in the input arm increases the isolation between two output ports to more than 14.9 dB compared with conventional 5 ports hybrid-ring coupler. The new design could be applied in W-band balanced modulator and other power dividing situation.