A Compact Broadband Riblet-Type Three-Way Power Divider in Rectangular Waveguide

A compact broadband three-way power divider based on a Riblet type coupler is proposed and designed in W-band. Coupling occurs among three adjacent waveguides through narrow walls. Two cylindrical posts located in the coupling region, help to achieve efficient coupling within shorter length and also to reduce reflections. The tapering of the input central waveguide improves the return loss of the power divider. The proposed power divider is validated with experimental measurements and measured power division ratio is -5.2 dB ± 0.25 dB. The return loss and isolation between the output ports is better than 20 dB over 88.75-97.5 GHz frequency range. The amplitude imbalance between the output ports is less than ± 0.4 dB. The fractional bandwidth for the power divider is 9.47% and the coupling length is 1.7λg. The simulated and measured results are in close agreement.