Windowed Short-Slot Directional Coupler

A windowed short-slot directional coupler is realized by putting a rectangular resonant iris in the coupling area of a Riblet coupler.The return loss of the coupler can be reduced obviously by optimizing the dimensions of the resonant iris,which is very adaptable to use in a high performance power combining network.In the paper,a 3dB windowed coupler is designed and simulated and the simulation shows that both the return loss and isolation are less than-30dB,and the two outputs are-3±0.1dB compared with input at bandwidth 35±1GHz.Further,a 1∶ 8 power divider network formed by 7 windowed couplers is designed and simulated.The simulation result shows that the return loss is less than-20dB and all outputs are-9.15±0.15dB compared with input in the bandwidth 35±1GHz.