Effect of the Feeding T-Junctions in the Performance of Planar Waveguide Slot Arrays

An improved analysis procedure for planar waveguide slot arrays has been devised to evaluate the effect of the feeding T-junctions on the radiated far field. The T-junctions have been modelled as five-port networks. A hybrid matrix has been derived for each five-port network by analyzing the interaction between a T-junction and the slot couplers next to it with a method of moments (MoM) procedure. Then, the hybrid matrices have been properly inserted in the array equivalent circuit. The results of our model have been compared to those of a commercial software and with measured data, showing a very good agreement.