Parallel plate slot array fed by post-wall center-feed waveguide consisting of T-junctions

A feed waveguide consisting of T-junctions is used to reduce a blocking area of the post-wall center-fed parallel plate slot array. The width of the blocking area of the T-junction type is less than that of the cross-junction type by 0.5 lambda₀. The sidelobe level in the E-plane of the T-junction type is suppressed down to -9.4 dB while that of the cross-junction type is -7.8 dB. To suppress the reflection of the feed waveguide, a novel design procedure is presented to reduce the reflection, and its validity is confirmed experimentally.