“Reduction of Aperture Blockage in the Center-Feed Alternating-Phase Fed Single-Layer Slotted Waveguide Array Antenna by E- to H-Plane Cross-Junction Power Dividers”

The alternating-phase fed single-layer slotted waveguide array antenna, which dispenses with the electrical contact between the narrow walls and the slotted plates, has been developed for low cost wireless communication systems, radar systems, etc. The center-feed is introduced to increase antenna bandwidth by having the long line effects associated with the end-feed one. However, the large blocking area at the center of the array aperture causes high first side-lobe levels (about -10 dB). In this paper, the authors propose a cascade of "E- to H-plane cross-junctions" as a new single-layer feed waveguide with reduced blockage. It is in single-layer without inductive posts and is mass producible by die-casting techniques. The antenna characteristics and sidelobe reduction are confirmed by simulation and experiment.