Design of a 45-degree Linearly-polarized Hollow-waveguide Slot Two-dimensional Array Antenna with a Full-corporate-feed Circuit in the Lower Layer

Hollow-waveguide slot array antennas [1] have been widely used in the milli-meter band since they do have neither radiation loss nor dielectric loss. Furthermore, they have been developed especially for military application such as radars. For commercial application such as fixed wires access system, mass production at low cost has been required and single layer hollow-waveguide slot array antennas [2] [3] have been developed to solve the problem. However, the bandwidth of gain is narrow due to the series feed and the long-line effect. To prevent the narrow bandwidth of gain, center-feed structure [4] and partially corporate feed structure [5] have been proposed. The bandwidth of gain was improved but increase of a blocking area leads to low aperture efficiency. The structure of the double-layer corporate-feed waveguide slot array [6] was proposed to achieve the wide bandwidth of gain and the high aperture efficiency. It can be mass-produced at low cost by diffusion bonding of laminated thin metal plates [7]. In this paper, we propose a 45-degree linearlypolarized configuration, placing inclined slots on a double-layer full-corporate-feed hollowwaveguide slot array antenna and design 4-element sub-array.