Aspect ratio of the aperture in oversized rectangular slotted waveguide arrays and the effects on antenna efficiency

The authors designed and fabricated oversized rectangular slotted waveguide arrays, with various size and aspect ratio of 76.5GHz. The aperture efficiency is evaluated as functions of aspect ratio of the aperture. As the result, oversized waveguide antenna has a potential to enhance the efficiency with the large width of waveguide provided the design of feed waveguide with uniform excitation would be established. Aperture efficiency in term of aspect ratio of the aperture should be assessed with the loss in the substrate taken into account in the next steps.