Scanned slot array fed by inclined slots in ridge waveguide

A novel linear array radiating element for use in a large low-sidelobe, planar slot array electronically scanned in elevation is described. The planar array consists of many horizontal resonant linear array elements, the polarization of which is horizontal. A longitudinally-slotted waveguide antenna linear array coupled with inclined slots cut in broad wall of ridge waveguide is presented. A 28-element linear array at X band was fabricated and measured to verify the validity of the design. The measured sidelobe level is less than -33dB over the entire the bandwidth. The thickness of the radiating array is only 10mm, more less than the slots array in the narrow wall of waveguide.