Compact grating lobe filter for short slotted waveguide array

A technique for reducing the height of the grating lobe filter generally used with the broadwall slotted waveguide arrays is described. A four-element array was designed and developed at 5.3 GHz to give very low sidelobes and grating lobes using the present technique. Experimental results are presented to demonstrate the effectiveness of the technique. The combination of parallel plates and choke slot at the aperture resulted in the reduction of the height of the plates. The technique reduces the height of the plates by 80% compared to the size suggested by Gruenberg.<>