Abstract: Sidelobe suppression and other beam transmission property manipulations in directional beam forming antennas is accomplished by means of a spatial filter. The filter geometry consists of a plurality of metallic gratings separated by air or other low dielectric constant dielectric substance. The filter is placed directly over the antenna radiating aperture and is encompassed by a tunnel structure of electromagnetic wave energy absorbing material. The shunt susceptance characteristics of the metallic gratings together with the integrating spacing distances are synthesized in a manner that effects full transmission of beam power in a selected beam direction while offering substantial rejection of it in other directions.

Abstract: Sidelobe suppression in directional beam forming antennas is accomplished by means of a spatial filter. The filter geometry consists of flat layers of high dielectric constant dielectric separated by air or other low dielectric constant dielectric substance. The filter is placed directly over the antenna radiating aperture and its dielectric materials have dielectric constant and thickness values that effect full transmission of beam power in a selected beam direction and substantial rejection of it in other directions.