A grating lobe filter for transverse slot arrays

The author presents a technique for preventing the grating lobes from radiating from a transverse slot array phased to generate a broadside beam. The grating lobes radiated from a sparse array are eliminated by the filtering action of a parallel plate region extending about half a wavelength in front of the array. This method works for arrays with longitudinal polarization. In addition, the impedance characteristics of a transverse slot array with and without the filtering section are demonstrated by measurements on a half-height waveguide array.<>