Split Slots Array for Grating Lobe Suppression in Ridge Gap Guide

A frequency-scanning antenna array of nonresonant slots with uniform slot field distribution is designed using the ridge gap waveguide (RGW) technology. The slots are separated by one wavelength, which causes the presence of undesired grating lobe. In order to eliminate the grating lobe, the structure is split by a nonradiating longitudinal slot, which splits each slot into two halves. Each half is displaced along the nonradiating slot by a separation of half a wavelength. In order for each of the two halves to be excited in phase, a phase shifter of 180 ° is introduced to one side of the two halves. Such arrangement caused elimination of the grating lobes. The proposed configuration is fabricated, and measurement results are provided to prove the concept.