We report the intermediate results on a novel slotted waveguide antenna for point-to-point communications at Ka band. The antenna adopts an aperiodic layout with uniformly-excited elements capable of meeting the ETSI class II radiation pattern envelop in all planes with high aperture efficiency. A total of 16 regular waveguide subarrays with an aperiodic inter-column spacing along the E-plane are fed by a corporate feed network located underneath. The prototype was milled in three layers of aluminum and bonded by vacuum brazing. Measurements confirm a 15% impedance bandwidth. The simulated patterns satisfy the radiation pattern envelop and have a gain above 28.5 dBi over 29–31 GHz, corresponding to an efficiency better than 80%.