Millimeter wave antennas are of recent interest due to their commercial applications for high data-rate links. However, at mm-waves, losses are of major concern. To mitigate losses, slotted waveguide antennas have been proposed due to their small power loss and low cost. For airborne transceivers, such antennas typically perform beam steering via frequency scan. However, beam steering using frequency variation is not suitable here since the beam direction is not fixed across the signal bandwidth, causing data rate variations.