A reconfigurable holographic antenna includes a metamaterial layer and a waveguide with at least one ridge. The metamaterial layer includes an array of tunable slots configurable to form holographic diffraction patterns. A reactance of each tunable slot in the array of tunable slots is individually tunable. The at least one ridge influences coupling between tunable slots in the array of tunable slots. The holographic diffraction patterns formed by the array of tunable slots generate a desired antenna wave in response to a received feed wave.