A tunable patch antenna includes a dielectric substrate having first and second surfaces. An electrically-conductive sheet is coupled to the first surface, and a patch assembly is coupled to the second surface. The patch assembly includes an electrically-conductive base fixedly coupled to the second surface and an electrically-conductive disk rotatably coupled to the substrate. The base has a substantially circular void wherein a perimeter region of the base circumscribes the void. The base has an electrically-conductive run extending from the perimeter region to a feedpoint location within the void. The disk has a diameter greater than a diameter of the void such that the disk is in contact with the perimeter region of the base. The disk has a slot cut through it that is aligned with a center of the disk.