A radial line slot antenna comprising: an antenna feed configured to launch a cylindrical feed wave; a ground plane; an interstitial conductor; an array comprising a plurality of scattering elements; an edge element (207, 208); a first layer having a first cylindrical cavity formed between the ground plane and the interstitial conductor and being coupled to the antenna feed such that the feed wave propagates into the first cylindrical cavity outwardly and concentrically from the feed; a second layer having a second cylindrical cavity formed between the array and the interstitial conductor and coupled to the first layer, wherein the edge element (207, 208) is coupled to an outer edge of the ground plane and an outer edge of the array to form a third cavity connecting the first and second cylindrical cavities, such that the feed wave propagating outwardly is reflected at the edge element (207, 208) and propagates inwardly through the second cylindrical cavity from the edge element (207, 208); a controller configured to apply a control pattern to control the plurality of scattering elements such that a beam is generated, and the array having the plurality of scattering elements coupled to the second layer, wherein the array is configured such that an interaction of the feed wave with the plurality of scattering elements of the array generates the beam, wherein the controller is configured to tune each scattering element of the plurality of scattering elements to provide a desired scattering at a given frequency by using a voltage from the controller to dynamically reconfigure the beam, and wherein the array comprises a plurality of patches (301, 405A) and a plurality of slots, the plurality of patches and the plurality of slots forming the scattering elements, wherein each of the patches (301, 405A) is co-located over and separated from a slot in the plurality of slots and forming a patch/slot pair, each patch/slot pair being configured to be turned off or on based on application of a voltage to the patch (301, 405A) in the pair specified by a control pattern, and a liquid crystal layer disposed between each slot of the plurality of slots and its associated patch (301, 405A) of the plurality of patches (301, 405A). an antenna feed configured to launch a cylindrical feed wave; a ground plane; an interstitial conductor; an array comprising a plurality of scattering elements; an edge element (207, 208); a first layer having a first cylindrical cavity formed between the ground plane and the interstitial conductor and being coupled to the antenna feed such that the feed wave propagates into the first cylindrical cavity outwardly and concentrically from the feed; a second layer having a second cylindrical cavity formed between the array and the interstitial conductor and coupled to the first layer, wherein the edge element (207, 208) is coupled to an outer edge of the ground plane and an outer edge of the array to form a third cavity connecting the first and second cylindrical cavities, such that the feed wave propagating outwardly is reflected at the edge element (207, 208) and propagates inwardly through the second cylindrical cavity from the edge element (207, 208); a controller configured to apply a control pattern to control the plurality of scattering elements such that a beam is generated, and the array having the plurality of scattering elements coupled to the second layer, wherein the array is configured such that an interaction of the feed wave with the plurality of scattering elements of the array generates the beam, wherein the controller is configured to tune each scattering element of the plurality of scattering elements to provide a desired scattering at a given frequency by using a voltage from the controller to dynamically reconfigure the beam, and wherein the array comprises a plurality of patches (301, 405A) and a plurality of slots, the plurality of patches and the plurality of slots forming the scattering elements, wherein each of the patches (301, 405A) is co-located over and separated from a slot in the plurality of slots and forming a patch/slot pair, each patch/slot pair being configured to be turned off or on based on application of a voltage to the patch (301, 405A) in the pair specified by a control pattern, and a liquid crystal layer disposed between each slot of the plurality of slots and its associated patch (301, 405A) of the plurality of patches (301, 405A).