An antenna device, comprising: a first conductive layer having a perimeter defined by one or more straight or curved lines; and an opening formed in the first conductive layer, defining a slot (1703, 1704, 1707, 1709),; a substrate having a first and second surface, the first conductive layer being formed on the first surface of the substrate; and a second conductive layer formed on the second surface of the substrate, the second conductive layer being coupled to the first conductive layer, characterized in that: the first conductive layer defines the slot (1703, 1704, 1707, 1709) and a coupling gap contiguous with the slot, the first conductive layer including a top ground 1705-1) and a floating metal plate region, the coupling gap providing a separation between the top ground and the floating metal plate region; wherein the second conductive layer includes a bottom ground, the bottom ground cleared away in a region of the second surface corresponding to a footprint of the slot (1703, 1704, 1707, 1709), the coupling gap, and the floating metal plate region projected from the first surface to the second surface; wherein the first conductive layer comprises a grounded coplanar waveguide feed, one end portion of which is conductively coupled to the top ground and conductively isolated from the floating metal plate region, while the other end portion is coupled to an RF signal port; wherein the floating metal plate region is conductively isolated from the top ground and the bottom ground; and wherein the first conductive layer defining the slot, the coupling gap, and the substrate form a composite right and left handed (CRLH) metamaterial structure. a first conductive layer having a perimeter defined by one or more straight or curved lines; and an opening formed in the first conductive layer, defining a slot (1703, 1704, 1707, 1709),; a substrate having a first and second surface, the first conductive layer being formed on the first surface of the substrate; and a second conductive layer formed on the second surface of the substrate, the second conductive layer being coupled to the first conductive layer, characterized in that: the first conductive layer defines the slot (1703, 1704, 1707, 1709) and a coupling gap contiguous with the slot, the first conductive layer including a top ground 1705-1) and a floating metal plate region, the coupling gap providing a separation between the top ground and the floating metal plate region; the first conductive layer defines the slot (1703, 1704, 1707, 1709) and a coupling gap contiguous with the slot, the first conductive layer including a top ground 1705-1) and a floating metal plate region, the coupling gap providing a separation between the top ground and the floating metal plate region; wherein the second conductive layer includes a bottom ground, the bottom ground cleared away in a region of the second surface corresponding to a footprint of the slot (1703, 1704, 1707, 1709), the coupling gap, and the floating metal plate region projected from the first surface to the second surface; wherein the first conductive layer comprises a grounded coplanar waveguide feed, one end portion of which is conductively coupled to the top ground and conductively isolated from the floating metal plate region, while the other end portion is coupled to an RF signal port; wherein the floating metal plate region is conductively isolated from the top ground and the bottom ground; and wherein the first conductive layer defining the slot, the coupling gap, and the substrate form a composite right and left handed (CRLH) metamaterial structure.