An antenna for transfer of information or energy is described. The antenna includes an electrically conductive first layer having a width in a thickness direction of the antenna and extending longitudinally along a length of the first layer between first and second longitudinal ends of the first layer, and an electrically insulative thermally conductive second layer bonded to the first layer along the length of the first layer. The first and second layers are wound to form a plurality of substantially concentric loops. A width and a length of the second layer are substantially co-extensive with the respective width and length of the first layer so as to expose opposing longitudinal edge surfaces of the first layer along the length of the first layer. Coils and assemblies useful for making coils are also described.