Various ring cells are disclosed herein that include a metallic ring patch and a ring slot to transmit or receive radio frequency (RF) signals. The disclosed ring cells use several dielectric layers that are separated by a low-dielectric foam layer upon which the ring patch is positioned. The ring slot is located below the foam layer. An electrically conductive fence formed curved electrically conductive walls or a circular pattern of electrical vias is positioned around the ring slot. Electrical feed lines are used to either supply electrical power to the ring cells or output RF signals that are received by the ring patch.