A beam control assembly to shape a ribbon beam of ions for ion implantation includes a first bar, second bar, first coil of windings of electrical wire, second coil of windings of electrical wire, first electrical power supply, and second electrical power supply. It comprises an antenna element, a ground plane, an antenna feed-point, and at least one slot or slit formed on the ground plane. In one embodiment, a single tamper-resistant proximity server computes the distance between communication devices that are implemented as trusted applications on open platforms.