Abstract: Various examples are provided for flat lens antennas and their operation. In one example, among others, an antenna includes electrically thin (W<<?high), highly conducting, TEM mode antenna arms fed at a first end by a balun. The TEM mode antenna arms can be embedded in a spatially varied anisotropic dielectric material. A separation between the TEM mode antenna arms can increase from the first end to a second end where the TEM mode antenna arms transition to resistive card (Rcard) terminations when the TEM mode antenna arms are separated by a distance Hr, where a ratio of Hr to a height (H) of the antenna is in a range from about 0.2 to about 0.8.

Abstract: A plurality of end caps engagable with a microwave cavity each have an underside configured differently to cause the microwave cavity to have different electrical responses depending on which end cap engages the microwave cavity. A microwave device includes a cylindrical cavity and an end cap movable within the cavity to change its axial position within the cavity thereby varying the volume and the electrical response of the cavity.

Abstract: A modular payload structure providing standardized thermal, electrical and mechanical interfaces. The modular arrangement of the present invention has fixed radiator panels that have standard thermal and mechanical interfaces, allowing communication modules to "plug in" directly to the payload structure. In the case of high thermo-energy dissipating modules, heat pipes on the modules connect to the thermal interfaces and move energy from the modules to the thermal interfaces of the radiator panel.