Small-Profile High-Gain Metal-Foil Antenna Element: Design and Radiation Characteristics for Lunar Lander Communications

The feasibility of small-profile, low mass, high-gain all-metal or metal-foil antenna elements for constructing large array antennas is investigated. The metal-foil antenna elements are of the short backfire type, and three different designs are studied with cylindrical, hexagonal, and concave main reflectors, respectively. The antenna elements are fabricated using polished thin copper-foil (0.005 inch thick). The design frequency fd for the antenna elements is 8.45 GHz and the feed is an open-ended WR90 rectangular waveguide. The antenna elements radiate or receive a linearly polarized signal. The paper presents the measured performance for all three variants. The antenna elements have excellent return loss bandwidth, high gain, high aperture efficiency, almost equal E-and H-plane beamwidths, and low cross-polarization level. Additionally, the profile height and mass of the metal-foil antenna elements are compared with that of a pyramidal horn antenna of comparable gain and shown to be smaller. The above results indicate that the metal-foil antenna elements can be used as a building block for constructing large array antennas that have low profile, light weight, high gain, and low cost for applications such as, direct to Earth communications from landers and rovers on the lunar surface.