All-Metal Dual-Frequency RHCP High-Gain Antenna for a Potential Europa Lander

A new all-metal dual-frequency right-hand circularly polarized high-gain antenna (HGA) is under development at the National Aeronautics and Space Administration's Jet Propulsion Laboratory for a potential Europa Lander. The antenna must be primarily composed of metal to ensure survivability in the harsh environment of the Europan icy moon (i.e., very low temperature and high radiation). The antenna must also have a low profile to meet drastic volume constraints and have efficiencies higher than 80% at both the uplink and downlink X-band deep space frequency bands. This antenna is a key component for this potential mission as it enables direct-to-earth links rather than relaying signals via a nearby spacecraft. The proposed HGA consists of 16 subarrays fed by waveguides. An $8 \times 8$ subarray was fabricated to prove the antenna concept. A gain of 24.1 and 25.3 dBic was demonstrated at both frequency bands for the subarray. This translates into an aperture efficiency of 83% and 80% at uplink and downlink bands, respectively.