Single feed circularly polarized half E-shaped array: A compact assembly for dual-band Direct-to-Earth communications in Mars rovers

Establishing reliable and direct communications links from Earth to Mars rovers, also known as Direct-to-Earth (DTE) communications, is a complex and challenging antenna design problem. With the possibility of diminished UHF relay assets for the upcoming Mars 2020 mission, supporting such a technology requires a high performance antenna array system in order to enable substantial return of valuable scientific data. We propose a novel X-band single feed circularly polarized antenna subarray comprised of half E-shaped elements, optimized using Particle Swarm Optimization. The subarray architecture is modular, fed by a waveguide feed network, enabling high power handling capability. The subarray was prototyped and measured, showing good agreement between simulation and measurements. The design achieves excellent dual-band characteristics for uplink and downlink frequencies and is able to satisfy the required NASA DTE challenging system-level requirements.