Comparative study of antenna elements for TDRSS enhanced multiple access system

The tracking and data relay satellite system (TDRSS) is a constellation of geosynchronous satellites, which are the primary source of space-to-ground voice, data and telemetry for the space shuttle. The satellites also provide communications with the International Space Station and scientific spacecraft in low-Earth orbit such as the Hubble Space Telescope. Integral to the design of the TDRSS class of satellites is an architecture consisting of a multiple access (MA), S-band, phased array antenna. This MA system receives and relays data simultaneously from five lower data-rate users and transmits commands to a single user. This paper describes a study (design, fabrication, and testing) of several modified antenna elements for the enhanced MA phased array. Several antenna elements were investigated including a helix antenna, a novel short backfire antenna excited with a circular waveguide, and a corrugated horn antenna. The results for each element in terms of performance; fabrication, assembly and tuning complexity; size and mass are compared