Wide Aperture Circularly Polarized Antenna for Small Telemetry Satellites

This paper focuses on the design of a telemetry antenna system intended for small satellites. It provides an axial ratio (AR) lower than 3 dB over ±60° conical space angle with over 20% of bandwidth. The antenna consists of a multilayer patch element fed by a wideband feeding circuit. The latter is an appropriate adjustment of 90° hybrid couplers and 180° ring coupler. We show that this design provides high-quality circular polarization properties for agile small satellites without having to suspend their mission to download their data and also without sacrificing the antenna low profile and wide bandwidth. The antenna is fabricated and the experimental performance is presented and followed by a discussion.