IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 64, NO. 6, JUNE 2016
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CubeSat Deployable Ka-Band Mesh Reflector Antenna Development for Earth Science Missions Nacer Chahat, Senior Member, IEEE, Richard E. Hodges, Senior Member, IEEE, Jonathan Sauder, Mark Thomson, Eva Peral, and Yahya Rahmat-Samii, Fellow, IEEE Abstract—CubeSats are positioned to play a key role in Earth Science, wherein multiple copies of the same RADAR instrument are launched in desirable formations, allowing for the measurement of atmospheric processes over a short evolutionary timescale. To achieve this goal, such CubeSats require a high-gain antenna (HGA) that fits in a highly constrained volume. This paper presents a novel mesh deployable Ka-band antenna design that folds in a 1.5 U (10 × 10 × 15 cm3 ) stowage volume suitable for 6 U (10 × 20 × 30 cm3 ) class CubeSats. Considering all aspects of the deployable mesh reflector antenna including the feed, detailed simulations and measurements show that 42.6-dBi gain and 52% aperture efficiency is achievable at 35.75 GHz. The mechanical deployment mechanism and associated challenges are also described, as they are critical components of a deployable CubeSat antenna. Both solid and mesh prototype antennas have been developed and measurement results show excellent agreement with simulations. Index Terms—CubeSat antenna, deep space communications, deployable antenna, Earth Science, high-gain antenna (HGA), horn, mesh reflectors, radar, reflector antenna, remote sensing, telecommunication.
I. I NTRODUCTION
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ITH the recent advances in miniaturized RADAR and CubeSat technologies, launching multiple copies of a RADAR instrument is now possible. The RainCube mission, currently under development at NASA’s Jet Propulsion Laboratory (JPL), is a 6 U CubeSat precipitation RADAR [1], as illustrated in Fig. 1. A. Background About CubeSats and Deployable Antennas Thanks to the simplification and miniaturization of radar subsystems, the RainCube project at JPL has developed a novel architecture that is compatible with the 6 U class or even larger. The RainCube architecture reduces the number of components, power consumption, and mass by over one order of magnitude, with respect to existing spaceborne radars. Therefore, it opens up a new realm of options for low-cost spacecraft platforms,
Manuscript received June 03, 2015; revised December 21, 2015; accepted January 31, 2016. Date of publication March 24, 2016; date of current version May 30, 2016. This work was supported by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. N. Chahat, R. E. Hodges, J. Sauder, M. Thomson, and E. Peral are with the Jet Propulsion Laboratory (JPL), California Institute of Technology, Pasadena, CA 91109 USA (e-mail:
[email protected]). Y. Rahmat-Samii is with the University of California Los Angeles (UCLA), Los Angeles, CA 90095 USA (e-mail:
[email protected]). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TAP.2016.2546306
such as CubeSats and SmallSats, with obvious savings not only on the instrument implementation (especially beyond the first unit) but also on the spacecraft and launch costs. We can now actually consider deploying a constellation of identical copies of the same instrument in various relative positions in low Earth orbit (LEO) to address specific observational gaps left open by current missions that require high-resolution vertical profiling capabilities. The RainCube instrument configuration is a fixed nadirpointing profiler at Ka-band [1], with a minimum detectable reflectivity better than +12 dBZ1 at 250-m range resolution and 10-km horizontal resolution at an altitude of 450–500 km. The key RainCube requirement relevant to the antenna is the 10-kmdiameter instantaneous RADAR footprint, which defines the antenna directivity and beamwidth (42 dBi) and fits in a highly constrained volume (
