Passively Pointing Directional Satellite Antenna By Leveraging Earth's Magnetic Field

CubeSats have become a big player in the satellite arena not only for education missions, but also as operational platforms. Accordingly, the performance demand on these volume- and power-limited satellites have drastically increased in the recent years. The demand for higher data throughput capabilities has been increasing, so more CubeSats are choosing S- and X-band communication options in order to meet the increasing data rates. Due to the limitations on link margin for CubeSats, use of S- and/or X-band necessitates a higher-gain, directional antenna. The main problem is that these antennas require accurate attitude determination and pointing, which can often become power-, volume-, and cost-prohibitive for CubeSat projects. The method proposed uses a permanent magnet to passively orient the satellite antenna towards the nadir direction. For satellites contacting higher-latitude ground stations, aligning the patch antenna in the direction of the magnetic dipole is enough to acquire the ground station within its half-power beamwidth. This research investigates the feasibility of using a permanent magnet onboard a CubeSat to passively point the antenna towards the ground station in the absence of other active attitude control systems. The study characterizes the expected communication link performance for a typical 3U CubeSat when implementing the proposed communication architecture using a S- or X-band patch antenna.