Deployable Circularly Polarized UHF Printed Loop Antenna for Mars Cube One (MarCO) CubeSat

Mars Cube One (MarCO) is the first interplanetary CubeSat Mission. NASA's Jet Propulsion Laboratory's twin CubeSats were launched to fly alongside the Mars lander InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) in 2018. MarCO A and B successfully relayed the spacecraft telemetry data from InSight during its Entry, Descent, and Landing (EDL) sequence directly back to Earth using the Deep Space Network (DSN). InSight sent the data to the two CubeSats via the UHF radio channel (401 MHz). The challenge of designing a UHF antenna for a small spacecraft (10×20×30cm
³
) is described in this paper. An innovative deployable loop antenna was used to meet the communication data link requirement with InSight. The loop antenna uses two baluns fed in phase quadrature to achieve right hand circular polarization (RHCP) and deploys from the spacecraft to provide a gain better than 2.5 dBi over ±30° from boresight.