GNSS-R antennas
Antennas for GNSSR
The research focuses on designing antennas for GNSS reflectometry (GNSS-R) experiments conducted aboard a 1U CubeSat constellation. In GNSS-R, a dedicated receiver captures both the direct GPS signal and its ground-reflected counterpart, enabling Earth observation applications such as soil moisture mapping, ocean surface wind retrieval, and ice sheet monitoring. The antenna design is therefore a critical subsystem, as it must simultaneously satisfy stringent performance requirements and the severe mechanical constraints imposed by the CubeSat form factor.
A fundamental challenge is the need to achieve substantial gain within a severely limited aperture area. In a 1U CubeSat (100 mm × 100 mm × 100 mm), the available mounting surface constrains the maximum antenna aperture, which in turn places an upper bound on achievable directivity for non-deployable solutions. Two broad design categories exist: deployable antennas, which can extend beyond the satellite body after launch to offer larger apertures, and non-deployable antennas, which are constrained to the CubeSat outer surface but offer simpler mechanical integration. Representative examples of deployable designs include helical antennas, which provide inherent circular polarisation and moderate gain, as well as deployable reflector and turnstile configurations. Non-deployable options include microstrip patch antennas and printed slot antennas, which trade gain for packaging simplicity.
The polarisation requirement for the nadir-pointing (downward-facing) receive antenna is left-hand circular polarisation (LHCP).
Material selection for both the antenna elements and any dielectric substrates must be compatible with the low Earth orbit (LEO) environment. Thermal and environmental factors must also be addressed at the design stage.
Activities
Some interesting papers I found in the topic:
- D. Sharma, D. K. Sharma, S. Kulshrestha and M. B. Mahajan, “High Gain Wideband Dual Circularly Polarized Microstrip Patch Antenna for GNSS Reflectometry,” 2023 IEEE Microwaves, Antennas, and Propagation Conference (MAPCON), Ahmedabad, India, 2023, pp. 1-5, doi: 10.1109/MAPCON58678.2023.10463935.
- S. Abulgasem, F. Tubbal, R. Raad, P. I. Theoharis, S. Lu and S. Iranmanesh, “Antenna Designs for CubeSats: A Review,” in IEEE Access, vol. 9, pp. 45289-45324, 2021, doi: 10.1109/ACCESS.2021.3066632.
Other space project that I found interesting:
CosmoCube
CosmoCube is a joint scientific mission developed by a collaboration of universities, including University of Cambridge, and space research institutions, aiming to place a small satellite into lunar orbit to study a poorly understood chapter of cosmic history. By observing from the far side of the Moon — shielded from Earth’s radio interference — the spacecraft will attempt to detect ancient hydrogen emission signals from the early Universe, spanning the period known as the cosmic Dark Ages through to the Epoch of Reionisation. The goal is to map structure formation in the early Universe and potentially uncover evidence of exotic physics, opening up an enormous volume of cosmic history that has so far remained completely inaccessible to astronomers.
