UDAN: A Compact Deployable UHF Antenna Enabling High-Gain Links for CubeSats

The miniaturization of satellite platforms has imposed severe constraints on antenna systems, particularly for UHF links requiring high gain and polarization robustness. To address these challenges, this contribution introduces UDAN, a deployable UHF antenna concept designed to significantly enhance communication capabilities of CubeSats and other small spacecraft while remaining compliant with standard launch and deployment interfaces.

UDAN is based on a deployable quadrifilar helix architecture with an integrated ground plane, tailored for operation around 430 MHz and supporting a wide operational range from 400 to 460 MHz. The antenna is fully stowed within a 1.5U CubeSat volume and relies on a hold-down and release mechanism that enables autonomous deployment without motors or active actuators. Once deployed, the structure expands to approximately 1 m in diameter and 0.5 m in height, providing the electrical aperture required for high-performance radiation characteristics.

Electromagnetic simulations and experimental validation on multiple breadboard models demonstrate that the antenna provides circular polarization with a realized gain above 10 dBi across the target band. Measured results confirm excellent impedance matching near the center frequency and a high level of polarization purity, validating the beam-forming and feeding approach adopted in the design. Repeated deployment tests show consistent mechanical behavior and reliable release performance.

The proposed antenna is well suited for UHF TT&C and IoT-oriented CubeSat missions, enabling improved link margins and reducing dependency on complex ground infrastructure. The concept is also applicable to microsatellites, amateur radio payloads, and low-data-rate Earth-observation missions. UDAN demonstrates that high-gain, circularly polarized UHF antennas can be successfully integrated into nanosatellite platforms through innovative deployable solutions.