The project focused on the development and validation of a radar sounder antenna for the JUICE mission to Jupiter’s icy moons. The core scientific effort was the creation of a detailed electromagnetic simulation model that could reproduce the behaviour of the RIME dipole antenna, including its layered construction of 250 µm carbon‑fibre‑reinforced polymer (CFRP) and a 50 µm silver skin. Because the full multilayer geometry is computationally expensive, the team introduced a homogeneous hollow‑cylinder approximation. By tuning the effective conductivity to 581 kS m⁻¹ the impedance and reactance of the simplified model matched the full model within acceptable limits for the 7.5–10.5 MHz operating band, although a perfect match of both magnitude and phase could not be achieved. The impedance comparison showed that the real part of the antenna resistance varied between 7.5 and 10.5 MHz, while the imaginary part displayed the expected resonant behaviour.

A second major technical contribution was the systematic study of the influence of coaxial cable lengths between the power amplifier, the central matching network, the terminal matching network, and the antenna. Four cable sections were examined for minimal, nominal, and maximal lengths, and the resulting reflection factors and received power were plotted against frequency. The analysis demonstrated that variations in cable length had a negligible effect on overall performance, a finding that was communicated to ESA and JPL to set tolerance limits for the final hardware. In parallel, the harmonics of the transmitted signal were extended from the nominal 7.5–10.5 MHz range to 6–50 MHz to assess electromagnetic interference. The extended impedance data were provided to JPL for further EMI studies, confirming that the second and third harmonics remained below critical thresholds.

The matching network (APN) was designed by JPL and evaluated by the university’s high‑frequency laboratory. Key performance metrics included the power delivered to the antenna ports and the phase stability across the band. The design aimed for a 180° phase difference between the two antenna ports, and the simulations confirmed that the chosen reactive components maintained this condition over the full frequency range. A Python script was developed to accelerate the analysis of different APN topologies, enabling rapid iteration during the design phase. Additional investigations explored the effect of a graphene coating on the antenna surface, the tolerance to amplitude and phase imbalance, and the impact of a tilted feed port configuration.

Experimental validation involved several stages. A 1:18 scale model of the spacecraft was measured to verify the antenna simulator’s de‑embedding procedure. Field tests were conducted at the Physikalisch‑Technische Bundesanstalt (PTB) in Braunschweig, where the full‑scale antenna was exposed to realistic environmental conditions. The measured radiation patterns and received power at a transmitted level of 0 dBW were compared with simulation results, showing good agreement. The system simulator and STI performance tests were also completed, confirming that the integrated radar sounder met the mission’s signal‑to‑noise and bandwidth requirements.

Collaboration was multi‑institutional. The project was led by the Institute of Communications Engineering at the University of Stuttgart, with key partners including the European Space Agency (ESA), the Jet Propulsion Laboratory (JPL), and Airbus Defence and Space. The German Ministry of Education and Research provided funding under grant number 50 QJ 1901. The project spanned from early 2022 through the submission of the final report on 22 January 2024, encompassing design, simulation, laboratory testing, and field validation. The combined effort delivered a validated antenna model, a robust matching network design, and a comprehensive set of performance data that support the successful deployment of the JUICE radar sounder.