Thermal performance evaluation of microwave remote sensing satellite’s tile antenna in radiation mode using a gaseous Nitrogen based thermal vacuum system

The microwave remote sensing satellite’s tile antennas are crucial for operational success. This study evaluates the thermal and RF behaviour of 1 m × 1 m honeycomb quartz tiles bonded with cyanate ester adhesive, tested in a gaseous Nitrogen–based thermal vacuum system at SAC-ISRO. Unlike conventional setups, the system achieved a temperature gradient of ≤ 2 K across the antenna surface, surpassing the standard requirement of ≤ 10 K. Strategic placement optimized radiation heat transfer, while precise shroud control ensured uniform thermal exposure during cycling between 253 K and 358 K. Radio Frequency (RF) measurements confirmed stable dual-polarization performance, with return losses consistently below 10 dB. Measurement uncertainties (±0.1 K for temperature sensors, ±0.05 dB for RF data) validated the robustness of results. The findings establish an integrated thermal–RF validation methodology, confirming antenna readiness for operational missions and contributing to reliable, cost-effective satellite systems.