The objectives of this activity is to develop and validate test setups, techniques and methodologies that enable the verification of future large baseline Ka Band interferometric antennas.

Future high frequency interferometric antennas (e.g. at Ka band) using large baselines require verification and testing with a very high accuracy, in particular in phase. While such interferometric testing and ground calibration techniques have been successfully performed in the past (i.e. Cryosat), the consideration for baselines above 10 or 20 meters brings challenges in the ground validation in several domains: the antenna alignment, the boom effect on the antenna pattern and the synchronous co-alignment between all beams being generated are areas that require development to achieve satisfactory results, in line with the requirements. In addition, for baselines in the 15-20 meter range, the currently existing test facilities and techniques do not allow testing the complete baseline in deployed configuration. One of the solutions is to scale down the antenna sub-system, which would imply a measurement at frequencies in the order of a few hundred gigahertz - a challenge that once overcome, would allow a proper on ground characterisation of the complete system. A demonstrator of the scaled antenna sub-system shall be made available and tested to validate the testing concept The workflow of the activity is as follows: 1) Identification of accuracy requirements and problem areas in large Ka band SAR interferometers 2) Trade-off on verifications and testing methodologies 3) Design and manufacture of scaled breadboard 4) Testing of breadboard to validate concept