Single polarisation active electronically steered array (AESA) technology is state of the art in modern radar systems. For future systems, an attractive evolution is multi-functionality. The idea is to use the radar antenna also for communication and electronic warfare applications. It is so attractive because it promises to reduce overall size, weight and power demands compared to a solution with individual systems. With new applications new requirements emerge, one of which is polarisation agility. At Hensoldt, a wideband AESA with selectable polarisation on plank level has been manufactured. This AESA has been used to test different polarisation concepts. The most relevant of these test results are presented in this paper.