Design and Testing of the Quasi-Optical Network for the MetOp-SG Microwave Sounder

We describe the design and performance of the quasi-optical network (QON) that has been manufactured for the Microwave Sounder (MWS) instrument on the MetOp Second Generation weather satellite programme. The QON is a distribution network for eight receivers operating at different frequencies or polarisations and fed from a common antenna. It will provide a considerable improvement in spatial resolution and sensitivity compared to instruments currently in operation.