The drive towards a software-defined radio (SDR) in which much of the processing is controlled by reprogrammable digital hardware is placing new demands on the analogue RF front end. In order to facilitate multi-role multi-mode operation, this must impose the minimum of constraints on the parameters that can be defined in software, while still offering a performance which is at least as good as today's application-specific radios. This paper outlines some of the areas of research being carried out at the University of Bristol, funded by DERA, in an attempt to improve the flexibility and performance of the analogue RF front-end of a multi-role radio.