The application of the reconfigurable reflectarray structure to software-defined and cognitive radio is discussed for the first time. The main idea is that the reflectarray has the potential-in addition to dynamical beamforming-of simultaneous frequency and polarization reconfiguration or diversity/multiplexing gains, at low complexity and cost. We discuss the expected benefits of this potentially universally reconfigurable antenna system in the context of (MIMO) software-defined and cognitive radio. We also deduce the requirements on the controllable reflectarray unit cell phase characteristics and feed antennas, to achieve the desired novel reconfiguration capability.