The Cassini mission constitutes the last big spatial enterprise of this century. It will investigate the Saturnian system, with particular interest for its larger satellite, Titan. A Ku band radar is included in the instrumentation. The radar will acquire data on 90% of Titan surface, operating as imaging radar, scatterometer, altimeter and passive radiometer. The possibility of retrieving information about physical and morphological properties of the surface is expected. In this work, a preliminary study about the simulation of expected e.m. response of Titan surface is performed. A fractal based model is employed to describe surface morphology, while Kirchhoff approximation is used to model e.m. response. The simulated data suggest the possibility of discriminating between three of the expected scenarios: a water ice surface, a water ice surface in presence of ammonia, liquid ethane surfaces.