Propagation in complex media can be thought of as an advantageous way to speed up antenna characterization. If the geometry of the medium is well controlled, the different reflections that take place can be fruitfully used for antenna radiation pattern (ARP) measurement. The feasibility of this concept is presented here for the case of a simple geometry. Preliminary results are presented and it is shown how frequency diversity can be fruitfully used to retrieve the free space radiation pattern (RP). A special care is given to the conditioning of the mathematical model as retrieving the free space radiation pattern consists in solving an inverse problem.