A X-mode reflectometer using an innovative design was developed and installed successfully at JET to investigate the viability of measuring density profiles with high spatial and temporal resolution in large size devices using broadband FM-CW Reflectometry. It probes the plasma in V band (0 up to 1.4¥1019 m-3), for magnetic fields between 2.4 and 3.0T. In this paper we discuss the main design options and implementation of the diagnostic. The first experimental results show a high sensitivity of the diagnostic when measuring plasma density profile changes occurring in ITER relevant regimes namely during ELMy H-modes.