The measurement of the fuel mixture remains a very difficult task in thermonuclear plasmas, where the hydrogen isotopes are fully stripped and do not emit line radiation. A direct determination of the ion species mix will be essential in the reactor to keep the mixture close to 50/50 and maximize the fusion output. Moreover, a good measurement of relative concentration of atoms with different charge to mass ratio would allow a better control of the heating power deposition profile and the transport of particles of different masses is an important issue to understand particle transport coefficients. Fast Wave Reflectometry, with the potential capability to provide fuel isotope mix ratio with good spatial and temporal resolutions, is expected to be a valuable diagnostic for ITER. Experiments performed at DIIID tokamak have shown that this technique is quite promising to provide fuel isotope mix ratio within a few percent resolution. Here we present a system design with improved performance that uses a novel signal generation and coherent signal detection capable of operating in ITER-like scenarios.