Understanding the mechanism of anomalous transport inmagnetically confined plasmas requires the use of sophisticateddiagnostic tools for the measurement of turbulent fluctuations. The articledescribes the results of an extensive numerical study of microwave reflectometryin tokamaks showing that the two dimensional structure of plasmafluctuations near the cut-off can be obtained from the phase of reflectedwaves. This requires the latter to be collected by an optical system making animage of the reflecting layer onto an array of microwave receivers, and theamplitude of fluctuations to be below a threshold that is set by thespectrum of poloidal wavenumbers. The conceptual design of an experimental schemefor the global visualization of turbulent fluctuations in tokamaks isdescribed.