Abstract: The present invention relates to a method and related apparatus for the nondestructive determination of n layers of coating of a target having n layers of dielectric coating applied to an electrically conductive base material, comprising; a generator of electromagnetic waves in the microwave frequency range, including a microwave oscillator, a waveguide attached to the oscillator output and having an output aperture, a voltage detecting diode disposed within the waveguide, a flat layer of material adapted to be placed in a position abutting the target and disposed over the aperture of the waveguide and having a thickness t which, together with the waveguide, will provide a fixed distance between the diode and the target, and a display responsive to the output of the detecting diode for indicating the layer characteristics of the dielectric coating on the electrically conductive base material.