A fast and precise method for the measurement of dielectric permittivity at microwave frequencies

A new procedure for monitoring dielectric permittivities at microwave frequencies is presented. It exploits an extension of the Cavity Perturbation Method. The core of this procedure consists in the analysis of the power reflected by a cavity at resonance by means of quick and narrow frequency sweeps which can be rapidly and smartly updated in order to track the resonance. The new method has been tested with an experimental setup herewith described. Some experiments have been addressed on samples undergoing chemical (polymerization) and physical (vaporization) changes and their results are also reported. The method can be implemented by the use of commercial devices and it can be easily automated for supporting field applications.