We have developed at the ONERA research center an experimental set-up, denoted as EMIR (ElectroMagnetic InfraRed), which allows fast and accurate measurements of electromagnetic fields, at microwave frequencies, over a large probing surface. It consists in measuring the heating of a thin photothermal film located near the object under test by means of an infrared camera, this heating being proportional to the intensity of the electric field component tangential to the film. So far, this method was mainly used for the mapping of the electric field around objects. In order to extend its field of application, we are studying the feasibility of electromagnetic nondestructive evaluation of dielectric materials from data provided by the EMIR method, where the goal is to built up a map of the electromagnetic parameters of an unknown object from measurements of the scattered field that results from its interaction with a known incident wave.
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