ELECTROMAGNETIC TRANSDUCER FOR ASSESSING INTEGRITY OF BRAIDS OF SINGLE-LAYER PRINTED WIRING ON FLEXIBLE SUPPORT AND OF LAYERED MESO-STRUCTURES

摘要

The invention relates to an electromagnetic transducer meant for the assessment of the integrity of the braids of single-layer printed wiring on flexible support and of layered meso-structures. According to the invention, the transducer comprises an emitting part consisting of a coil () creating an incident electromagnetic field and a concentrator of alternating magnetic flux made of a metamaterial () coaxial with the emitting coil () which picks up evanescent waves diffracted on the conductive braids of printed wiring, and a receiving part consisting of a receiving coil () and a circular screen () made of a perfectly conducting material which is frontally placed as against the receiving coil (), provided with a circular aperture of very low diameter which ensure the diffraction of the evanescent waves and induce to the receiving coil () an amplitude- and phase-detected alternating electromotive voltage which depends on the type and structure of the braids of the printed wiring.