Abstract: A surface impedance measurement device comprises a transmitting antenna producing a magnetic field in the area surrounding a material to be tested and a receiving antenna receiving the magnetic field. An electric voltage wobbled in frequency is applied to the transmitting antenna, and a circuit measures the voltage at the terminals of the second antenna. For the antennae to be applied on the same side of the material to be tested and of which the surface impedance is to be measured, the antennae are superposed by the intermediary of a dielectric wedge in a compact probe. The impedance measurements are then independent of the dimensions and geometry of the material.

Abstract: The invention relates to a method and to a structural element for protecting an aircraft against the building-up, when flying, of electrostatic charges on the external metallic surface of the aircraft normally coated with a finishing dielectric paint.The structural element of the aircraft is subjected to a treatment consisting in applying on the external metallic surface of the aircraft, prior to the depositing of the finishing paint, a resistive electrostatic protection layer having a surface resistivity of between 1 and 100 M.OMEGA. per square and being connected to the reference electric potential (i.e., ground or mass) of the frame or body of the aircraft.The the protective layer is provided, for example, by applying at least a paint layer forming, once dry, a coating exhibiting the required surface resistivity.