Non-contact measurement of the electric field shielding performance and the resistivity of layer materials

An approach is described to measure the electric field shielding performance of materials as a function of frequency. This provides a broader appreciation of the performance of materials than is available from standard energy transfer type measurements. Materials that include metallic conducting components show little variation of shielding performance with frequency, whereas the performance of resistive materials falls away with increasing frequency. It is shown that the variation of attenuation with frequency relates to the resistivity on or within the material. This has particular practical relevance to the risk of occurrence of damaging or incendive electrostatic discharges from charged material surfaces.