Performance assessment of EMC coatings

The interest about the Electro Magnetic Compatibility (EMC) and electro magnetic environmental pollution in the last years is reflected in the worldwide standardization process. In part[culai, the European 89/336/FEC Directive and the related technical standards have forced producers of electric and electronic devices to find out new solutions in order to reduce the electromagnetic emissions and susceptibility. To the purpose the equipment has to be protected by an external shield, which in cases where equipment housings are made in non-conductive polymeric materials can be provided by a proper conductive coating. In the paper a detailed test procedure to evaluate the fundamental parameters of conductive coatings with electromagnetic shielding properties is proposed. In particular new test methods and experimental results that involve the use of an anechoic chamber and other instrumentation suitable to define the electric, magnetic and screening effectiveness characteristics of EMC shielding coatings and their active components are described.