A proposal of modification in ASTM D4935 test procedure for the shielding effectiveness (SE) evaluation of conductive plastic materials is presented in this paper. The aim is to minimize measurement errors and to improve repeatability and comparison of meas-urement results. This is particularly important especially with shields made of filled plastic materials, where the volume fraction and distribution of the conductive filler, as well as the morphology of its particles can significantly affect the conductivity of the composite and its SE accordingly. These sources of uncertainty, as well as current standardized assessment procedures adopted by the majority of plastic manufacturers for initial qualification of EMI shielding materials are examined in detail. Although in general only a relative value can be acknowledged to the measured SE values, the suggested methodology provides manufacturers of conductive plastic materials with data from which composite materials can be more reliably designed.
Survey of shielding effectiveness assessment of conductive plastic materials
SANDROLINI, LEONARDO
2004
Abstract
A proposal of modification in ASTM D4935 test procedure for the shielding effectiveness (SE) evaluation of conductive plastic materials is presented in this paper. The aim is to minimize measurement errors and to improve repeatability and comparison of meas-urement results. This is particularly important especially with shields made of filled plastic materials, where the volume fraction and distribution of the conductive filler, as well as the morphology of its particles can significantly affect the conductivity of the composite and its SE accordingly. These sources of uncertainty, as well as current standardized assessment procedures adopted by the majority of plastic manufacturers for initial qualification of EMI shielding materials are examined in detail. Although in general only a relative value can be acknowledged to the measured SE values, the suggested methodology provides manufacturers of conductive plastic materials with data from which composite materials can be more reliably designed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.