subject: What is RFI Shielding? [print this page] Many kinds of equipment require the use of RFI shielding for practical and legal purposes. For example, telecommunications devices need the shielding to prevent radio transmissions from distorting signals between devices near the same frequency.
RFI shielding essentially prevents electromagnetic pulses from interfering with the proper functioning of electronics. There are three factors that need to be operating simultaneously to interfere with electronic products: an interference source, an interference receptor, and a connection between the source and the receptor. The electromagnetic pulses may come from within the equipment itself, or they could originate from the outside. The shielding also protects other external equipment from potential interference caused by the product emitting the pulses.
RFI shielding for plastics can be accomplished with different forms: foil and conductive fabrics metallic inner shields RFI shielding compounds Vacuum metalization Electroless plating Conductive paints Shielding reduces RFI by reflecting and/or absorbing conductive materials. Equipment enclosures and circuit boards are common areas for shielding. If shielding is used correctly, it can protect electronic systems from external radiation by breaking the path of electromagnetic waves. Lower frequencies need thicker shielding to absorb wave energy, while higher frequencies require a thin shielding that mostly reflects wave energy. The distance between the shield and source of electromagnetic energy, as well as the shields material properties and energys frequency, will determine shielding performance.
The benefits of RFI shielding include: Outstanding Adhesion and Conductivity provides excellent ESD/EMI/RFI Shielding performance Cost-effective alternative to conventional RFI shielding methods Repeatability of coating conductivity and thickness Precision masking provides consistent mask line control Thin film coatings will not interfere with product assembly Uniform shielding coverage on complex substrates Coatings for RFI shielding can be applied to most plastics UL approval on most plastics Vacuum Technologies, Inc. RFI/EMI Shielding and Gasketing. 18 Jan. 2010 [http://www.vactecinc.com/index.htm].
