| 摘要 |
A method and apparatus for determining the shielding effectiveness of an RF gasket installed between two mating metallic surfaces of equipment or a structure by creating a time varying current flow from one of the mating surfaces to the other across the RF gasket, and sensing the current density of the time varying current in the vicinity of the gasket as a measure of shielding effectiveness. Two spaced electrodes, in the form of circular metal discs with a layer of dielectric material, are placed adjacent and substantially parallel to respective ones of the two metallic surfaces mated by the RF gasket with the gasket lying in the space between the electrodes. The electrodes are arranged to capacitively create a time varying current flow in the mating metallic surfaces between the electrodes. The current density in the metallic surfaces is sensed at a fixed position between the electrodes as a measure of gasket shielding effectiveness. The current density signal from the probe preferably is amplified and digitized so it can be stored and supplied directly to a computer. The current probe output can be calibrated in a laboratory against gaskets of know shielding effectiveness so as to provide a direct measure of gasket shielding effectiveness.
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