Method and apparatus for determining RE gasket shielding effectiveness

Apparatus for determining, in situ, the shielding effectiveness of an RF gasket installed between two mating metallic surfaces comprising:

• means for creating a time varying current flow between said mating surfaces across the gasket;
• and
• means for sensing current density of said time varying current flow between said surfaces in the vicinity of the gasket as a measure of gasket shielding effectiveness,
• wherein said means for creating a time varying current flow comprises a pair of discs with substantially flat upper and lower surfaces lying in substantially the same plane with a fixed spacing between the edges thereof and positionable with the lower surfaces adjacent the two mating surfaces and the gasket in the space between the edges of the discs, and means for applying a time varying electrical signal between said discs.

Apparatus for determining, in situ, the shielding effectiveness of an RF gasket installed between two mating metallic surfaces comprising:

• means for creating a time varying current flow between said mating surfaces across the gasket;
• and
• means for sensing current density of said time varying current flow between said surfaces in the vicinity of the gasket as a measure of gasket shielding effectiveness,
• wherein said means for creating a time varying current flow comprises a first electrically conductive disc positioned adjacent one of the surfaces on one side of the gasket, a second electrically conductive disc positioned adjacent the other of the surfaces on the other side of the gasket, and means for applying a time varying electrical signal between said first and second discs, said discs being spaced from said surfaces by a dielectric medium such that each disc acts as a plate of a capacitor and each surface acts as a plate of a capacitor, the time varying current in the surfaces being created by capacitive coupling.

Apparatus for determining the shielding effectiveness of an RF gasket installed between two mating metallic surfaces of equipment or a structure comprising:

• a pair of electrically conductive members each having a relatively flat surface lying in substantially the same plane, the conductive members being separated by a fixed distance to provide a space therebetween;
• a layer of dielectric material on each of the relatively flat surfaces of the conductive members;
• means for applying a time varying electrical signal between the conductive members;
• and
• a current sensing probe for sensing the flow of time varying current in an underlying surface without contacting such surface, said probe being disposed in the space between the conductive members in fixed relation thereto.