Abstract: An electrically continuous, grounded conformal EMI protective shield and methods for applying same directly to the surfaces of a printed circuit board. The EMI shield adheres and conforms to the surface of the components and printed wiring board. The shield takes the shape of the covered surfaces while adding little to the dimensions of the surfaces. The EMI shield includes low viscosity, high adherence conductive and dielectric coatings each of which can be applied in one or more layers. The dielectric coating is initially applied to selected locations of the printed circuit board so as to be interposed between the conductive coating and the printed circuit board, preventing the conductive coating from electrically contacting selected components and printed wiring board regions. A high viscosity, non-electrically-conductive filler material is applied to printed circuit board regions that have surfaces that are cavitatious and/or which have a highly variable slope.

Abstract: An electrically continuous, grounded conformal EMI protective shield and methods for applying same directly to the surfaces of a printed circuit board. The EMI shield adheres and conforms to the surface of the components and printed wiring board. The shield takes the shape of the covered surfaces while adding little to the dimensions of the surfaces. The EMI shield includes low viscosity, high adherence conductive and dielectric coatings each of which can be applied in one or more layers using conventional spray techniques. The conductive coating prevents substantially all electromagnetic emissions generated by the shielded components from emanating beyond the conformal coating. The dielectric coating is initially applied to selected locations of the printed circuit board so as to be interposed between the conductive coating and the printed circuit board, preventing the conductive coating from electrically contacting selected components and printed wiring board regions.

Abstract: A decoupling circuit on a printed circuit board is disclosed. The decoupling circuit comprises an electrical filter circuit electrically connected between an interconnect post and a ground land of the printed circuit board. The ground land is connected to a ground plane in the printed circuit board. The electrical filter shunts conducted interfering signals received at the interconnect post to the ground plane. Components of the electrical filter circuit and ground plane form a first receiver loop in which induced interfering signals can be generated. The decoupling circuit also comprises a second receiver loop comprising a conductive coating of an EMI shield conformingly adhered to surfaces of the decoupling circuit, and a conductive path of the first receiver loop. The second receiver loop is adapted to have induced therein a signal having a direction and magnitude sufficient to cancel interfering signals induced in the first receiver loop.

Abstract: An electrically continuous, grounded conformal EMI protective shield and methods for applying same directly to the surfaces of a printed circuit board. The EMI shield adheres and conforms to the surface of the components and printed wiring board. The shield takes the shape of the covered surfaces while adding little to the dimensions of the surfaces. The EMI shield includes low viscosity, high adherence conductive and dielectric coatings each of which can be applied in one or more layers using conventional spray techniques. The conductive coating prevents substantially all electromagnetic emissions generated by the shielded components from emanating beyond the conformal coating. The dielectric coating is initially applied to selected locations of the printed circuit board so as to be interposed between the conductive coating and the printed circuit board, preventing the conductive coating from electrically contacting selected components and printed wiring board regions.

Abstract: A decoupling circuit on a printed circuit board is disclosed. The decoupling circuit comprises an electrical filter circuit electrically connected between an interconnect post and a ground land of the printed circuit board. The ground land is connected to a ground plane in the printed circuit board. The electrical filter shunts conducted interfering signals received at the interconnect post to the ground plane. Components of the electrical filter circuit and ground plane form a first receiver loop in which induced interfering signals can be generated. The decoupling circuit also comprises a second receiver loop comprising a conductive coating of an EMI shield conformingly adhered to surfaces of the decoupling circuit, and a conductive path of the first receiver loop. The second receiver loop is adapted to have induced therein a signal having a direction and magnitude sufficient to cancel interfering signals induced in the first receiver loop.

Abstract: An electrically continuous, grounded conformal EMI protective shield and methods for applying same directly to the surfaces of a printed circuit board. The EMI shield adheres and conforms to the surface of the components and printed wiring board. The shield takes the shape of the covered surfaces while adding little to the dimensions of the surfaces. The EMI shield includes low viscosity, high adherence conductive and dielectric coatings each of which can be applied in one or more layers using conventional spray techniques. The conductive coating prevents substantially all electromagnetic emissions generated by the shielded components from emanating beyond the conformal coating. The dielectric coating is initially applied to selected locations of the printed circuit board so as to be interposed between the conductive coating and the printed circuit board, preventing the conductive coating from electrically contacting selected components and printed wiring board regions.

Abstract: A decoupling circuit on a printed circuit board is disclosed. The decoupling circuit comprises an electrical filter circuit electrically connected between an interconnect post and a ground land of the printed circuit board. The ground land is connected to a ground plane in the printed circuit board. The electrical filter shunts conducted interfering signals received at the interconnect post to the ground plane. Components of the electrical filter circuit and ground plane form a first receiver loop in which induced interfering signals can be generated. The decoupling circuit also comprises a second receiver loop comprising a conductive coating of an EMI shield conformingly adhered to surfaces of the decoupling circuit, and a conductive path of the first receiver loop. The second receiver loop is adapted to have induced therein a signal having a direction and magnitude sufficient to cancel interfering signals induced in the first receiver loop.

Abstract: An electrically continuous, grounded conformal EMI protective shield and methods for applying same directly to the surfaces of a printed circuit board. The EMI shield adheres and conforms to the surface of the components and printed wiring board. The shield takes the shape of the covered surfaces while adding little to the dimensions of the surfaces. The EMI shield includes low viscosity, high adherence conductive and dielectric coatings each of which can be applied in one or more layers using conventional spray techniques. The conductive coating prevents substantially all electromagnetic emissions generated by the shielded components from emanating beyond the conformal coating. The dielectric coating is initially applied to selected locations of the printed circuit board so as to be interposed between the conductive coating and the printed circuit board, preventing the conductive coating from electrically contacting selected components and printed wiring board regions.

Abstract: An electrically continuous, grounded conformal EMI protective shield and methods for applying same directly to the surfaces of a printed circuit board. The EMI shield adheres and conforms to the surface of the components and printed wiring board. The shield takes the shape of the covered surfaces while adding little to the dimensions of the surfaces. The EMI shield includes low viscosity, high adherence conductive and dielectric coatings each of which can be applied in one or more layers using conventional spray techniques. The conductive coating prevents substantially all electromagnetic emissions generated by the shielded components from emanating beyond the conformal coating. The dielectric coating is initially applied to selected locations of the printed circuit board so as to be interposed between the conductive coating and the printed circuit board, preventing the conductive coating from electrically contacting selected components and printed wiring board regions.

Abstract: The degree of variation in the normalized site attenuation of an RF test chamber may be reduced by adjusting the properties of the RF absorbers lining the walls of the RF test chamber such that for the frequencies of greatest variation the ground screen formed by the conductive floor of the chamber appears to be much greater than its actual finite size. This may be done by progressively reducing the degree of chamber wall absorption (for the frequencies of interest) for locations on the walls closer to the floor. The reduction begins at a height above the floor equal to the height of the device under test above the floor, and proceeds to some maximum reduction in absorption at the level of the floor. The reduction in absorption has the effect of making the ground screen appear to be much larger than it really is, and may be obtained either by spacing the absorbing tiles apart by increasing amounts nearer to the floor, or by using less absorptive tiles closer to the floor, or both.