| 摘要 |
A metallized plastic RFI/EMI shield is provided against electromagnetic energy for a circuit card wherein the shield is formed of a box enclosure with two casing halves to enclose the card, the first casing half having a solid flange side walls surrounding the card and the second casing half having a flange formed by flat, plate-like closely-spaced fingers, the fingers confronting, being in electrical contact with and mating in full length with substantially the entire periphery of the side walls of the first casing half. The fingers are preferably spaced with a separation of less than +E,fra 1/4+EE wavelength of any measurable harmonic of the intended operating frequency, typically up to the tenth harmonic. A slot may be provided to receive the fingers on the outside of the side walls, and closely-spaced grounding pins arranged around the periphery of the card may extend between the first and second casing halves through ground plated perforations along the edge of the side walls.
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