System and method for filtering electromagnetic transmissions
AssigneesASTIC Signals Defenses L.L.C., CPFilms Inc.
InventorsDeron Simpson, Lisa Y. Winckler
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Abstract
A combination of filters for filtering selected wavelengths of electromagnetic radiation is provided on a transparent substrate such as a plastic film or glazing of a window. The combination of filters prevents or attenuates the passage of wavelengths through the substrate into a building, where the passage of the wavelengths into the building could adversely affect people or machinery within the building. The combination of filters is useful improve wireless networks performance by blocking or attenuating undesired electromagnetic interference, and radio frequency interference.
Claims28
A method for preventing or attenuating the passage of unwanted electromagnetic wavelengths into an enclosure, the enclosure comprising at least one transparent area comprising a transparent substrate, the method comprising the step of applying a combination of filters to said substrate, said combination of filters comprising a first light filter and a second light filter which screens UV light, wherein said first light filter is:
- a light filter (a) comprising a heat reflecting layer and an electrically conductive metal layer, or a light filter (b) having an IR transmission at wavelengths between 780 nm and 2500 nm of no more than 50%, or a light filter (c) which has a sheet resistance of less than 4 ohms per square and comprises a sequence of layers:
- dielectric layer/IR reflecting metal layer/dielectric layer;
- or IR reflecting metal layer/dielectric layer/IR reflecting metal layer, wherein said sequence of layers is coated onto said substrate or onto a transparent plastic sheet;
- said combination of filters being configured to prevent or attenuate the passage of said electromagnetic wavelengths through said apparatus and said dielectric of each dielectric layer has an index of refraction in the range of about 1.35 to 2.6.
Dependencies are inferred from the claim text.