| 摘要 |
A structural material is provided with a surface having a selected pattern of indentations which disperse a radar beam on reflection therefrom so that the radar signal returned to the radar apparatus has an intensity less than 0.1% of the signal reflected from a smooth surface. The material is covered with a plurality of closely spaced indentations and/or raised portions in a random or systematic pattern having a depth or height or a radius of curvature in the range from about 0.2 to about 5.0 times the length of the waves used for normal radar detection of distant objects, e.g. airplanes, missiles, etc. Radar wave lengths are typically in the range from several millimeters to several hundred millimeters. The indentations or raised portions vary in depth or radius of curvature within the stated range and are variably positioned on the surface. A radar signal reflected from a properly constructed surface of this pattern is 99.995% less than a radar signal reflected from a smooth surface. For aerodynamic applications, the cross-section of the indentations and/or raised portions should be configured to provide aerodynamic efficiency in the direction of air flow over the surface in normal use.
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