Electromagnetic shielding behavior of wire-mesh screens

The electromagnetic shielding behavior of bounded-junction wire-mesh screens is discussed in the frequency range where the individual meshes are electrically small. The screen, whose meshes are assumed to be square, is described by a equivalent sheet impedance operator. The plane-wave shielding effectiveness of a planar-mesh screen is derived. The problem of coupling between antennas on either side of the planar mesh is addressed, and its applicability to the measurement of mesh properties is described. The low-frequency electric and magnetic shielding afforded by mesh enclosures is considered. Because of the reactive character of the mesh surface, the plane-wave shielding effectiveness decreases with increasing frequency. The enclosure's magnetic-field shielding effectiveness increases with increasing frequency, but saturates at a maximum value that depends on the geometry of the enclosure, the mesh size, and the mesh wire radius. The enclosure electrostatic-field shielding effectiveness depends only on the enclosure and mesh geometries.<
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