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ASTM D4935-99

Заменен
Standard Test Method for Measuring the Electromagnetic Shielding Effectiveness of Planar Materials (Withdrawn 2005) — 10 стр.
Причина отмены

This test method covers a procedure for measuring the electromagnetic (EM) shielding effectiveness (SE) of a planar material due to a plane-wave, far-field EM wave. From the measured data, near-field SE values may be calculated for magnetic (H) sources for electrically thin specimens. Electric (E) field SE values may also be calculated from this same far-field data, but their validity and applicability have not been established.

Formerly under the jurisdiction of Committee D09 on Electrical and Electronic Insulating Materials, this test method was withdrawn in September 2005. This test method was withdrawn without replacement since Committee D09 cannot maintain a standard for which the expertise may not lie within the current committee membership, or for which the utilization of the standard is questionable.

Область применения

1.1 This test method provides a procedure for measuring the electromagnetic (EM) shielding effectiveness (SE) of a planar material due to a plane-wave, far-field EM wave. From the measured data, near-field SE values may be calculated for magnetic (H) sources for electrically thin specimens. Electric (E) field SE values may also be calculated from this same far-field data, but their validity and applicability have not been established.

1.2 The measurement method is valid over a frequency range of 30 MHz to 1.5 GHz. These limits are not exact, but are based on decreasing displacement current due to decreased capacitive coupling at lower frequencies and on overmoding (excitation of modes other than the transverse electromagnetic mode (TEM)) at higher frequencies for the size of specimen holder described in this test method. Any number of discrete frequencies may be selected within this range. For electrically thin, isotropic materials with frequency-independent electrical properties of conductivity, permittivity and permeability, measurements may be needed at only a few frequencies as the far-field SE values will be independent of frequency. If the material is not electrically thin or if any of the parameters vary with frequency, measurements should be made at many frequencies within the band of interest.

1.3 This test method is not applicable to cables or connectors.

1.4 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

ICS
17.220.20 Measurement. Including measuring instruments, instrument transformers / Измерения электрических и магнитных величин. Включая измерительные приборы, измерительные трансформаторы
Сборник ASTM
10.02 Electrical Insulation (II): D2519–latest / Электрическая изоляция (II): с D2518 и далее
Тематика
Electrical Insulating Materials