Shielding materials are shown in Table 1 below. Some materials work better than others for shielding at certain frequencies due to materials property regarding its absorption loss and its reflection loss. There are two types of material classifications regarding shielding effectiveness / shielding: 1) ferrous and 2) non-ferrous. The concept is as simple as this: a ferrous material is one which does include some trace amounts of iron (ferrite) whereas a non-ferrous material is one that does not.
|Mumetal (at 1 kHz)||900||0.000001|
|Superpermalloy (at 1 kHz)||3000||0.0000003|
The trend is the smaller the Reflection Loss the better the material for shielding effectiveness, and the larger the absorption loss the better the material for shielding effectiveness. The tabular data also indicate that reflection loss is the primary contributor to shielding effectiveness at low frequencies for either ferrous or non-ferrous shielding materials.
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