The effect of frequency on the accuracy of simple methods for calculating magnetic shielding of infinite planar shields

The accuracy of simple approximate methods used for calculating magnetic shielding of infinite planar shields is studied for a wide range of frequency spectrum (i.e. from 10 Hz to 1 /spl times/ 10/sup 6/ Hz). Testing against exact integral solution results gives the frequency band where simple formulas can be applied as a useful simple tool for magnetic shielding calculations.