the medium in which a variable electric field produces an electric current density vector whose magnitude in a given direction is small relative to that of the vector in a particular frequency band
NOTE 1 – For a sinusoidal wave in an isotropic medium, the medium is dielectric if the following relation is satisfied:
where is the relative real permittivity, ε0 is the electric constant, σ is the conductivity, ω is the angular frequency.
NOTE 2 – An anisotropic medium may be dielectric only in certain directions.
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