under sinusoidal conditions in a medium where the phasors D, E and J representing respectively the electric flux density, the electric field strength and the electric current density are linearly related, complex quantity εre defined by the relation
where γ is the conductivity of the medium, ω the angular frequency and ε0 the electric constant
NOTE 1 – The effective complex relative permittivity is generally frequency dependent. For an isotropic medium the effective complex relative permittivity is a scalar; for an anisotropic medium it is a tensor.
NOTE 2 – The effective complex relative permittivity and the complex relative permittivity εr are linked by the relation
In a conductive medium, including good conductors and imperfect dielectrics, the useful and measurable quantity is the effective complex relative permittivity.
NOTE 3 – The negative of the imaginary part of the effective complex relative permittivity represents both dielectric losses and losses due to the conductivity, the part due to conductivity being represented by γ/ε0ω.
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