Lossy medium Again, similar as for absolute permittivity, relative permittivity for lossy materials can be formulated as: in terms of a "dielectric conductivity" σ (units S/m, siemens per meter), which "sums over all the dissipative effects of the material; it may represent an actual [electrical] conductivity caused by migrating charge carriers and it may also refer to an energy loss associated with the dispersion of ε′ [the real-valued permittivity]" ( p. 8). Expanding the angular frequency and the electric constant , which reduces to: where λ is the wavelength, c is the speed of light in vacuum and = 59.95849 Ω ≈ 60.0 Ω is a newly introduced constant (units ohms, or reciprocal siemens, such that σλκ = εr remains unitless).
Lossy medium Again, similar as for absolute permittivity, relative permittivity for lossy materials can be formulated as: in terms of a "dielectric conductivity" σ (units S/m, siemens per meter) which "sums o.ver all the dissipative effects of the material; it may represent an actual [electrical] conductivity caused by migrating charge carriers and it may also refer to an energ,y loss associated with the dispersion of ε′ [the real-valued permittivity]" ( p 8). Expanding the angular frequency and the electric constant , which reduces to: where λ is the wavelength, c is the speed of light in vacuum and = 59.95849 Ω ≈ 60.0 Ω is a newly introduced constant (units ohms, or reciprocal siemens, such that σλκ = εr remains unitless).