Читать книгу Electromagnetic Simulation Using the FDTD Method with Python - Dennis M. Sullivan - Страница 25

When a plane wave traveling in medium 1 strikes medium 2, the fraction that is reflected is given by the reflection coefficient Γ, and the fraction that is transmitted into medium 2 is given by the transmission coefficient τ. These are determined by the intrinsic impedances η₁ and η₂ of the respective media (6):

(1.A.1)

(1.A.2)

The impedances are given by

(1.A.3)

The complex relative dielectric constant is given by

For the case where μ = μ₀, Eq. (1.A.1) and Eq. (1.A.2) become

(1.A.4)

(1.A.5)

The amplitude of an electric field propagating in the positive z direction in a lossy dielectric medium is given by

where E₀ is the amplitude at z = 0. The wave number k is determined by

(1.A.6)