Reflection and transmission coefficients

Reflection and transmission coefficients

When an electromagnetic wave passes from a medium of permeability μ₁ and dielectric constant ε₁ to one with values μ₂ and ε₂, part of the wave is reflected at the boundary and part transmitted. The ratios of the amplitudes in the reflected wave and the transmitted wave to that in the incident wave are called the reflection and transmission coefficients, respectively. For oblique incidence, the reflection and refraction formulas of optics are most convenient, but for normal incidence of plane waves on plane boundaries, such as occur with transmission lines, waveguides, and some free waves, the concept of wave impedance and characteristic impedance is useful. See Electromagnetic radiation