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# Fresnel coefficients

## Fresnel coefficients

(OP)
For a wave travelling from a denser medium (e1=11.7) into air (e2=1), the reflection (R) and transmission (T) coefficients seems to be a positive value for R and thus T is bigger than 1 for both parallel and perpendicular polarization. How can this be? Do I need to change the formulas accordingly since e1>e2?

### RE: Fresnel coefficients

Even though the transmission coefficient is higher than unity for cases when e1>e2, the power that goes trough the interface can not be more than the power of the incident wave. If the electric field component of the transmitted wave is bigger than that of the incident wave then the opposite is true for the magnetic field component. The wave impedance that is different for materials with different permittivity is defined as square root of the ratio between permeability and permittivity. The wave impedance tells the ratio between the electric and magnetic components of the wave. This ratio is different in different materials.

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