# EM wave at a plane dielectric boundary

1. Jun 17, 2012

### erece

i was studying incidence of EM wave at a plane dielectric boundary and encountered equations
in the attachment . I just want to know if n2 > n1 then electric field amplitude at the boundary increases . So from where does this extra value comes ?
n1 and n2 are intrinsic impedances of 1st and 2nd medium

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2. Jun 18, 2012

### jegues

I think you've mixed up the wording a little here.

We are talking about an electromagnetic plane wave at a dielectric boundary.

The two equations you have in your figure are the reflection and transmission coefficients for an EM plane wave across two media. (i.e. media 1 having intrinsic impedance η1, media 2 having intrinsic impedance η2)

If they are dielectric media then they are lossless and we will see no decay or the wave as it travels through the mediums. (i.e. the attenuation constants are zero, α1 = 0, α2 = 0)

Why not write an expression for the electric field at the boundary and see if you can justify whether or not the amplitude will increase of decrease based on the values of η1 and η2.