# Question on phasors at boundary of oblique incidence.

1. Jun 2, 2013

### yungman

A plane wave travels in $\hat k_I=\hat x \sin\theta_I+\hat z \cos \theta_I$ direction hitting a boundary formed by xy plane ( z=0). The incidence wave is in the plane of incident formed by xz plane where y=0.

We let $\tilde E_I(\vec k_I)= \hat x E_{I_x}+\hat y E_{I_y}+\hat z E_{I_z} =E_{0I}e^{-j\vec k_I\cdot \vec r}$. This means $\tilde E_{0I}$ has to have x, y and z components $\Rightarrow\;\tilde E_{0I}=\hat x E_{0I_x}+\hat y E_{0I_y}+\hat z E_{0I_z}$

But at $z=0$, $E_{0I_z}$ has to be zero!
If we let $E_{0I_z}=0$, then it won't work for the vector where z is not 0! how do I resolve this? Only way I can think of is $E_{0I_z}$ is a function of z and it's zero at z=0. Am I right?

thanks

Last edited: Jun 2, 2013
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