Determine the polarity of the reflected EM wave.

[yungman]

Attached are the drawings. Does the polarity Eof depend on $\Gamma =\frac {\eta_2-\eta_1}{\eta_2+\eta_1}$

So if $\eta_2<\eta_1$, the Γ is negative and the polarity of the reflected wave is opposite polarity?

I understand $\theta_i=\theta_r$ and all that. As shown in the drawing, if you look at the TEM wave travel from the left at z=-ve, in medium 1, hitting the boundary on xy plane at z=0, say it is perpendicular polarization where $\vec {E}= \hat {y} E(z)$, which is parallel to the boundary. If $\eta 1 > \eta 2\;\Rightarrow\; \Gamma=-ve$, is $\vec {E}_r$ in opposite direction...$\vec {E}_r=-\hat {y} E_r$ as in the upper left drawing.

And if $\eta 2 > \eta 1\;\Rightarrow\; \Gamma = +ve$, then $\vec {E}_r=\hat{y}E_r$. This is shown in the upper right drawing.

The upper left shows $\eta 1 > \eta 2$ where Ei and Er are pointing in y direction. In drawing on top right where $\eta 1 < \eta 2$, Er is in -ve y direction.

I drew the case where Ei is on the xz plane as shown in lower left drawing, how do I even determine the direction of the reflection based on the intrinsic impedance of the two media? Please help. Please provide some article links if you can.

Thanks

Alan

 

[Vailanor]

Yes, the polarity of the reflected wave will depend on \Gamma. If \eta_2<\eta_1, then the Γ is negative and the polarity of the reflected wave will be opposite to the incident wave. This can be seen in the lower left drawing; the incident wave is traveling along the xz plane and the reflected wave will travel in the opposite direction (i.e., -ve x direction). For more information, please refer to this article: https://www.researchgate.net/public..._an_interface_between_two_uniform_dielectrics