Determine the polarity of the reflected EM wave.

[Alan0354]

I want to verify the polarity of the reflected EM wave on the boundary compare to the incident. This include even if the incident wave is not NORMAL incident.

Does the polarity depends 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?

 

[tuncay]

Yes, that equation is true for normal incidence. if it is negative, E-field vector of reflected wave is in the opposite direction of E-field vector of incident wave, right at the boundary.

 

[Alan0354]

Thanks for the reply, but how about non normal incidence. I understand \[\theta_i=\theta_r\] and all that. But 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........\[\vec {E}_r=-\hat {y} E_r\]

And if \[\eta 2 > \eta 1\;\Rightarrow\; \Gamma = +ve\], then \[ \vec {E}_r=\hat{y}E_r\].

Attached is the drawings. 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 the low 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

 

[tuncay]

Here is an article that is describing the reflection mechanisms:
https://pcwww.liv.ac.uk/~awolski/Teaching/Liverpool/PHYS370/AdvancedElectromagnetism-Part4.pdf
A good book including this topic is Advanced Engineering Electromagnetics by Balanis.

 

[Alan0354]

Thanks, I have to read into this, looks like page 42 talk about it, but I need to read more, it's New Year today and I am in a lazy mood!!!