EM wave reflectn from dielectrric

[koushikr_in]

if an right circularly polarised em wave is incident on a dielectric , what is the poln of reflected wave?

what will be the case if dielec replaced by metal?

 

[RFSimulator]

Hi,

The wave will change the polarization depending on the angel of incident.

Check for Fresnel equations in any optics book.

F.

 

[DJ]

You have a magnetic wall.

D.J

 

[koushikr_in]

what is meant by magnetic wall?

 

[wlcsp]

The circularly polarized wave will still be circular, the phase will change, though. When it hits metal (non perfect metal), depends on the skin depth, it can penetrate the metal when the metal is thinner compared to the skin depth. When it perfect metal, then dirichlet boundary condition applies where all tangential electric field is zero and normal magnetic field is zero.

 

[sergio mariotti]

I Agree thit RFSimulator that the magnitude of reflected wave depend on the incident angle and the ratio n1/n2.

The sense of polarization is opposite (if you send RHCP, the echo is LHCP).

Pay attention! The number of reflection planes are often 2, as for transmission lines, the reflections occur at the discontinuity, you'll find a discontinuity at the input AND at the output of the line.

 

[baluba]

well, i believe things are a bit more complicated; a circularly polarized incident wave can be decomposed in 's' and 'p' polarized waves with equal amplitudes; each of these components will undergo a different reflection at a dielectric interface (see Fresnel formulas), so after reflection the 's' and 'p' components will have different amplitudes and this will give an elliptical polarization;

when you have a perfect metal the reflected wave will be circularly polarized.

correct me if i'm wrong :roll: [/b]

 

[sergio mariotti]

Dear baluba, you are right.
effectively i've confused the original question asked by koushikr_in.
In any case, an observer equipped with a circular polarized TX and a double circular pol. RX, will observe an echo with a dominant opposite polarization.
This agree the theory on baluba's post