Hello everyone!
I have 2 questions about polarization, first one is:
There is a wall of the building and the beam with line polarization.
What we will see in backscattering? Which polarization? Circle(chaotic) or old one will dominant?
How it depends on the distance, say 100m?
The second question is the same, but this time I'm interesting about Mie scattering:
say we have a rain, so what will be with polarization, by propagation through distance, polarization will becoming more chaotic->circle?
It doesn't depend on distance.
If the surface is randomly rough compared to a wavelength, over distances less than a wavelength, then polarization will be scrambled.
For flat surfaces polarization is not scrambled but what happens depends on the angle of incidence, the material of the wall (different for glass compared to metal) and direction of linear polarization relative to the plane of reflection. See the Feynman Lectures above - I started trying to explain it here and gave up - it is quite complicated.
Rain doesn't scramble polarization much. Circular polarization is used to avoid seeing rain because the reflection from raindrops (which are fairly symmetrical) is still mainly circularly polarized but in the opposite rotation direction to some of the reflections from aircraft (e.g. from double bounces and non-symmetrical shapes) so the two can be separated by the receiver. Rain reflects linear polarization with the same orientation in space as it started with, as described by Mie scattering. (This is true for reflection back in the direction it came from).
Of course, scattering has an influence on polarization. In a simple case, one can see the effect using standard formula for the reflection coefficient (see, e.g., reference below)
http://listid.ru/item/1433119.html
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