How does radio wave get reflected? Actually recently I posted a question in h-bar ($\hbar$) relates to radio wave reflection from mirror, and one of the user replied that it can't, only ionosphere can reflect it, so my question what is the general phenomenon of different frequency em wave reflection? How does ionosphere able to reflect those wave? Do we see similar phenomenon when dealing with outer space? I am not a physicist so answering this question s in not in my reach although I tried some research but that does not yield Anything, any help will be appreciate d
 A: Radio wave is an electromagnetic wave, and can be reflected by a conducting media - a sheet of metal or plasma, like in the ionisphere.
What happens is that the electromagentic field of the wave induces currents in the conducting media, which generate the electromagentic wave propagating in the opposite direction, wheres deep inside into the media the field is completely screened. The depth of the electromagnetic wave penetration into a conducting media is known as skin depth.
Similar thing happens when a wave is incident onto a dielectric media, but in this case it is only partially reflected and partially transmitted into the media (i.e., not fully screened.)
The phenomenon is purely classical - $\hbar$ is not involved.
A: Those lecture notes are showing a derivation of the Hagen-Rubens formula describing an EM wave reflection coefficient from a conducting surface. The author is also giving an extensive comment on EM propagation in the ionosphere.
Please remember that radio waves are also reflected from metallic surfaces, after all, we have satellite dishes and their job is exactly to do that.
