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Plane wave reflection and transmission. Reflection of uniform plane waves at normal incidence. Boundary conditions. (at the interface, z =0). Reflection from perfect electric conductor. (at the interface, z =0). Example. Wave reflection from multiple interfaces. Example : radome.
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Boundary conditions (at the interface, z =0)
Reflection from perfect electric conductor (at the interface, z =0)
Example : radome Reflection Transmission
Example : anti-reflection coating Calculate the refractive index and minimum thickness for the glass coating to provide total transmission from air to the glass at a free space wavelength of 570nm. refractive index of the glass is n3=1.45. (n: refractive index)
If an EM wave approaches a surface obliquely, it is easier to decompose the field into two components, s-polarization and p-polarization. s-polarization (perpendicular) p-polarization (parallel)
Wave propagation TV antenna TV signal transmitting antenna TV signals are transmitted as EM wave with horizontal polarization.
Polarization of EM waves Source current Source current
Reflection from ground and troposphere EM waves undergo reflections and diffractions while propagating toward receivers.
2-Ray Ground Reflection T R ht hr Phase shift! • For d>> hr, ht, • low angle of incidence allows the earth to act as a reflector • the reflected signal is 180 out of phase • Pr 1/d4 d