=== Ray Reflection & Transmission ===
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[[File:reflect.png|thumb|350px|The Incident, Reflected and Transmitted Rays at the Interface Between Two Dielectric Media]]
The incident, reflected and transmitted rays are each characterized by a triplet of unit vectors:
* <math>( \mathbf{ \hat{u}_{\|}', \hat{u}_{\perp}', \hat{k}' } )</math> representing the reflected parallel polarization vector, reflected perpendicular polarization vector and reflected propagation vector, respectively.
* <math>( \mathbf{ \hat{u}_{\|}'', \hat{u}_{\perp}'', \hat{k}'' } )</math> representing the transmitted parallel polarization vector, transmitted perpendicular polarization vector and transmitted propagation vector, respectively.
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[[File:reflect.png]]
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The Incident, Reflected and Transmitted Rays at the Interface Between Two Dielectric Media
The reflected ray is assumed to originate from a virtual image source point. The three triplets constitute three orthonormal basis systems. Below, it is assumed that the two dielectric media have permittivities ε<sub>1</sub> and ε<sub>2</sub>, and permeabilities μ<sub>1</sub> and μ<sub>2</sub>, respectively. A lossy medium with a conductivity σ can be modeled by a complex permittivity ε<sub>r</sub> = ε'<sub>r</sub> âjσ/ε<sub>0</sub>. Assuming '''n''' to be the unit normal to the interface plane between the two media, and Z<sub>0</sub> = 120Ω , the incident polarization vectors as well as all the reflected and transmitted vectors are found as: