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BELL SYSTEM TECHNICAL JOURNAL 



of Part II are directly applicable and the reflection coefficient depends 

 upon the ratio of the intrinsic impedances of the media. 



A more interesting situation arises when the incidence is oblique. 

 Let the x3;-plane be the boundary between two homogeneous media 

 and let the electric vector he parallel to this boundary. We may assume 

 it to be parallel to the :x;-axis. In this case the electric field strength 

 is given by 



E, = £oe-"+^"S Ey = E, = 0, (20) 



where Eo is the amplitude and 5 is the distance from the equiphase 

 surface passing through the origin. If the angle of incidence is ?? 

 (Fig. 5), this distance may be expressed as: s = y sm § -\- z cos??. 



Fig. 5 — Reflection of plane waves. The :x:-axis is toward the reader, the xy- 

 plane is the boundary between the media, the £-vector is toward the reader, the 

 angle of incidence = i}, and the angle of reflection = xp. 



The magnetic vector is perpendicular to E and to the ray and its 

 value is 



H = Hoe-<''+^"', £o = vHo. (21) 



The cartesian components are then 



Hy = Ho cos ?? 6-"'+^^, Hz ^ - Ho sin ?? e-'"+'"\ H^ = 0. 



Equations (20) and (21) represent the motion of equiphase planes 

 in the direction specified by the angle §. It is equally possible to 

 regard them as representing the motion of phase-amplitude patterns 



