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BELL SYSTEM TECIIX/CAL JOURNAL 



den change in dielectric constant.'" Similar reflections may theoretically 

 take place also at an interface where the permeability of the medium 

 changes suddenly. The case in which there is a change of conductivity has 

 an important bearing on waveguide transmission. It will therefore be dis- 

 cussed in considerable detail. 



Assume a plane wave incident obliquely upon a conducting surface as 

 shown in Fig. 6.4-1. The line along which the wave is progressing (wave- 

 normal) is referred to as the incident ray. It intersects the conducting 

 surface or interface at a point and makes an angle d with the perpendicu- 

 lar OZ. After reflection, the normal to the new^ wave wave front makes an 

 angle 6' with the perpendicular OZ. This second wave-normal is known as the 



Fig. 6.4-1. Reflection at oblique incidence from a metal plate for the particular case where 

 the electric vector is perpendicular to the plane of incidence. 



reflected ray, and its angle with the perpendicular OZ is known as the angle 

 of reflection. The plane containing the incident ray and the perpendicular 

 OZ is known as the plane of incidence. The incident and reflected rays lie 

 in the same plane, and their corresponding angles of incidence and reflection 

 are numerically equal. 



In problems of oblique incidence there are two cases of interest, depend- 

 ing on whether the electric or the magnetic comi)onent lies in the plane of 

 incidence. For our particular j)urpose, the second of these two cases is of 

 special interest and it will therefore be discussed in considerable detail. 

 The vector relations corresj)onding to this case are shown in Fig. 6.4-1. 



'^ For a more general discussion of the electromagnetic thcor\- of retlectioii: L. Page 

 and N. 1. Adams, "Princii)lcs of I'.lectricity," 1). \'an Xostrand Co., Inc., pp 569-575, 

 New York 1931. R. I. Sarhacher and \V. A. I'-dson, "Hyper and Ultra-high Fretiuency 

 Engineering," John \\ ilcy & Sons, Inc., i)p 105-116, New York 1943. 



