Displacement of an electromagnetic beam upon external dielectric reflection

Abstract

The sideways displacement of an electromagnetic beam upon external reflection from a dielectric has been investigated. The experimental results, using 3 cm microwaves, are compared to those predicted by a theory based on a plane wave approach. The experiment has been completed for both perpendicular and parallel polarization as a function of total propagation distance at several angles of incidence around 45°.

Displacement of a microwave beam upon transmission through a dielectric slab

“…For some thicknesses, the beam shift is in the negative or backwards direction, especially for the larger incident angles. This should not be surprising since such beam shifts were ~redicted and observed for the reflection of a similar microwave beam from a semi-infinite dielectric, as reported previously (5).…”

“…The composition of the incident microwave beam Because the agreement between theoretical and has been discussed in previous publications (5,6) experimental values has always been acceptable we and is presented here in a similar form. Others, felt that a study of the beam position upon trans-including Antar (7), have used a similar approach, mission through a dielectric slab would yield useful but the emphasis here is naturally on that of a information.…”

“…It is also legitimate to assume that for each plane wave or eigenwave the aperture is an infinite slit of width equal to the actual horn width. This simplifying assumption has been used before by Bezner (8) and Read and co-workers (5). Thus, a t the aperture, z = 0, the y-component of the electric field may be written as…”

“…Briefly, we have previously examined microwave beam with a width of several wavelengths total internal reflection (Goos-Hanchen effect) (I), which is considerably less than the optical beam external reflection from a semi-infinite dielectric suggested by Antar. The basis of the beam construcmedium (5), and most recently, reflection from a thin tion is to consider it as a summation or superposition dielectric slab (6). The work described in detail of infinite plane waves grouped around the central below, then, is a logical and important extension of eigenwave.…”

Nonspecular shifts of microwaves in partial reflection

“…Fig. 4 -Experimental set-up to study the angular shift in a two-step procedure in complete analogy to the procedure used in [24,25] to study the external reflection process. It turned out here that it was completely sufficient to change the distance between the receiving horn antenna and the prism only once.…”