WAVE LENGTH LENSES.
Author: Gilbert Wilkes
Publisher:
Published: 1947
Total Pages: 49
ISBN-13:
DOWNLOAD EBOOKThe property shown by dielectric blocks of concentrating the energy of electromagnetic waves is similar in many respects to the operation of an ordinary glass optical lens. The energies considered have a much lower frequency than that of light, and the wave lengths are generally such that the lenses have dimensions of the order of a wave length, for the more usual applications. In this they differ radically from optical lenses. A definite phase relationship is found to exist between the energy in the lens and that of free space, and if in the design of the lens, this relationship is not respected, the lens will not yield its maximum concentrating power, or gain. The energy velocity in a lens approaches that of light with a decreasing cross section. The side walls of a lens are found to be effective energy gatherers. The thinner the lens the longer it can be made so as to increase its exposed area. An increased gain results. The index of refraction of the lens material plays a role in this action by its effect on the lens velocity. Experimental data correlating their different properties are given x7 (Author).
