Epstein, Paul S. (1947) Radio-wave propagation and electromagnetic surface waves. Proceedings of the National Academy of Sciences of the United States of America, 33 (6). pp. 195-199. ISSN 0027-8424. http://resolver.caltech.edu/CaltechAUTHORS:EPSpnas47
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A Discrepancy and Its Resolution. - The problem of the propagation of radio-waves along the surface of the (plane) earth was first treated in a celebrated paper by A. Sommerfeld (1909).(1) Let the (r, φ)-plane of a cylindric system of coordinates coincide with the plane of the earth surface and let the z-axis point vertically upward. Sommerfeld considered a vertically oscillating dipole (radio-antenna) in the air, close to the origin (z = 0, r = 0) and asked what secondary waves were produced by the discontinuity due to the presence of the partially conducting earth. His investigation led to the result that the Hertzian vector II describing the electromagnetic field can be divided, in either medium (air and earth), into two parts: II = Q + P, where the part Q has the character of space-waves, which at large distances from the origin are proportional to R^-1, if R = (r^2 + z^2)^1/2. On the other hand, P is a surface-wave: at large distances it becomes proportional to r^-1/2 and is restricted to the vicinity of the earth surface.
|Additional Information:||© 1947 by the National Academy of Sciences. Communicated March 31, 1947.|
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|Deposited By:||Tony Diaz|
|Deposited On:||21 Mar 2007|
|Last Modified:||14 Nov 2014 19:19|
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