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A Note on the Groundwave Phase Velocity Over a Plane Earth
Author(s) -
Segal B.
Publication year - 1968
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1002/rds196834397
Subject(s) - phase velocity , plane (geometry) , phase (matter) , group velocity , physics , capacitive sensing , surface (topology) , space (punctuation) , earth (classical element) , free space , constant (computer programming) , classical mechanics , mathematical analysis , optics , mathematics , geometry , philosophy , mathematical physics , quantum mechanics , linguistics , computer science , programming language , operating system
Equations are derived for the phase velocity of an electromagnetic groundwave propagating over a plane earth having a constant surface impedance. The equations are found to differ in essence from one previously derived by King and Schlak (1967). As a result of the interpretation made here, it is concluded that the local phase velocity over a highly inductive surface exceeds the velocity of light in free space under certain conditions. For strongly capacitive surfaces, the phase velocity is expected to exceed the velocity in free space at all distances. (At the end of this Note, R. J. King and G. A. Schlak provide a reply to the criticisms. Ed.)