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Bohling, Geoffrey C. / A ground penetrating radar study of water table elevation in a portion of Wisconsin's central sand plain

[DNR-050] (1988)

III. Radar theory and hydrogeological applications, pp. 19-32 PDF (3.7 MB)

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21 tromagnetic energy) the above parameters appear in the following combi- nations: ce =-- +we' (4) and e C-E - (5) w where w is the angular frequency of the electrical field. The parameters defined in equations 4 and 5 are called the real effective conductivity and the real effective permittivity, respectively. The relative real effective per- mittivity, Ee r, is defined such that Ee -eTCO. (6) In the following discussion the term " dielectric constant" refers to Ee C. Signal Propagation Velocity In most practical applications, the GPR signal can be considered to be a wave packet moving at a velocity of C V = e(7) where c = the velocity of light in a vacuum (about 1 ft/ns) (Annan and Davis, 1976; Shih et al., 1986; Ulriksen, 1982; Houck, 1984; Wright et al., 1984; Bogorodsky et al., 1985). Over the range of frequencies of commer- cially available GPR units, d ' of earth materials is essentially equal to zero, so that Ee r is approximately equal to the real part of the relative

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