GROUND RETURN PARAMETERS OF TRANSMISSION LINES - AN ASYMPTOTIC ANALYSIS FOR VERY HIGH FREQUENCIES.

Wave propagation with ground return is studied in the classical literature, by J. R. Carson and others, for frequencies up to a critical upper limit, where displacement currents in the earth start becoming predominant. This paper derives simple expressions for the additional ground impedances, valid in the supercricital range. Problems when these are relevant are indicated. The new equations, when applied to the high frequency Carson range, show perfect coincidence with Carson's equations. It appears that, at very high frequencies, the penetration depth remains finite, the earth resistance is also finite, while the earth reactance becomes zero.