Title :
Analysis of a borehole radar in cross-hole mode
Author :
Sato, Motoyuki ; Thierbach, Rudolf
Author_Institution :
Dept. of Resources-Eng., Tohoku Univ., Sendai, Japan
fDate :
11/1/1991 12:00:00 AM
Abstract :
A theoretical approach to cross-hole radar measurements is presented. An approximate analytical form for the current distribution on an antenna in a borehole is derived, and the theoretical receiving signal of the borehole radar in the cross-hole measurement is calculated. Theory is compared in the time-domain with the measured borehole radar signal obtained in a salt deposit. The radiation pattern of a borehole radar excited by a pulse is discussed. The accuracy of tomographic analysis, which is often applied to cross-hole radar measurements, is strongly governed by this radiation pattern. It is found that, in practice, most borehole radars have a pattern of a λ/2 dipole antenna. However, the radiation pattern can be deformed by short pulse excitation, loading by the surrounding media, and coupling to the logging cable
Keywords :
antenna radiation patterns; geophysical techniques; radar antennas; radar applications; radar theory; remote sensing by radar; time-domain analysis; antenna; borehole radar; coupling; cross-hole mode; current distribution; geophysical technique; loading; logging cable; radiation pattern; remote sensing; salt deposit; short pulse excitation; theoretical receiving signal; time-domain; tomographic analysis; Antenna measurements; Antenna radiation patterns; Antenna theory; Current distribution; Current measurement; Radar antennas; Radar measurements; Radar theory; Receiving antennas; Signal analysis;
Journal_Title :
Geoscience and Remote Sensing, IEEE Transactions on