Design of a Miniature Directional Antenna for Geophysical Probing from Boreholes

Lytle, R.J.; Laine, E.F.

doi:10.1109/tge.1978.294588

Cited by 21 publications

(7 citation statements)

References 14 publications

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“…Most directional borehole radar tools are equipped with a pair of Adcock antennas or crossed magnetic-loop antennas ͑Lytle and Laine, 1978;Eisenburger et al, 1993;Eisenburger and Gundelach, 1999͒. Orthogonal data sets can be acquired from these types of array antenna systems, and directivity of the system can be achieved by signal processing, such that mechanical rotation of the antenna is unnecessary.…”

Section: Physical Limitations and Challengesmentioning

confidence: 99%

Surface and borehole ground-penetrating-radar developments

2010

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During the past 80 years, ground-penetrating radar ͑GPR͒ has evolved from a skeptically received glacier sounder to a full multicomponent 3D volume-imaging and characterization device. The tool can be calibrated to allow for quantitative estimates of physical properties such as water content. Because of its high resolution, GPR is a valuable tool for quantifying subsurface heterogeneity, and its ability to see nonmetallic and metallic objects makes it a useful mapping tool to detect, localize, and characterize buried objects. No tool solves all problems; so to determine whether GPR is appropriate for a given problem, studying the reasons for failure can provide an understanding of the basics, which in turn can help determine whether GPR is appropriate for a given problem. We discuss the specific aspects of borehole radar and describe recent developments to become more sensitive to orientation and to exploit the supplementary information in different components in polarimetric uses of radar data. Multicomponent GPR data contain more diverse geometric information than single-channel data, and this is exploited in developed dedicated imaging algorithms. The evolution of these imaging schemes is discussed for ground-coupled and air-coupled antennas. For air-coupled antennas, the measured radiated wavefield can be used as the basis for the wavefield extrapolator in linearinversion schemes with an imaging condition, which eliminates the source-time function and corrects for the measured radiation pattern. A handheld GPR system coupled with a metal detector is ready for routine use in mine fields. Recent advances in modeling, tomography, and full-waveform inversion, as well as Green's function extraction through correlation and deconvolution, show much promise in this field.

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Section: Physical Limitations and Challengesmentioning

confidence: 99%

Surface and borehole ground-penetrating-radar developments

2010

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“…Assume that both the transmitting and the receiving antennas are vertical half-wave electric dipoles. Lytle & Laine (1978) have designed a compact directional electric dipole antenna for boreholes that could be useful here. It uses a small eccentric dipole in a cylinder of a dielectric whose permittivity is about 8000 (see King & Smith 1981).…”

Section: The Electric Field At T H E Receiving Antennamentioning

confidence: 99%

Mapping subsurface fractures by radio-frequency holography: a simulation

Lorrain

1991

Geophysical Journal International

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SUMMARY A computer simulation shows that radio‐frequency holography could probably be used for mapping fractures in otherwise fairly homogeneous low‐conductivity rock or salt. According to in situ measurements of the attenuation of electromagnetic waves in a variety of media, and according to our simulation, it should be possible to image fractures up to distances of 150 or 200 m, with a good resolution. One application is the selection of sites suitable for the storage of radioactive waste. Another is the prediction of earthquakes. Our simulation involves image reconstruction by Fourier optics, from noisy synthetic data that we assume to be taken down a single deep borehole. The computer code is available from the author.

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“…There are few BHRs designed for forward-looking along the borehole axis (Miwa et al, 1999;Murray et al, 2000;Mancorda et al, 2009;Mason 2010) due to limitations of possible borehole antennae geometry imposed by the borehole dimension. The majority of current BHRs are designed for side-looking along the borehole radial with a dipole antenna (Lytle and Laine, 1978;Sato and Thierbach, 1991;Ellefsen and Wright, 2005).…”

Section: Introductionmentioning

confidence: 99%