Progress In Electromagnetics Research B
ISSN: 1937-6472
Home | Search | Notification | Authors | Submission | PIERS Home | EM Academy
Home > Vol. 28 > pp. 253-271


By A. J. Sangster, S. Lavu, R. McHugh, and R. Westerman

Full Article PDF (532 KB)

Recent research into very large, regularly shaped, geological structures has shown that in the 100 kHz to 10 MHz frequency range electromagnetic waveguide behaviour is observed when the material forming the structure is not too lossy (conductivity σ<0.0001). While mode formation and modal behaviour in electromagnetic waveguides is very well understood, much of the literature describes high frequency structures for which it can generally be assumed that the loss tangent of the wave guiding medium (tanδ) is very much less than unity. In this case wave attenuation is small and can generally be considered to be insignificant. This is not true for large low frequency waveguides, such as those formed by geological strata, and little seems to have been reported in the literature on the nature of modes in waveguides of this description. The paper takes the form of a parametric study aimed at ascertaining the limitations to modal formation in waveguides, for which tand is greater than unity, by revisiting the basic equations describing electromagnetic wave propagation in lossy media. The theoretical predictions are supported by modelling studies on large waveguide strata formed from material layers with dimensions typical of a geological structure such as a coal seam or oil-wet, strata-bound, petroleum reservoir.

A. J. Sangster, S. Lavu, R. McHugh, and R. Westerman, "Electromagnetic Moding in Lossy Geological Strata," Progress In Electromagnetics Research B, Vol. 28, 253-271, 2011.

1. Wait, J. R., "The possibility of guided electromagnetic waves in the earth's crust ," IEEE Transactions on Antennas and Propagation, Vol. 1, No. 3, May 1963.

2. Emslie, A. G. and R. L. Lagace, "Propagation of low and medium frequency radio waves in a coal-seam," Radio Sci., Vol. 11, 253-261, 1976.

3. Cory, T. S., "Wireless radio transmission at medium frequencies in underground coal mines," Electromag. Guided Waves in Mine Environments, Boulder, Co., 1978.

4. Hill, D. A., "Electromagnetic propagation in an asymmetrical coal seam," IEEE Transactions on Antennas and Propagation, Vol. 34, No. 2, 244-247, 1986.

5. Stolarczyk, L. G., "Electromagnetic seam wave mapping of roof rock conditions across a long-wall panel," 18th Int. Conf. on Ground Control in Mining, West Virginia University Morgantown, WV, USA, Aug. 3-5, 1999.

6. Ansoft Corporation, "High Frequency Structure Simulator,".

7. Sentman, D. D., "Schumann resonance effects of electrical conductivity perturbations in an exponential atmospheric/ionospheric profile," J. Atmos. Terr. Phys., Vol. 45, No. 1, 55-65, 1983.

8. Simpson, J. J. and A. Taflove, "A review of progress in FDTD Maxwell's equations modeling of impulse subionospheric propagation below 300 kHz," IEEE Transactions on Antennas and Propagation, Vol. 55, No. 6, 1582-1590, 2007.

9. Mosiane, M. E., Propagation in a dielectric slab, Thesis, University of Cape Town, 2008.

10. Scott, D. F. and T. J. Williams, "Investigation of electromagnetic emissions in a deep underground mine," www.cdc.gov/niosh/mining/pubs/pdfs/ioeei.pdf, 2004.

11. Frid, V., "Electromagnetic radiation method for rock and gas outburst forecast," J. of Applied Geophysics, Vol. 38, 97-104, 1997.

12. Frid, V., "Calculation of electromagnetic radiation criterion for rockburst hazard forecast in coal mines," Pure and Applied Geophysics, Vol. 158, 931-944, 2001.

13. Frid, V., D. Bahat, J. Goldbaum, and A. Rabinovitch, "Experimental and theoretical investigations of electromagnetic radiation induced by rock fracture," Israel Jour. of Earth Science, Vol. 49, 9-19, 2000.

© Copyright 2010 EMW Publishing. All Rights Reserved