Progress In Electromagnetics Research
ISSN: 1070-4698, E-ISSN: 1559-8985
Home | Search | Notification | Authors | Submission | PIERS Home | EM Academy
Home > Vol. 34 > pp. 219-252


By L. W. Li, M. S. Yeo, and M. S. Leong

Full Article PDF (1,033 KB)

This paper presents an alternative analysis of obtaining radiated electromagnetic (EM) fields in a dielectric prolate spheroid using the perturbation technique. A circular loop antenna is used as a radiator on the top of the spheroid. The spheroid is approximated by the first a few terms of the Taylor series expansion (higher-order approximation), and coefficients for transmission and scattered EM fields are found using the perturbation method where the coefficients are also expanded into Taylor series and determined by matching the boundary conditions on the spheroidal dielectric surface. After the approximated coefficients and EM fields are obtained, validity of the approach is discussed and limitations are also addressed.

Citation: (See works that cites this article)
L. W. Li, M. S. Yeo, and M. S. Leong, "EM Fields Inside a Prolate Spheroid Due to a Thin Circular Loop: a Higher-Order Perturbation Approach," Progress In Electromagnetics Research, Vol. 34, 219-252, 2001.

1. Kerker, M., The Scattering of Light and Other Electromagnetic Radiation, Academic Press, New York, 1969.

2. Wang, D. S. and P. W. Barber, "Scattering by inhomogeneous nonspherical objects," Appl. Opts., Vol. 18, No. 8, 1190-1197, April 1979.

3. Wang, D. S., M. Kerker, and H. W. Chew, "Raman and fluorescent scattering by molecules embedded in dielectric spheroids," Appl. Opts., Vol. 19, No. 14, 2315-2328, July 1979.

4. Lakhtakia, A., V. K. Varadan, and V. V. Varadan, "Scattering and absorption characteristics of lossy dielectric, chiral, non-spherical objects," Appl. Opt., Vol. 24, 4146-4154, 1985.

5. Michalski, K. A., "The mixed-potential electric field integral equation for objects in layered media," Arch. Elek. Ubertragung., Vol. 39, 317-322, 1985.

6. Umashankar, K., A. Taflove, and S. M. Rao, "Electromagnetic scattering by arbitrary shaped three-dimensional homogeneous lossy dielectric objects," IEEE Trans. Antennas Propagat., Vol. 34, 758-766, 1986.

7. Lindell, I. V. and M. P. Silverman, "Plane-wave scattering from a nonchiral object in a chiral environment," J. Opt. Soc. Am. A, Vol. 14, No. 1, 79-90.

8. Li, L.-W., M.-S. Leong, and Y. Huang, "Electromagnetic radiation of antennas in the presence of an arbitrarily shaped dielectric object: Green dyadics and their applications," IEEE Transactions on Antennas and Propagation, Vol. 49, No. 1, 84-90, January 2001.

9. Sebak, A. A. and L. Shafai, "Performance of various integral equation formulations for numerical solutions of scattering by impedance objects," Can. J. Phys., Vol. 62, 605-615, 1984.

10. Sebak, A. and L. Shafai, "Scattering by a two-layer spherical dielectric object in a lossy medium illuminated by a loop carrying an arbitrary azimuthal mode," Canadian Journal of Physics, Vol. 67, No. 6, 617-623, June 1989.

11. Sinha, B. P. and A. R. Sebak, "Scattering by a conducting spheroidal object with dielectric coating at axial incidence," IEEE Trans. Antennas Propagat., Vol. 40, No. 3, 268-274, 1992.

12. Sherman, J. B., "Circular loop antennas with uniform current," Proc. IRE, Vol. 32, 534-537, Sept. 1944.

13. Lindsay, Jr., J. E., "A circular loop antenna with nonuniform current distribution," IRE Trans. Antennas Propagat., Vol. 8, No. 4, 439-441, July 1960.

14. Martin, Jr., E. J., "Radiation fields of circular loop antennas by a direct integration process," IRE Trans. Antennas Propagat., Vol. 8, No. 1, 105-107, Jan. 1960.

15. Wu, T. T., "Theory of the thin circular loop antenna," J. Math. Phys., Vol. 3, 1301-1304, 1962.

16. Rao, B. R., "Far field patterns of large circular loop antennas: Theoretical and experimental results," IEEE Trans. Antennas Propagat., Vol. 16, No. 2, 269-270, Mar. 1968.

17. Overfelt, P. L., "Near fields of the constant current thin circular loop antenna of arbitrary radius," IEEE Trans. Antennas Propagat., Vol. 44, No. 2, 166-171, 1996.

18. Werner, D. H., "An exact integration procedure for vector potentials of thin circular loop antennas," IEEE Trans. Antennas Propagat., Vol. 44, No. 2, 157-165, 1996.

19. Li, L.-W., M.-S. Leong, P.-S. Kooi, and T.-S. Yeo, "Exact solutions of electromagnetic fields in both near and far zones radiated by thin circular loop antennas: A general representation," IEEE Trans. Antennas Propagt., Vol. 45, No. 12, 1741-1748, December 1997.

20. Li, L.-W., C.-P. Lim, and M.-S. Leong, "Method of moments analysis of electrically large circular-loop antennas: Nonuniform currents," IEE Proceedings on Microwave, Antennas and Propagation, Vol. 146, No. 6, 416-420, November–December 1999.

21. Li, L.-W., M.-S. Yeo, and J. A. Kong, "Method of moments analysis of EM fields in a multilayered spheroid radiated by a thin circular loop antenna," IEEE Transactions on Antennas and Propagation, October 12, 2000.

22. Uzunoglu, N. K. and E. A. Angelikas, "Field distributions in a three-layer prolate spheroidal human body model for a loop antenna irradiation," IEEE Trans. Antenna and Propagat., Vol. 35, 1180-1185, 1987.

23. Balanis, C. A., Antenna Theory: Analysis and Design, 2nd edition, John Wiley & Sons, New York, 1997.

24. Li, L.-W., X.-K. Kang, and M.-S. Leong, Spheroidal Wave Functions in Electromagnetic Theory, John Wiley-Interscience, New York, 2001.

25. Li, L.-W., T.-S. Yeo, P.-S. Kooi, and M.-S. Leong, "Microwave specific attenuation by oblate spheroidal raindrops: An exact analysis of TCS’s in terms of spheroidal wave functions," Progress In Electromagnetics Research, J. A. Kong (Ed.), Vol. 18, 127–150, EMW Publishing, Cambridge, Boston, 1998. The abstract appears in J. Electromagn. Waves Applic., Vol. 12, No. 6, 709–711, June 1998.

26. Li, L.-W., T.-S. Yeo, and M.-S. Leong, "Bistatic scattering and backscattering of electromagnetic waves by conducting and coated dielectric spheroids: A new analysis using Mathematica package," Progress In Electromagnetics Research, Vol. 30, 251-271, EMW Publishing, Cambridge, Boston, 2001, Its Abstract appears in Journal of Electromagnetic Waves and Applications, Vol. 15, No. 1, 21–23, 2001.

27. Li, L.-W., M.-S. Leong, T.-S. Yeo, P.-S. Kooi, and K. Y. Tan, "Computations of spheroidal harmonics with complex argument: A review with an algorithm," Physical Review E, Vol. 58, No. 5, 6792-6806, November 1998.

28. Li, L.-W., M.-S. Leong, P.-S. Kooi, and T.-S. Yeo, "Spheroidal vector eigenfunction expansion of dyadic Green’s functions for a dielectric spheroid," IEEE Trans. Antennas Propagt., Vol. 49, No. 4, 645-659, April 2001.

29. Li, L.-W., X. K. Kang, M.-S. Leong, P.-S. Kooi, and T.-S. Yeo, "Electromagnetic dyadic Green’s functions for multilayered spheroidal structures: I - Formulation," IEEE Trans. Microwave Theory Tech., Vol. 49, No. 3, 532-541, March 2001.

30. Li, L.-W., P.-S. Kooi, M.-S. Leong, T.-S. Yeo, and M. Z. Gao, "Microwave attenuation by realistically distorted raindrops: Part I–Theory," IEEE Trans. Antennas Propagat., Vol. 43, No. 8, 811-822, August 1995.

31. Li, L.-W., M.-S. Leong, Y. L. Seow, T.-S. Yeo, and P.-S. Kooi, "Rainfall microwave attenuation of spherical raindrops: An efficient TCS formula using 3-D fitting," Microwave Opt. Tech. Lett., Vol. 17, No. 2, 121-125, February 1998.

32. Li, L.-W., T.-S. Yeo, P.-S. Kooi, and M.-S. Leong, "An efficient calculational approach to evaluation of microwave specific attenuation," IEEE Transactions on Antennas and Propagation, Vol. 48, No. 8, 1220-1229, August 2000.

32. Tai, C. T., Dyadic Green’s Functions in Electromagnetic Theory, 2nd edition, IEEE Press, Piscataway, New Jersey, 1994.

34. Collin, R. E., Field Theory of Guided Waves, 2nd edition, IEEE Press, Piscataway, New Jersey, 1991.

35. Stratton, J. A., Electromagnetic Theory, McGraw-Will, New York, 1941.

© Copyright 2014 EMW Publishing. All Rights Reserved