In this paper, method of moment and modified physical optical hybrid method is used to analyze the scattering from 3-D PEC object buried under rough surface. The random rough ground surface is characterized with Gaussian statistics for surface height and for surface correlation function. The air-earth interface and the object are all replaced by the corresponding equivalent currents and the equivalent current on the ground surface is divided into two parts: the current caused by the incident wave which is named as incident current, and the current caused by buried object which is named as scattered current. The incident currents are obtained by PO approximation and the scattered currents are related to the current on the buried scatter by a modified PO method in this work. Only the current of scatter is considered as unknown and will be solved by MoM. After obtaining the current of scatter, the scattered current on the ground surface is calculated by the modified PO approximation. And the scatter field will be calculated by using the scattered current. In order to validate the hybrid method proposed in this paper, several numerical examples are given and compared with the results of MoM.
2. Chen, X., D. Liang, and K. Huang, "Microwave imaging 3- D buried objects using parallel genetic algorithm combined with FDTD technique," Journal of Electromagnetic Waves and Applications, Vol. 20, No. 13, 1761-1774, 2006.
3. Chen, X., K. Huang, and X.-B. Xu, "Microwave imaging of buried inhomogeneous objects using parallel genetic algorithm combined with FDTD method," Progress In Electromagnetics Research, Vol. 53, 283-298, 2005.
4. Thomas, V., J. Yohannan, A. Lonappan, G. Bindu, and K. T. Mathew, "Localization of the investigation domain in electromagnetic imaging of buried 2-D dielectric pipelines with circular cross section," Progress In Electromagnetics Research, Vol. 61, 111-131, 2006.
5. Cui, T. J., W. Wiesbeck, and A. Herschlein, "Electromagnetic scattering by multiple dielectric and conducting objects buried under multi-layered media — Part I: Theory; Part II: Numerical implementation and results," IEEE Trans. Geosci. Remote Sensing, Vol. 36, No. 3, 526-546, 1998.
6. Cui, T. J. and W. C. Chew, "Fast evaluation of Sommerfeld integrals for EM scattering and radiation by three-dimensional buried objects," IEEE Trans. Geosci. Remote Sensing, Vol. 37, No. 3, 877-900, 1999.
7. Zhang, Y. H., B. X. Xiao, and G. Q. Zhu, "An improved weak-form BCGS-FFT combined with DCIM for analyzing electromagnetic scattering by 3-D objects in planarly layered media," IEEE Trans. Geosci. Remote Sensing, Vol. 44, No. 12, 3540-3546, 2006.
8. Zhang, G., L. Tsang, and K. Pak, "Angular correlation function and scattering coefficient of electromagnetic waves scattered by a buried object under a two-dimensional rough surface," J. Opt. Soc. Am. A., Vol. 15, No. 12, 2995-3002, 1998.
9. El-Shenawee, M., C. Rappaport, E. L. Mille, and M. B. Silevitch, "Three-dimensional subsurface analysis of electromagnetic scattering from penetrable/PEC objects buried under rough surfaces: Use of the steepest descent fast multipole method," IEEE Trans. Geosci. Remote Sensing, Vol. 39, No. 6, 1174-1182, 2001.
10. El-Shenawee, M., "The multiple interaction model for nonshallow scatterers buried beneath 2-D random rough surfaces," IEEE Trans. Geosci. Remote Sensing, Vol. 40, No. 4, 982-987, 2002.
11. Jakobus, U. and F. M. Landstorfer, "Improved PO-MM hybrid formulation for scattering from three-dimensional perfectly conducting bodies of arbitrary shape," IEEE Trans. Antennas Propagat., Vol. 43, No. 2, 162-169, 1995.
12. Jakobus, U. and F. M. Landstorfer, "Improvement of the POMoM hybrid method by accounting for effects of perfectly conducting wedges," IEEE Trans. Antennas Propagat., Vol. 43, No. 10, 1123-1129, 1995.
13. Taboada, J. M., F. Obelleiro, and J. L. Rodriguez, "Improvement of the hybrid moment method-physical optics method through a novel evaluation of the physical optics operator," Microwave Opt. Technol. Lett., Vol. 30, No. 5, 357-363, 2001.
14. Wei, X. C. and E. P. Li, "Wide-band EMC analysis of on-platform antennas using impedance-matrix interpolation with the moment method-physical optics method," IEEE Trans. Electromagnetic Compatibility, Vol. 45, No. 3, 552-556.
15. Zhai, H. and C. Liang, "A simple iterative method for considering multibounce in PO region of MoM-PO," Microwave Opt. Technol. Lett., Vol. 40, No. 2, 110-112, 2004.
16. Djordjevic, M. and B. M. Notaros, "Higher order hybrid method of moments-physical optics modeling technique for radiation and scattering from large perfectly conducting surfaces," IEEE Trans. Antennas Propagat., Vol. 53, No. 2, 800-813, 2005.
17. Chen, H. T., J. X. Luo, and G. Q. Zhu, "Using UV technique to accelerate the MM-PO method for three-dimensional radiation and scattering problem," Microwave Opt. Technol. Lett., Vol. 48, No. 8, 1615-1618, 2006.
18. Chen, M., X. W. Zhao, Y. Zhang, and C.-H. Liang, "Analysis of antenna around NURBS surface with iterative MoM-PO technique," Journal of Electromagnetic Waves and Applications, Vol. 20, No. 12, 1667-1680, 2006.
19. Rao, S. M., D. R. Wilton, and A. W. Glisson, "Electromagnetic scattering by surface of arbitrary shape," IEEE Trans. Antennas Propagat., Vol. 30, No. 2, 409-418, 1982.
20. King, R. W. P. and M. F. Brown, Lateral electromagnetic waves along plane boundaries: A summarizing approach, Proceedings of the IEEE, Vol. 72, No. 5, 595-611, 1984.