1998 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.

IEEE Transactions on Antennas and Propagation
Volume 46 Number 6, June 1998

Application of the Fast Far-Field Approximation to the Computation of UHF Pathloss over Irregular Terrain

Page 881.

Abstract:

The recent availability of fast numerical methods has rendered the integral-equation approach suitable for practical application to radio planning and site optimization for UHF mobile radio systems. In this paper, we describe a conceptually simple scheme for the efficient computation of UHF radial propagation loss over irregular terrain, which is based on the fast far-field approximation. The method is substantially faster than conventional integral-equation (IE) solution techniques. The technique is improved by incorporating the Green's function perturbation method and we outline a way in which the formulation can be made more exact. Computational issues such as terrain profile truncation and the effect of small-scale roughness are addressed. The method has been applied to gently undulating terrain and compared to published experimental results in the 900-MHz band. It has also been successfully applied to more hilly terrain and to surfaces with buildings added.

References

1. J. T. Hviid, J. Bach Anderson, J. Toftgärd, and J. Bøjer, "Terrain based propagation model for rural area--An integral equation approach," IEEE Trans. Antennas Propagat., vol. 43, pp. 41-46, Jan. 1995.
2. J. T. Johnson, R. T. Shin, J. C. Eidson, L. Tsang, and J. A. Kong, "A method of moments model for VHF propagation," IEEE Trans. Antennas Propagat., vol. 45, pp. 115-125, Jan. 1997.
3. C. C. Lu and W. C. Chew, "Fast far-field approximation for calculating the RCS of large objects," Microwave Opt. Tech. Lett., vol. 8, no. 5, pp. 238-241, 1995.
4. D. Moroney and P. J. Cullen,"The Green's function perturbation method for the solution of electromagnetic problems," Progress Electromagn. Res. PIER, vol. 15, pp. 221-252, 1997.
5. C. A. Balanis, Advanced Engineering Electromagnetics.New York: Wiley, 1989.
6. D. Holliday, L. L. DeRaad, Jr., and G. J. St.-Cyr, "Forward backward: A new method for computing low grazing angle scattering," IEEE Trans. Antennas Propagat., vol. 44, pp. 722-729, 1996.
7. D. A. Kapp and G. Brown,"A new numerical method for rough surface scattering calculations," IEEE Trans. Antennas Propagat., vol. 44, pp. 711-721, 1996.
8. E. Bleszynski, M. Bleszynski, and T. Jaroszewicz, "AIM: Adaptive integral method for solving large-scale electromagnetic scattering and radiation problems," Radio Sci., vol. 31, pp. 1225-1251, 1996.
9. E. Michielssen and A. Boag, "A multilevel matrix decomposition algorithm for analysing scattering from large structures," IEEE Trans. Antennas Propagat., vol. 44, pp. 1086-1093, Aug. 1996.
10. V. Rokhlin, "Rapid solution of integral equations of scattering theory in two dimensions," J. Comput. Phys., vol. 86, pp. 414-439, 1990.
11. R. L. Wagner and W. C. Chew, "A ray-propagation fast multipole algorithm," Microwave Opt. Tech. Lett., vol. 7, no. 10, pp. 435-438, 1994.
12. P. Cullen and C. Brennan, "Efficient techniques for the computation of UHF grazing incidence scattering," in Int. Conf. Electromagn. Adv. Applicat., Torino, Italy, Sept. 1997, pp. 351-355.
13. R. M. James, "A contribution to scattering calculation for small wavelengths--The high frequency panel method," IEEE Trans. Antennas Propagat., vol. 38, pp. 1625-1630, Oct. 1990.
14. K. Aberegg and A. Peterson, "Integral equation asymptotic phase method to two-dimensional scattering," IEEE Trans. Antennas Propagat., vol. 43, pp. 534-537, May 1995
15. D. Moroney and P. J. Cullen,"A fast integral equation approach to UHF coverage estimation," in Mobile Personal Commun.: Proc. 2nd Joint Cost 227/231 Workshop Mobile Personal Commun., Florence, Italy, Apr. 1995, pp. 20-21.
16. D. Moroney, "Computational methods for the calculation of electromagnetic scattering from large-scale perfect electrical conductors," Ph.D. dissertation, Univ. Dublin, Trinity College, Dublin, Ireland, 1995.
17. P. McSharry, D. Moroney, and P. J. Cullen, "Wave scattering by a two-dimensional pressure release surface based on a perturbation of the Green's function," Jnt. J. Acoust. Soc. Amer., vol. 98, no. 3, pp. 1699-1716, Sept. 1995.
18. P. McSharry, P. J. Cullen, and D. Moroney, "Wave scattering by a two-dimensional bandlimited fractal surface based on a perturbation of the Green's function," Jnt. J. Appl. Phys., vol. 78, pp. 6940-6948, Dec. 1995.
19. C. Brennan, P. J. Cullen, and L. Rossi, "A high speed adaptive methodology for calculating UHF propagation loss over terrain," in 8th IEEE Int. Symp. Personal, Indoor, Mobile Radio Commun., Helsinki, Finland, Sept. 1997, pp. 629-634.