volume | PIER Journals

Abstract

Luebbers' and Maliuzhinets' solutions for diffraction by alossy wedge are compared in order to model the urban propagationchannel. Derivation, validity criteria and accuracy of impedanceboundary conditions (IBCs) --- as a main approximation embedded inthe Maliuzhinets' solution—are discussed. A modified (a slightlyimproved) Luebbers diffraction coefficient is proposed. The UniformTheory of Diffraction (UTD) Maliuzhinets diffraction coefficient isgiven in a structured form that might facilitate its use. Detailednumerical comparisons of the above-mentioned solutions with method-of-moments solutions using either exact boundary conditions or IBCsare done for canonical configurations.

1. Rossi, J. P. and A. J. Levy, "A ray model for decimetric radiowave propagation in an urban area," Radio Science, Vol. 27, No. 6, 971-979, 1992.
doi:10.1029/92RS01781

2. Lebherz, M., W. Wiesbeck, and W. Krank, "A versatile wave propagation model for the VHF/UHF range considering three dimensional," IEEE Trans. Ant. Prop., Vol. 40, No. 10, 1121-1131, 1992.
doi:10.1109/8.182444

3. K¨urner, T., D. J. Cichon, and W. Wiesbeck, "Evaluation and verification of the VHF/UHF propagation channel based on a 3-D-wave propagation model," IEEE Trans. Ant. Prop., Vol. 44, No. 3, 393-404, 1996.
doi:10.1109/8.486310

4. Luebbers, R. J., "Finite conductivity uniform GTD versus knife edge diffraction in prediction of propagation path loss," IEEE Trans. Ant. Prop., Vol. 32, No. 1, 70-76, 1984.
doi:10.1109/TAP.1984.1143189

5. Luebbers, R. J., "Comparison of lossy wedge diffraction coefficients with application to mixed path propagation loss prediction," IEEE Trans. Ant. Prop., Vol. 36, No. 1, 1031-1034, 1988.
doi:10.1109/8.7210

6. Luebbers, R. J., "A heuristic UTD slope diffraction coefficient for rough lossy wedges," IEEE Trans. Ant. Prop., Vol. 37, No. 2, 206-211, 1989.
doi:10.1109/8.18707

7. Kouyyoumjian, R. G. and P. H. Pathak, "A uniform geometrical theory of diffraction for an edge in a perfectly conducting surface," Proc. IEEE, Vol. 62, No. 11, 1448-1461, 1974.
doi:10.1109/PROC.1974.9651

8. Tiberio, R., G. Pelosi, and G. Manara, "A uniform GTD formulation for the diffraction by a wedge with impedance faces," IEEE Trans. Ant. Prop., Vol. 33, No. 8, 867-873, 1985.
doi:10.1109/TAP.1985.1143687

9. Tiberio, R., G. Pelosi, G. Manara, and P. H. Pathak, "High-frequency scattering from a wedge with impedance faces illuminated by a line source Part I: diffraction," IEEE Trans. Ant. Prop., Vol. 37, No. 2, 212-217, 1989.
doi:10.1109/8.18708

10. Bergljung, C. and L. G. Olsson, "A comparison of solutions to the problem of diffraction of a plane wave by a dielectric wedge," IEEEAnt. and Prop. Society International Symposium, Vol. 4, 1861-1864.

11. Demetrescu, C, C. C. Constantinou, and M. J. Mehler, "Scattering by a right-angled lossy dielectric wedge," IEE Proc.-Microw. Antennas Propag., Vol. 144, No. 5, October 1997.
doi:10.1049/ip-map:19971298

12. Leontovich, M. A., "Approximate boundary conditions for the electromagnetic field on the surface of a good conductor," Investigations on radiowave propagation, 1948.

13. Senior, T. B. A., "Approximate boundary conditions," IEEE Trans. Ant. Prop., Vol. 29, No. 5, 826-829, 1981.
doi:10.1109/TAP.1981.1142657

14. Senior, Approximate boundary conditions for, "Approximate boundary conditions for homogeneous dielectric bodies," J. of Electromagn. Waves and Appl., Vol. 9, No. 10, 1227-1239, 1995.

15. Huddleston, P. L., "Scattering by finite, open cylinders using approximate boundary conditions," IEEE Trans. Ant. Prop., Vol. 37, No. 2, 253-257, 1989.
doi:10.1109/8.18715

16. Wang, D.-S., "Limits and validity of the impedance boundary condition on penetrable surfaces," IEEE Trans. Ant. Prop., Vol. 35, No. 4, 453-457, 1987.
doi:10.1109/TAP.1987.1144125

17. James, G. L., "Geometrical Theory of Diffraction for Electromagnetic Waves," Peter Peregrinus Ldt., 1986.

18. Aidi, , M. and Approximation of the Maliuzhinets, "Approximation of the Maliuzhinets function," J. of Electromagnetic Waves and Applications, Vol. 10, 1395-1411, 1996.
doi:10.1163/156939396X00153

Dr. Mourad Aidi

Dr. J. Lavergnat