This paper deals with a new definition of the Radar Cross Section (RCS) suitable for surface wave propagation in the HF band. Indeed, it can be shown that the classical definition of the RCS is dependent on distance for this kind of propagation. Also, in simulation, with the classical definition, the power estimated on the receivers using the radar equation is inaccurate. This is an issue for the performance assessment of High Frequency Surface Wave Radars. Thanks to the analysis of different wave propagation models, the differences between the space wave propagation and surface wave propagation have been highlighted. The required modifications of the RCS can then be performed. The proposed new definition is explained and justified in the paper and has been successfully applied to the computation of the RCS of naval targets. In addition, the implementation of this normalization term into the radar equation, and conversely the gain, is discussed. It can be observed that the received power, determined with the definitions adjusted to the surface wave propagation, is accurate. The different obtained results are illustrated and commented.
2. Bourey, N., F. Jangal, M. Darces, and M. Helier, "Enhancing field strength in HF propagation by using a transition between a metamaterial and the sea," 2013 7th European Conference on Antennas and Propagation (EuCAP), 2680-2684, April 2013.
3. Knott, E. F., J. F. Shaeffer, and M. T. Tuley, Radar Cross Section, IET Digital Library, January 2004.
4. Bannister, P. R., New formulas that extend Norton's farfield elementary dipole equations to the quasi-nearfield range, Technical Report NUSC-TR-6883, NAVAL UNDERWATER SYSTEMS CENTER NEW LONDON CT, January 1984.
5. Ratcliffe, J. A., "Scientists' reactions to Marconi's transatlantic radio experiment," Proceedings of the Institution of Electrical Engineers, Vol. 121, No. 9, 1033-1039, September 1974.
6. Zenneck, J., "Uber die Fortp anzung ebener elektromagnetischer Wellen langs einer ebenen Leiterflache und ihre Beziehung zur drahtlosen Telegraphie," Annalen der Physik, Vol. 328, No. 10, 846-866, 1907.
7. Sommerfeld, A., "Uber die Ausbreitung der Wellen in der drahtlosen Telegraphie," Annalen der Physik, Vol. 333, No. 4, 665-736, 1909.
8. Norton, K. A., "The propagation of radio waves over the surface of the Earth and in the upper atmosphere," Proceedings of the Institute of Radio Engineers, Vol. 25, No. 9, 1203-1236, September 1937.
9. Rotheram, S., "Ground-wave propagation. Part 2: Theory for medium and long distances and reference propagation curves," IEE Proceedings F --- Communications, Radar and Signal Processing, Vol. 128, No. 5, 285-295, October 1981.
10. Apaydin, G. and L. Sevgi, Radio Wave Propagation and Parabolic Equation Modeling, Wiley, October 2017, ISBN: 978-1-119-43211-1.
11. Houdzoumis, V. A., "Two modes of wave propagation manifested in vertical electric dipole radiation over a sphere," Radio Science, Vol. 35, No. 1, 19-29, January 2000.
12. Bremmer, H., "Applications of operational calculus to ground-wave propagation, particularly for long waves," IRE Transactions on Antennas and Propagation, Vol. 6, No. 3, 267-272, July 1958.
13. Bellec, M., S. Palud, P. Y. Jezequel, S. Avrillon, F. Colombel, and Ph. Pouliguen, "Measurements of surface waves radiated by a vertically polarized antenna over planar seawater at 5 MHz comparison to planar Earth models," 2014 IEEE Radar Conference, 0245-0250, May 2014, ISSN: 2375-5318.
14. Bellec, M., P. Y. Jezequel, S. Palud, F. Colombel, S. Avrillon, and P. Pouliguen, "Measurements process of vertically polarized electromagnetic surface-waves over a calm sea in the HF band over a spherical earth," 2015 9th European Conference on Antennas and Propagation (EuCAP), 1-5, April 2015, ISSN: 2164-3342.
15. Leontovich, M. A. and V. A. Fock, "Solution of propagation of electromagnetic waves along the Earth's surface by the method of parabolic equations," Journal of Physics, Vol. 10, 13-23, 1946.
16. Tappert, F. D., "The parabolic approximation method," Lecture Notes in Physics, 224-287, J. B. Keller and J. S. Papadakis, eds., Wave Propagation and Underwater Acoustics, Springer Berlin Heidelberg, Berlin, Heidelberg, 1977.
17. Barrick, D. E., "Theory of HF and VHF propagation across the Rough Sea, 1, the effective surface impedance for a slightly rough highly conducting medium at grazing incidence," Radio Science, Vol. 6, No. 5, 517-526, , eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/RS006i005p0051.
18. Podilchak, S. K., H. Leong, R. Solomon, and Y. M. M. Antar, "Radar cross-section modeling of marine vessels in practical oceanic environments for high-frequency surface-wave radar," 2009 IEEE Radar Conference, 1-6, May 2009, ISSN: 2375-5318.
19. Fabbro, V., P. Combes, and N. Guillet, "Apparent radar cross section of a large target illuminated by a surface wave above the sea," Progress In Electromagnetics Research, Vol. 50, 41-60, 2005.