Page 74 - ITU Journal: Volume 2, No. 1 - Special issue - Propagation modelling for advanced future radio systems - Challenges for a congested radio spectrum

ITU Journal: ICT Discoveries, Vol. 2(1), December 2019

6. SUMMARY AND CONCLUSION 2) ITU-R, ”Propagation data required for the
design of Earth space maritime mobile
Analytical mathematical formulations for bi-static telecommunication systems,” Rec. ITU-R P.
scattering coefficients from a randomly rough 680-3, 1999.
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developed based on the following models: Small 3) ITU-R, ”Radio Noise,” Rec. ITU-R P.372-13,
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(PO), and Kirchhoff approximation (KA). Each 4) A. Khenchaf, “Bistatic scattering and
formulation has its own applicability domain as depolarization by randomly rough surfaces:
given in equations (11), (17) and (21). Those Application to the natural rough surfaces in X-
applicability domains are provided in Table 1 for band,” Waves in Random Media, II, PP. 61 – 89,
convenience. 2001.
Table 1 – Validity domains of bi-static scattering models [1]
5) D. Nie, M. Zhang, ”Bistatic scattering analysis
Bi-static scattering Validity range for two dimensional rough sea surfaces using
model an angular composite model,” International
Journal of Remote Sensing, Vol. 32, No. 24, PP.
SPM (Small perturbation < 0.3,
model) and ℓ> 4.71 9661–9672, 2011.
PO (Physical optics) ℓ>6 and 6) A. Ishimaru, Waves Propagation and
ℓ> 5.893 Scattering in Random Media, Academic Press,
KA (Kirchhoff > 3.16227 , ℓ > 6, New York, 1978.
approximation) cos +cos
and, ℓ > 4.17√ 7) A. Arnold-Bos, A. Khnechaf, and A.
Furthermore, mathematical analysis shows that Martin, ”Bistatic radar imagining of the
each of these models predicts null values for the marine environment-Part I: Theoretical
cross-polarized bi-static scattering coefficients background,” IEEE Transaction on
within the plane of incidence. In order to extend the Geoscience and Remote Sensing, Vol 45,
applicability domain of the above three models, No. 11, PP. 3372 – 3383, 2007.
they can be integrated through a two scale 8) F. T. Ulaby, R. K. Moore, and A. K. Fung,
scattering model [11]. The two scale scattering Microwave Remote Sensing Active and Passive,
model has the property of producing non-null Vol III, Artech House, Inc., 1986.
values for the cross-polarized coefficients within
the plane of incidence. 9) R. D. De Roo, F. T. Ulaby, ”Bistatic scattering
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Each of the three models can be used to predict the Geoscience and Remote Sensing, Vol. 24, No. 2,
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the complex relative permittivity of the Earth’s 10) A. Stogryn,”The apparent temperature of the
surface is required. In the case of land surface (soil), sea at microwave frequencies,” IEEE Trans.
the complex relative permittivity can be obtained Antenna and Propagation, Vol. AP-15, No. 2,
from equations (37) – (40) of [12] in terms of PP. 278 – 280, 1967.
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and composition. In the case of sea surface, the “Electromagnetic wave scattering from sea
complex relative permittivity may be obtained from and soil surfaces based on an improved two-
equations (14) – (27) of [12] in terms of frequency, scale model,” 2009 Intr. Radar Conference
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REFERENCES 12) ITU-R, ”Electrical characteristics of the
surface of the Earth,” Rec. ITU-R P. 527-5,
1) ITU-R, ”Feasibility of sharing between the FSS 2019.
(space to Earth) and Earth Exploration
Satellite (passive) and space research
(passive) services in the band 18.6–18.8 GHz,”
Rec. ITU-R RS. 1449-0, 2000.

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