290 research outputs found
Physical Meaning of Perturbative Solutions for Scattering From and Through Multilayered Structures With Rough Interfaces
No full textAbstract—Theoretical formulas without a clear comprehension
of their intrinsic meaning are of difficult use in the context of
practical applications. In this paper, we investigate on the physical
meaning of existing first-order solutions for the field scattered by
layered structures with rough interfaces, which were derived by
Imperatore et al. in the framework of perturbation theory. To
capture the intrinsic significance of the closed-form scattering solutions,
suitable expansions are rigorously performed by leveraging
on local scattering descriptors. The obtained series expansions,
which can be seen as ray series, can be then accurately analyzed
showing that each term has a direct physical explanation. The
analysis is carried out for both from- and through-layered-structure
scattering configurations. As a result, analytical perturbative
solutions turn out to be completely interpretable by simple
physical concepts, so that the global scattering response can be
interpreted as the superposition of single-scattering interaction
mechanisms taking place locally, which are filtered by the layered
structure. The meaning of the first-order approximation is also
discussed in the layered structure context. Finally, we give a complete
explanation for the scattering enhancement phenomenon
contemplated in the first-order limit
A Simple Path to the Small Perturbation Method for Scattering from Slightly Rough Dielectric Surfaces
No full textWe propose a perturbative method to compute electromagnetic scattering from slightly rough dielectric surfaces, which leads to the same result as the usual Small Perturbation Method (SPM) in a surprisingly simple way. The proposed method is based on three pillars: the volumetric perturbative approach, the reciprocity theorem, and a proper approximation of the electric field within the perturbation volume, that we name Internal Field Approximation (IFA). The proposed new mathematical derivation of the SPM turns out to be much simpler and more concise than the classical one. In addition, being based on a volumetric perturbation approach, it has the potential of dealing in future with surface and volume scattering within a unitary framework, which is useful in modelling scattering from, e.g., vegetated soil, snow-covered terrain, and inhomogeneous soils. Therefore, although the presented result is mainly theoretical, it can have important applications in remote sensing
Orazione funebre in lode dell' augustissimo imperatore Francesco Primo, Duca di Lorena e di Bar, Gran-Duca di Toscana &c. &c. &c. /
No full textMode of access: Internet.Library's copies 2 and 3 bound with: Solenni esequie celebrate nel Duomo di Firenze per la morte dell' augustissimo imperatore Francesco Primo ... Firenze : Nella Stamperia di S.A.R., 1765 (shelved as SPECIAL 87-B1689, c. 2 and 3)
Perturbative solution for the scattering from multilayered structure with rough boundaries
No full text
Perturbation Theory for Scattering from Multilayers with Randomly Rough Fractal Interfaces: Remote Sensing Applications
No full textA general, approximate perturbation method, able to provide closed-form expressions of scattering from a layered structure with an arbitrary number of rough interfaces, has been recently developed. Such a method provides a unique tool for the characterization of radar response patterns of natural rough multilayers. In order to show that, here, for the first time in a journal paper, we describe the application of the developed perturbation theory to fractal interfaces; we then employ the perturbative method solution to analyze the scattering from real-world layered structures of practical interest in remote sensing applications. We focus on the dependence of normalized radar cross section on geometrical and physical properties of the considered scenarios, and we choose two classes of natural stratifications: wet paleosoil covered by a low-loss dry sand layer and a sea-ice layer above water with dry snow cover. Results are in accordance with the experimental evidence available in the literature for the low-loss dry sand layer, and they may provide useful indications about the actual ability of remote sensing instruments to perform sub-surface sensing for different sensor and scene parameters
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