Salvatore Caorsi

In this paper the potential impact of distributed computing on the performances of microwave CAD tools is analysed. A possible implementation of an evolutionary based parallel CAD tool is provided and a numerical assessment of its performances is carried out.

This paper presents a microwave approach for nondestructive evaluation (NDE). It is based on the application of a genetic algorithm (combined with a deterministic procedure) to a global optimization approach for dielectric reconstruction purposes. In the following, the formulation of the approach is outlined and some examples of the obtained numerical results are provided.

By using an inductive procedure we prove that the Galerkin finite element approximations of electromagnetic eigenproblems modelling cavity resonators by elements of any fixed order of either Nedelec's edge element family on tetrahedral meshes are convergent and free of spurious solutions. This result is not new but is proved under weaker hypotheses, which are fulfilled in most of engineering applications. The method of the proof is new, instead, and shows how families of spurious-free elements can be systematically constructed. The tools here developed are used to define a new family of spurious-free edge elements which, in some sense, are complementary to those defined in 1986 by Nedelec.

The purpose of this paper is to present a microwave imaging approach for the determination of the position, the orientation and dimensions of a crack located inside a lossy dielectric host medium. The inversion procedure is based on a genetic algorithm which allows to iteratively generate a sequence of trial solutions minimizing a suitable cost function. The dependence of the performances of the proposed microwave imaging approach on the conductivity value of the host medium is checked. Moreover, the robustness of the algorithm to operate with noisy data is evaluated. Finally, the reconstruction of an irregular crack is considered.

This paper deals with the scattering by nonlinear objects illuminated by time-periodic incident electromagnetic fields. An integral formulation of the three-dimensional full-vector scattering by bounded dielectric objects is described and a formal series solution is obtained. A numerical solution is then achieved by discretizing the continuous model and by using a statistical-cooling procedure (i.e., simulated annealing) to solve the resulting energy function. Numerical results on simple nonlinear objects are reported

A formal series solution is presented for the electromagnetic field distribution inside a rectangular waveguide in which a nonlinear dielectric slab has been inserted. The solution is developed in terms of the Green function of rectangular waveguides with perfectly conductive walls. We assume the waveguide to be excited in the TE10 mode at a frequency f0. The approach takes into account the higher-order mode generation at f0 and at different frequencies. We also assume the nonlinear slab to be isotropic and inhomogeneous (even without any impressed field). The paper shows how the problem solution (i.e. the computation of the series coefficients) can be reduced to the solution of a system of coupled integral equations. The formal solution is derived for two cases : an infinite waveguide and a short-circuited waveguide