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In this communication, a semianalytical solution for the computation of the 2-D Green’s function for a cylindrical perfect electric conducting (PEC) enclosure containing an arbitrary number of confocal elliptic dielectric layers is provided. The approach relies on an expansion of the Green’s function into Mathieu functions, whose coefficients are found in an efficient way through a recursive procedure. The effectiveness of the technique is evaluated by comparisons with analytical formulas and against the results provided by independent numerical solvers. Moreover, the applicability of the solution to forward scattering problems using integral formulations is also assessed. In all the considered cases, the developed approach has been found to provide accurate results. [ABSTRACT FROM AUTHOR]

An innovative nonlinear inverse scattering approach in variable exponent Lebesgue spaces is proposed for microwave imaging purposes. The main objective of the approach is to overcome one of the main problems associated with reconstruction procedures developed in Lebesgue spaces with constant exponent, i.e., the need for the selection of the optimum Lebesgue-space norm parameter, which is critical for obtaining accurate reconstructions, and no exact rules exist for this choice. The approach proposed in this paper is oriented to tomographic imaging applications at microwave frequencies, for which the adopted inversion procedure is based on a Gauss–Newton method, which has been reformulated in the unconventional variable exponent Lebesgue spaces. The capabilities of the approach are demonstrated by a set of numerical simulations, in which cylindrical dielectric targets are inspected. Moreover, an experimental result is reported. [ABSTRACT FROM AUTHOR]

A solution for the computation of the 2-D Green's function for a multilayer elliptic cylinder in the presence of a perfectly conducting core is reported. It extends a previous solution limited to dielectric layers only. The Green's function is computed by an efficient recursive procedure based on eigenfunction expansions in terms of Mathieu functions. Numerical results and comparisons are provided in order to validate the approach and to assess the effectiveness of the proposed solution. [ABSTRACT FROM PUBLISHER]

An electromagnetic inverse scattering approach for imaging of shallow subsurface objects is reported. It extends to multifrequency processing, an efficient method previously developed for single frequency imaging. The considered approach is an iterative procedure based on an inexact-Newton method developed in L^p Banach spaces, which exhibits effective regularization capabilities and reduced over-smoothing effects. The approach is validated using numerical simulations in which cylindrical scatterers are reconstructed in a homogeneous lossy medium. Results are compared with those obtained using standard single frequency operating conditions. [ABSTRACT FROM PUBLISHER]

A recursive solution for the computation of the two-dimensional Green's function for the multilayer elliptic cylinder is reported. It is based on the scattering solution by this canonical scatterer through eigenfunction expansions in terms of Mathieu functions. The paper reports the mathematical details of the approach as well as several validation tests and comparisons. [ABSTRACT FROM PUBLISHER]

A hybrid approach is proposed to inspect three-dimensional homogeneous dielectric scatterers by using microwaves. Namely, the considered method consists in two steps: first, the supports of the scatterers are retrieved by the linear sampling method; then the permittivities of the targets are estimated by an ant colony optimization algorithm. The described strategy combines the efficiency of the linear sampling method with the global optimization capabilities of the stochastic procedure. Numerical results assess the capabilities of the approach also in the presence of noise. [ABSTRACT FROM AUTHOR]

In this paper, the use of a smart antenna system for the estimation of the directions of arrival (DOAs) of multiple waves is considered. An efficient method based on the support vector regression is proposed, in which the mapping among the outputs of the array and the DOAs of unknown plane waves is approximated by means of a family of support vector machines. Several numerical results are provided for the validation of the proposed approach, considering multiple impinging waves both in noiseless and noisy environments. [ABSTRACT FROM AUTHOR]

The optimization of difference patterns of monopulse antennas is considered. The synthesis problem is recast as an optimization problem by defining a suitable cost function. In particular, in this paper, the cost function is based on constraints on the side-lobe levels. A subarray configuration is adopted and the ex- citations of the difference pattern are approximately determined. The optimization problem is efficiently solved by a differential evolution algorithm, which is able to contemporarily handle real and integer unknowns. Numerical results are reported concerning classical array configurations previously considered in the literature. [ABSTRACT FROM AUTHOR]

Focuses on the detection of buried inhomogeneous elliptic cylinders by a memetic algorithm. Appraisal of the application of a global optimization procedure in the study; Computation of forward scattering; Expression of functionals of the problem; Assessment of the optimization method used in the study.