Loading [MathJax]/extensions/MathMenu.js
Martina T. Bevacqua - IEEE Xplore Author Profile

Showing 1-25 of 100 results

Filter Results

Show

Results

The ability to enforce a given behaviour on the electromagnetic field intensity distribution is relevant in a wide range of applications, including the particularly challenging case where shaping is required in heterogeneous media. In this respect, with reference to scalar fields, the paper proposes a new effective approach to design the optimal complex excitations feeding an antenna array able to...Show More
RFID-based localization refers to determining the position of an object equipped with an RFID tag by analyzing the signals backscattered by the tag and collected by the readers. In this paper, we present an exploration of multi-frequency and multi-view localization using UHF -RFID passive tags. We propose two approaches based on, respectively, Particle Filter (PF) and Beamforming (BF) imaging meth...Show More
This contribution focuses on the analytical derivation of the Green’s function of the ideal lossless Veselago lens. The problem is dealt with by considering the lens as a scattering object. Then, the electromagnetic field of a linesource illuminating the lens is seen as the sum of the field due to the line-source in free space plus the scattered field due to the lens. The asymptotic evaluation is ...Show More
In this contribution, the virtual experiments framework is proposed for the solution of 3D scalar inverse scattering problems. In particular, a new linearization of the relevant data equation is given based on a suitable design of the virtual experiments, and a preliminary test is performed against a simple scenario.Show More
A new linearized approach for the 3D inverse scattering problem based on a convenient decomposition of the relevant Green's function is proposed. In particular, the 3D scalar problem is addressed as it is propaedeutic for the fully vectorial one and is significant in several applications. A preliminary result with simulated data is reported to show the performance of the proposed linear procedure ...Show More
We focus on some recent advances in solution methods for the inverse scattering problem. In particular, attention is concentrated on the virtual experiments framework and the possibility of rewriting in a convenient fashion the basic scattering equations. Moreover, a new unconventional application of inverse scattering is discussed, which is the ’inverse design’ framework. Finally, some considerat...Show More
In this contribution the Virtual Experiments paradigm as applied to the solution of the canonical inverse scattering problem in the 2D scalar case is addressed to show present performance and limitations, and possibly give some insights to overcome these latter. It will be shown, through analytic findings and numerical results (shown at the conference), the usefulness of such a study in the framew...Show More
Magnetic Resonance imaging based Electrical Properties Tomography (MR-EPT) is a non-invasive technique that measures the electrical properties (EPs) of biological tissues. In this work, we present and numerically investigate the performance of an unrolled, physics-assisted method for 2D MR-EPT reconstructions, where a cascade of Convolutional Neural Networks is used to compute the contrast update....Show More
The 2-D problem of finding the electric field for a line-source illuminating a lossless Veselago lens (VL) is cast as an integro-differential equation (IDE). The integral corresponds to a surface integral of the total tangential magnetic field on the boundaries of the lens. The IDE is obtained using an incident/scattered-field decomposition such that the VL is considered to be the scatterer. The n...Show More
The contribution addresses the tridimensional inverse scattering scalar problem, by introducing a new smart rewriting of the scattering equations such to reduce the degree of nonlinearity of the inverse problem. The analysis of the norm of the relevant internal radiation operator is performed in comparison with the standard one. This analysis can open the way for exploring new possibilities and op...Show More
In this article, we investigate the virtual experiments (VE) setting by means of analytical solution of the far-field equation, that is the equation underlying the linear sampling method. In particular, an analytical expression for the internal field is derived in case of penetrable circular cylinders, which provides a straightforward and more comprehensive overview of the VE settings with particu...Show More
A new method for support reconstruction is proposed based on the contraction integral equation, a smart rewriting of the scattering equations introduced to alleviate the nonlinearity of the inverse scattering problem. Within such a model, in the case of strong and/or metallic targets, or by a suitable choice of a hyperparameter, the inherent auxiliary function encoding the target properties is exp...Show More
The accurate quantitative estimation of the electromagnetic properties of tissues can serve important diagnostic and therapeutic medical purposes. Quantitative microwave tomography is an imaging modality that can provide maps of the in-vivo electromagnetic properties of the imaged tissues, i.e. both the permittivity and the electric conductivity. A multi-step microwave tomography approach is propo...Show More
In this contribution, the field intensity shaping is addressed. This problem is relevant in several applications, including hyperthermia treatment planning, magnetic resonance radiofrequency shimming, satellite and radio communications, as well as in antenna array synthesis theory. The aim is the design of the array complex excitations such to ensure uniform and maximum field intensity distributio...Show More
Microwave imaging (MWI) is a useful tool to identify the characteristics of unknown objects in a non-invasive fashion. It offers advantages such as low cost and portability compared to other medical imaging methods. However, MWI faces challenges in solving the underlying inverse scattering problem (ISP) due to non-linearity and ill-posedness. Traditional optimization methods have limitations relat...Show More
The new integral equation model has been recently introduced in literature to alleviate the non-linearity and complexity of the inverse scattering problem. It consists of a smart rewriting of the scattering equations and is usually used for quantitative inversion of unknown targets. On the other hand, in this contribution, the idea underlying a new method for inverse obstacle problem, which aims t...Show More
In this contribution, some of the main results of millimeter-wave imaging for breast cancer diagnosis using both radar and tomographic approaches are presented. In addition, the idea of using a dual-step approach for reconstructing the dielectric profile of the anomaly using the morphological information provided by the faster and computationally less expensive radar approach is presented.Show More
In this contribution, preliminary analyses are performed on the use of focused beams for imaging of PEC targets. In particular, the data collected in case of Bessel-shaped beam as incident field are processed by means of the well-known physical optics approximation and also by a recently introduced qualitative method, which exploits sparsity regularization and solves the related inverse source pro...Show More
In this contribution, the aim is to design the complex excitations feeding a biomedical array applicator such to ensure uniform and maximum field intensity distribution inside a given region of interest, while keeping it under control in some other regions. This issue is relevant in several applications, including hyperthermia treatment planning and magnetic resonance radiofrequency shimming. To t...Show More
Herein, we propose the use of artificial (or numerical) backgrounds for electromagnetic inversion inside conducting enclosures. Such enclosed imaging systems are used both due to external constraints (e.g., grain bin imaging), or in order to provide external shielding and easy-to-model boundary conditions (e.g., in stroke or breast imaging systems). We use the orthogonality sampling method (OSM), ...Show More
Over the past two years, the spread of COVID-19 has spurred the use of information and communication technologies (ICT) in aid of healthcare. The need to guarantee continuity to care has promoted research and industry activities aimed at developing solutions for the digitalization of the procedures to be performed to provide health services, even in emergency scenarios. Digital collection, transmi...Show More
Quantitative microwave imaging employing an ideal Veselago lens is demonstrated using synthetic 2D experiments. Reconstructions of the complex-valued dielectric constant of an arbitrary object-of-interest are obtained from noiseless data using a non-iterative technique. A closed-form Veselago lens Green’s function is utilized in the formulation of the problem. The contrast sources corresponding to...Show More
Breast cancer is one of the most diagnosed forms of cancer among women worldwide. However, the survival rate is very high when the tumor is diagnosed early. The search for diagnostic techniques increasingly able to detect lesions of the order of a few millimeters and to overcome the limitations of current diagnostic techniques (e.g., the X-ray mammography, currently used as standard for screening ...Show More
The canonical problem of designing the complex excitations feeding an array such to ensure a desired field intensity distribution inside a given region of interest, while keeping it under control in some other regions, is addressed. To this end, an auxiliary physics inspired model for the induced total field is proposed, whose off-line analysis allows a simplified approach to understand the conven...Show More