A Regularized Boundary Element Formulation for Contactless SAR Evaluations within Homogeneous and Inhomogeneous Head Phantoms

TL;DR

This paper introduces a regularized boundary element method for contactless electromagnetic assessments that uses only electric measurements, enabling accurate dosimetry near sources in realistic head phantoms.

Contribution

It develops a novel regularized BEM scheme extending Calderon techniques, allowing high discretization and placement of measurement surfaces close to sources.

Findings

Well-conditioned problems independent of discretization density

Effective inhomogeneous head phantom simulations

Rapid dosimetric assessments with high accuracy

Abstract

This work presents a Boundary Element Method (BEM) formulation for contactless electromagnetic field assessments. The new scheme is based on a regularized BEM approach that requires the use of electric measurements only. The regularization is obtained by leveraging on an extension of Calderon techniques to rectangular systems leading to well-conditioned problems independent of the discretization density. This enables the use of highly discretized Huygens surfaces that can be consequently placed very near to the radiating source. In addition, the new regularized scheme is hybridized with both surfacic homogeneous and volumetric inhomogeneous forward BEM solvers accelerated with fast matrix-vector multiplication schemes. This allows for rapid and effective dosimetric assessments and permits the use of inhomogeneous and realistic head phantoms. Numerical results corroborate the theory and confirms the practical effectiveness of all newly proposed formulations.