Abstract
The use of electromagnetic fields applied to human tissues has proven to be beneficial in several applications, such as monitoring physiological parameters and delivering medical treatments. Often applications rely on targeted energy deposition into the tissue, or rely on wireless powering of implanted devices. In such cases, the system energy efficiency, the stability of the field, and ultimately the process safety could all benefit from minimizing the mismatch at the air-skin interface. In this article, the maximization of the electric field transmitted into the muscle tissue is initially addressed by optimizing a dielectric-only matching layer in terms of thickness and relative dielectric permittivity, and under realistic constraints on low-cost available materials. The propagation of the electromagnetic field inside a multilayered medium that represents the body is evaluated by using the wave-transmission chain matrix approach. Furthermore, an innovative solution, based on the application of a metasurface matching layer (MML), is proposed to significantly improve the performance of the matching, thus enhancing the electromagnetic fields reaching the targeted muscle tissue. A thorough assessment of the performance is carried out considering both the presence of an air gap, and the case of plane waves impinging at oblique incidence.
Highlights
Several studies have been devoted to the undesired interactions of electromagnetic fields and human [1]–[3] and to ways of preventing them [4]–[10]
We propose a solution based on the exploitation of a novel Metasurface Matching Layer (MML) and carry out a detailed study to demonstrate the remarkable improvement of the matching in terms of field penetrating into muscle tissue for a predefined maximum thickness
In order to prove the effectiveness of using a metasurface matching layer in achieving better electromagnetic field penetration in the muscle tissue, a test case frequency f0 = 1.5 GHz was considered as the working frequency [42], [43]
Summary
Several studies have been devoted to the undesired interactions of electromagnetic fields and human [1]–[3] and to ways of preventing them [4]–[10]. Most of the solutions proposed in literature to ease the penetration of an electromagnetic field into the human body rely on the application of a medium that is designed to reduce the reflection at the air-skin interface. It is apparent that the electromagnetic field penetration is greater at lower frequencies and that a thicker fat layer generally causes a lower transmission level with a sole exception around 3 GHz. By exploiting the boundary conditions at each interface, it is possible to evaluate the wave propagation in any point of the multilayered medium [41] and, in particular, between the impinging wave (c1) and the wave transmitted in the last medium (cn+1) by using the following relation: c1 b1
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
