Showing papers by "David Schurig published in 2019"
TL;DR: In this article, the performance of subdermal ring designs for focusing electromagnetic fields inside the body for next-generation implantable medical devices was investigated for the Medical Implant Communications Service (MICS) band.
Abstract: In this letter, we investigate the performance of subdermal ring designs for focusing electromagnetic fields inside the body for next-generation implantable medical devices. We will concentrate on the Medical Implant Communications Service band $(\text{402} \text{--}\text{405 MHz})$ , but prepare our design at $\text{433 MHz}$ , the nearest Industrial, Scientific, Medical band. The designs include two-dimensional (2-D or coplanar) and 3-D arrays of circular rings and 3-D arrays of ellipses. The 3-D ring and ellipse arrays focus the fields more effectively than 2-D designs, through constructive coupling between the rings. Compared to the case where no rings are used, the power available from the focused field 20 mm below the skin is 2.24 times and 3.12 times larger if 3-D rings and 3-D ellipses are utilized, respectively. Rings can be used for circular polarization applications, and ellipses are more optimal for linear polarization applications.
4 citations
TL;DR: This article design, simulate, and evaluate the performance of planar 2D near-field magnifying lenses, based on the transformation-optic design principle, and investigates a grid-relaxed transformation, that results in material properties that are more amenable to implementation.
Abstract: It is well established that, under certain conditions, imaging systems with either isotropic negative index, or hyperbolic (indefinite) media can achieve super-resolution. However, achieving sub-diffraction limited imaging along with uniform aberration-free magnification can be challenging. In this article, we design, simulate, and evaluate the performance of planar 2D near-field magnifying lenses, based on the transformation-optic design principle. Specifically, we investigate a grid-relaxed transformation, that results in material properties that are more amenable to implementation. We discuss possible design choices in terms of: material properties, achievable resolution enhancement, adverse effect of loss tangent, magnification factor, and other design constraints affecting the imaging performance. We also present imaging performance results for a planar, near-field, 3× magnifier operating on a standard resolution target, based on a rigorous, 3D, electromagnetic simulation. This computational intensive result was achieved using cylindrical harmonic decomposition and the 2.5D electromagnetic simulation technique. Further, we investigate and propose a path to achieve higher magnification factors using cascaded elements.
3 citations
01 Jul 2019
TL;DR: An analytical method to phase any arrays of antennas or any metasurfaces made of elements with any arbitrary orientations or arbitrary polarizations is proposed and can pave the way for phasing arrays with more complicated configurations, and also, for real-time beam steering.
Abstract: We propose an analytical method to phase any arrays of antennas or any metasurfaces made of elements with any arbitrary orientations or arbitrary polarizations. We are unaware of such an analytical phasing technique in the literature. The method can pave the way for phasing arrays with more complicated configurations, and also, for real-time beam steering.