A Comparison of Solid, Mesh, and Segmented Strip Dipoles in a Subdermal Environment

Abstract

The objective of this paper is to evaluate the feasibility of subdermal (tattoo) antennas in the fat layer, which use the low conductivity of the fat to electrically insulate a dipole antenna. The current research in polymer engineering is moving toward materials that can be injected as fluids that turn to soft, conductive solids at body temperature; this paper anticipates using these materials for tattooed subdermal antennas. Simulations and measurements were used to evaluate the current distributions that are shared between antennas with and without voids (solid, segmented, and meshed strip dipole antennas) and surrounding body tissues to give insight into the performance of subdermal antennas and their coupling to the body. The body tissues play a strong role in adapting the current distributions. The high dielectric materials electrically shorten the antenna. The high conductivity muscle conducts or guides current into the body. Any voids in the antennas (e.g., gaps between segments or holes in the mesh) are particularly important, as they generate stronger coupling to the tissues. The feasibility of using fat as insulation is verified in simulation and confirmed with measurement.