Wearable Metamaterial Textile for Enhanced Spatial Coverage of Deeply Implanted Device Communication System

Wireless communication is essential for deeply implanted devices, enabling remote and instantaneous health monitoring and alert applications. However, their performance is unstable when considered within a human body model, as signal transmission efficiency is limited to a specific direction rather than all directions. In this study, by introducing a metamaterial textile (MMT) structure that incorporates antennas integrated into wearable fabrics, quasi-omnidirectional radiation from a deeply implanted device was achieved. The structure consists of a focusing antenna, a spoof surface plasmon (SSP) structure, and four radiating elements. The focus antenna receives electromagnetic (EM) energy emitted by the deeply implanted device to excite the basic radiation mode of the patches via the SPP waveguide. Therefore, EM energy radiates in all directions, avoiding unnecessary harm to the human body. The entire system, including the deeply implanted antennas and metamaterial structure incorporating the antennas, operates in the 2.45-GHz industrial, scientific, and medical (ISM) band. Experimental results based on a human upper body model demonstrate that the stable signal spatial coverage is enhanced by up to 3.1 times compared to when the structure is not used.