A Stable Impedance-Matched Ultrawideband Antenna System Mitigating Detuning Effects for Multiple Biotelemetric Applications

Abstract

Implantable antennas are integral but challenging components of wireless biomedical implants. They are very sensitive to variations in host tissue environments and their performance is affected by coupling with circuitry and other components. To overcome these issues, a small-sized ultrawideband antenna system with stable impedance matching has been proposed. The suggested antenna has a small volume of 28.85 mm(3) and mitigates detuning due to changes in implantation scenarios or coupling with circuitry and batteries of the device. Initially, the antenna and devices were designed in a homogeneous muscle box using finite element method-based Ansys HFSS. For further verification and multiple applicability, the proposed antenna within the devices was implanted into different implantation sites in a realistic human Duke model and analyzed through finite-difference time-domain-based Sim4Life. Each full package device is composed of batteries, electronics, an antenna system, and sensor packs enclosed in a biocompatible casing. The proposed antenna was fabricated, devices were printed using 3-D printing technology, and measurements are carried out through immersion in a saline solution and in a porcine heart. A wide bandwidth of >= 84% in both simulations and measurements were achieved for all possible cases.