A Miniaturized Triple-Band Implantable Antenna System for Bio-Telemetry Applications

Abstract

This communication presents a miniaturized triple band implantable antenna system for multiple biotelemetry applications, which operates at the industrial, scientific, and medical (ISM) band (902-928 MHz and 2400-2483.5 MHz) and the midfield band (1824-1980 MHz). These bands are intended for the function of data telemetry, wireless power transfer, and power saving. The recommended antenna system is comprised of two implantable devices, a capsule type for deep tissue implantation and a flat type for skin implantation. The volume of these devices is 647 mm(3) and 425.6 mm(3), respectively. The compact size of the proposed antenna system is 21 mm(3) (7 mm x 6 mmx 0.5 mm), which is the smallest size yet presented. The miniaturization is achieved by meandering the shape of the radiating patch, adding an open-end ground slot, and introducing a shorting pin between ground plane and radiating patch. In the proposed antenna, simulated bandwidth is 8.7% and 7.3% at the ISM bands and 8.2% at the midfield band, and the measured bandwidth in a saline solution is 14.7% and 24.8% at the ISM bands and 13.1% at the midfield band. Finally, a link budget is calculated at different data rates to specify a range for data telemetry.