Differentially Fed Compact Triple-band Antenna for Implantable Medical Devices

A compact triple-band antenna for biomedical telemetry applications is presented in this paper. The proposed antenna operates at MedRadio band (402-406 MHz) and ISM bands (902-928 MHz & 2.40-2.48 GHz) whose resonance frequencies are 402 MHz, 914 MHz, and 2.43 GHz. A meandering slotted patch over the silicon substrate of standard 0.275 mm thickness and a sorting pin is used to achieve the desired results and size. The performances of the proposed antenna are evaluated and studied in free space, in a skin phantom cube and inside the fat of a six-layer phantom model using Ansoft HFSS software. Differential feeding is utilized in the design and the volume of the presented antenna is only 46.475 cubic millimeter excluding superstrate. The simulated bandwidth of the proposed antenna is 11.7%, 0.77%, and 2.88% at the resonant frequencies respectively. Finally, the specific absorption rate is determined at the center frequencies in the phantom model for the assessment of patient safety. Compact structure, bio-compatibility, improved realized gain and operation over three different biomedical frequency bands enables the antenna to be used with implantable medical devices with great possibilities.