A Circularly Polarized Implantable Wideband Antenna for Bio-Telemetry Applications

Abstract

In this paper, a compact and circularly polarized circular-shaped wideband antenna is proposed for bio-telemetry applications. The radius of the proposed antenna is 8.4 mm and a 1 mm layer of Rogers-3010 is used as substrate. The resonance frequency of the proposed antenna is 910 MHz which is in ISM frequency band (902-928 MHz). The achieved -10 dB impedance and 3 dB AR bandwidth are 21.98% and 17.86% respectively in free space. Performance of the proposed antenna is also assessed in three-layer phantom model to validate it for biotelemetry applications. In phantom model simulation, the resonance frequency is shifted toward lower values by 200 MHz and the obtained -10 dB impedance bandwidth is 17.09%. Then, the shift in resonance frequency is mitigated by redesigning the antenna. The radius of the redesigned antenna is 8.1 mm. The attained maximum gain of the proposed antenna is -21.9 dBi and -15.18 dBi at the resonance frequency in the free space and in phantom model respectively. In addition, the specific absorption rate (SAR) inside phantom model is determined for determining biocompatibility and patient safety. The good radiation performance with circular polarization makes the antenna suitable for using in practical implantable biomedical applications.