BIOMEDICAL ANTENNAS AND THEIR APPLICATIONS

Abstract

Implantable antenna research has gotten a lot of attention recently in the discipline of biomedical engineering. An implantable antenna working in Med-Radio, MICS, WMTS, and ISM bands for biotelemetry applications is presented in this report. The antenna of dimensions 20 x 30 x 1.6 mm3 has a rectangular C-shaped radiator patch, and an inverted rectangular C-shaped ground plane and CPW feeding is provided. The antenna is placed inside a 70 x 70 x 70 mm3 container filled with pork tissue for simulation of the real body environment. Here two pairs of substrate-superstrate are considered; the first pair is FR4 epoxy-Rogers RO3010 while the second pair is polyamide-alumina ceramic. At 865 MHz, a maximum SAR value of 1.5948 W/Kg is obtained, for a power input of 22.2 mW, for the former pair while for the latter peak SAR value of 1.5915 W/Kg is observed at a power input of 23 mW and these values are considered safe in accordance with the IEEE standard safety guidelines. The antenna exhibits wideband nature for both the pairs and peak gains of -6.3 dBi and -6.2 dBi are observed at 865 MHz for the respective substrate-superstrate pairs. This report also presents two conformal antennas for wireless capsule endoscopic systems for robust biotelemetry communications, one of them covers the 865 MHz band and the other one covers both 865 MHz and 2.4 GHz ISM bands. vi Biotelemetry is one of the applications of these bands. Two planar antennas are designed first and then they are conformed around a cylindrical capsule. It is observed that the antennas have wider bandwidth at respective bands. The peak realized gain for both antennas at 865 MHz is -18.1 dBi while the antenna with a bow and arrow shaped radiator has a peak gain of -13.3 dBi at 2.4 GHz. Since the capsule needs to be ingested by the patient for endoscopy, biocompatibility has been ensured. The maximum SAR values are obtained for both the antennas and are considered safe in accordance with the IEEE standard safety guidelines. The recommended antennas’ conformal design idea, omnidirectional radiations, and multiband capability with wider bandwidth in the ISM band(s) will improve the scope for capsule endoscopy and would provide valuable contribution in the domain of biotelemetry. The simulation is performed in ANSYS Electronics Desktop simulation software.