Compact multi-band implantable antenna designs for versatile in-body applications

Abstract

In this paper, a quad-band implantable antenna (QBIA) and its triple-band miniaturized configuration are presented. The primary radiator of the proposed QBIA consists of four different types of concentric resonators excited by a microstrip feed line. The QBIA design has dimensions of 15 × 15 × 1.27 mm3, and it covers the Medical Device Radiocommunications Service (MedRadio), Medical Implant Communication Service (MICS), Medical Telemetry Service (WMTS), and Industrial, Scientific, and Medical (ISM) bands. The proposed antenna was fabricated to validate the numerical design, and the characteristics of its return loss and radiation patterns were measured in minced meat from pork. The miniaturized version of the QBIA has an ultra-compact size of 4.16 mm3 (4 × 4 × 0.26 mm3), and it offers a triple-band operation covering the ISM and WMTS bands. The proposed triple-band implantable antenna (TBIA) was achieved by using a thinner substrate and optimizing all design parameters of the QBIA. To the best of our knowledge, the suggested QBIA with the novel configuration is the first implantable antenna that simultaneously covers almost all frequency bands allocated for biotelemetry applications. Also, the proposed TBIA is the most miniature triple-band implantable antenna presented in the recent literature, considering the application frequencies.