Miniaturized multiband implantable antenna designs for in-body compact medical devices

This article presents a triple-band implantable antenna (TBIA) and its dual-band miniaturized configuration. The proposed TBIA has only a size of 102.87 mm(3) (9 mm x 9 mm x 1.27 mm). In addition, it provides a triple-band operation that covers all the Medical Implant Communication Service (MICS), Medical Device Radiocommunications Service (MedRadio), Medical Telemetry Service (WMTS), and Industrial, Scientific, and Medical (ISM) bands simultaneously. The compact structure with triple-band performance is essentially achieved by using a resonator consisting of three concentric split ring elements loaded with meandered lines and conductive paths between these elements. The proposed antenna was fabricated to verify the numerical design, and the characteristics of its return loss and radiation patterns were measured in minced pork meat. The miniaturized version of the TBIA has an ultracompact size of 3.18 mm(3) (3.5 x 3.5 x 0.26 mm(3)), and it offers a dual-band operation covering the WMTS and ISM bands. The proposed dual-band implantable antenna (DBIA) was achieved by using a thinner substrate and optimizing all design parameters of the TBIA. To the best of our knowledge, the proposed TBIA with the novel configuration is the first implantable antenna that simultaneously covers almost all frequency bands allocated for biotelemetry applications. Also, the proposed DBIA is the most miniature dual-band implantable antenna presented in the recent literature, considering the application frequencies.