In Vivo Testing of a Miniature 2.4/4.8 GHz Implantable Antenna in Postmortem Human Subject

We present a novel miniaturized dual-band implantable antenna for microwave backscattering at 2.4/4.8 GHz. These bands are recently emerging as highly promising for batteryless implants, viz., implants that receive power from an exterior interrogator at 2.4 GHz and backscatter their sensed signals at 4.8 GHz. Compared to the smallest reported 2.4/4.8 GHz implantable antenna, the proposed design is miniaturized by 39%, and exhibits higher gain by 10.3 dB (at 2.4 GHz) and 2.6 dB (at 4.8 GHz). To validate the antenna performance under anatomically correct conditions, postmortem human subject (PMHS) testing is performed. To the best of our knowledge, this is the first time that implantable antennas are tested in PMHS and further compared versus simulations in tissue-emulating models. Notably, good agreement exists between the two, with the proposed antenna exhibiting a reflection coefficient of <-4.5 dB at both 2.4 and 4.8 GHz for all six subcutaneous locations measured: left/right sides of thigh, hip, and abdomen.