Low-power long-term implantable wireless telemetry for monitoring of physiological signals

In this study, we present a long term Implantable Medical Device (IMD) for continuous monitoring of physiological signals such as electrolytes, proteins, glucose, and temperature. The device consists of a small size dual band implantable antenna operating in Medical Implant Communications Service (MICS) (402 MHz-405 MHz) and Industrial, Scientific, and Medical (ISM) (2.4 GHz-2.48 GHz) bands with an interface circuit containing a transceiver, a microcontroller, and matching network components. In order to evaluate the transmission capability of the fabricated device, in vitro measurements are conducted using a tissue mimicking material and compared with in vivo measurements carried out in live porcine subjects. In vivo studies were performed over the course of two weeks to verify the proper functioning of the device. Results regarding the distance of the communication link between the device and base station and return loss of the implanted antenna are presented and discussed in detail.