Self-Powered RF Sensor Antenna for Implantable and Ingestible Medical Devices

Radio frequency (RF) devices such as antennas play a crucial role in implantable and ingestible medical devices (IMDs) by enabling wireless communication, energy harvesting, and localization links between transmitter (Tx) and receiver (Rx). Implantable and ingestible medical devices (IMDs) have transformed modern healthcare by enabling real-time monitoring and improving treatment outcomes. Radio frequency (RF) sensor antennas are key components in these devices and are widely used in biomedical applications for early diagnosis, treatment, and continuous health monitoring. RF-enabled IMDs monitor vital parameters such as temperature, blood pressure, glucose levels, oxygen saturation, pH, and blood composition. These antennas also support devices like pacemakers and defibrillators in managing cardiac conditions. In addition to human healthcare, they are applied in animal health monitoring and veterinary diagnostics. Implanted antennas detect physiological changes and wirelessly transmit data to external processing units, allowing real-time access for medical experts. This integration of RF sensing in IMDs enhances the ability to detect diseases early and deliver timely interventions, making them essential tools in both clinical and remote healthcare settings. This article presents two RF sensor antennas—FR-4 integrated (Ant-1) and miniaturized helical (Ant-2)—designed for implantable and ingestible medical devices, particularly in veterinary applications, operating in the 400–500 MHz range. Ant-1 is fabricated on an FR-4 substrate (51×28×1.6 mm³, ℇr = 4.4, tanδ = 0.002), resonating at 434 MHz with a bandwidth of 32.13 MHz and a total gain of approximately –36.92 dB without the phantom model and with the phantom in an acceptable range. Ant-2 is a miniaturized normal-mode helical antenna made of 0.9 mm diameter copper wire, also resonating at 434 MHz and both antennas integrate a surface acoustic wave (SAW) sensor to enhance wireless sensing. SAW sensors utilize acoustic waves on piezoelectric surfaces to detect parameters like temperature, pressure, strain, and displacement, enabling real-time, wireless physiological monitoring in biomedical applications.