Compact helical antenna for smart implant applications

Smart implants are envisioned to revolutionize personal health care by assessing physiological processes, for example, upon wound healing, and communicating these data to a patient or medical doctor. The compactness of the implants is crucial to minimize discomfort during and after implantation. The key challenge in realizing small-sized smart implants is high-volume cost- and time-efficient fabrication of a compact but efficient antenna, which is impedance matched to 50 Omega, as imposed by the requirements of modern electronics. Here, we propose a novel route to realize arrays of 5.5-mm-long normal mode helical antennas operating in the industry-scientific-medical radio bands at 5.8 and 2.4 GHz, relying on a self-assembly process that enables large-scale high-yield fabrication of devices. We demonstrate the transmission and receiving signals between helical antennas and the communication between an antenna and a smartphone. Furthermore, we successfully access the response of an antenna embedded in a tooth, mimicking a dental implant. With a diameter of similar to 0.2 mm, these antennas are readily implantable using standard medical syringes, highlighting their suitability for in-body implant applications.