Wireless, Batteryless, and Secure Implantable System-on-a-Chip for 1.37mmHg Strain Sensing with Bandwidth Reconfigurability for Cross-Tissue Adaptation
There is a growing interest in wireless and batteryless implants for long-term sensing of organ movements, core pressure, glucose levels, or other biometrics . Most research on such implants has focused on ultrasonic  and nearfield inductive [3-4] methods for power and communication, which require direct contact or close proximity (<1-5cm) to the human body. Recently, RF backscatter has emerged as a promising alternative due to its ability to communicate with far-field (> 10cm) wireless devices at ultra-low-power . While multiple proposals have demonstrated far-field RF backscatter in deep tissues, these proposals have been limited to tag identification and could neither perform biometric sensing nor secure the wireless communication links, which is critical for ensuring the confidentiality of the sensed biometrics and for responding to commands only from authorized users . Moreover, such far-field RF implants are susceptible to tissue variations which impact their resonance and hence their efficiency in RF backscatter and energy harvesting.