This thesis presents a high efficiency RF to DC converter for RFID applications. The proposed circuit has been designed in 90 nm CMOS technology using a single RF source. It exploits an internal Vth cancellation technique along with a leakage current reducer. The circuit operates in two phases: Phase 1, applies a DC voltage between gate and drain to reduce the VDS of the PMOS transistor; and Phase 2 removes this DC voltage meanwhile by pulling the drain and source terminals of the same transistor to the same potential, reducing the sub-threshold leakage current and enhancing the power conversion efficiency. The simulation results show that high DC power up to 8.1µA can be delivered to the load. The PCE has been measured 36.3% at -14.3dBm and can be improved to 54.5% providing an impedance matching network between the source and rectifier input.

Tremendousadvancement inultra-low powerelectronics and radiocommunica tionshas significantly contributed towards the fabrication of miniaturized biomedical sensors capable of capturing physiological data and transmitting them wirelessly. However, most of the wearable sensors require a battery for their operation. The battery serves as one of the critical bottlenecks to the development of novel wearable applications, as the limitations offered by batteries are affecting the development of new form-factors and longevity of wearable devices. In this work, we introduce a novel concept, namely Intra-Body Power Transfer (IBPT), to alleviate the limitations and problems associated with batteries, and enable wireless, batteryless wearable devices. The innovation of IBPT is to utilize the human body as the medium to transfer power to passive wearable devices, as opposed to employingon-boardbatteries for each individual device. The proposed platform eliminates the on-board rigid battery for ultra-low power and ultra-miniaturized sensors such that their form-factor can be flexible, ergonomically designed to be placed on small body parts. The platform also eliminates the need for battery maintenance (e.g., recharging or replacement) for multiple wearable devices other than the central power source. The performance of the developed system is tested and evaluated in comparison to traditional Radio Frequency based solutions that can be harmful to human interaction. The system developed is capable of harvesting on average 217µW at 0.43V and provides an average sleep/high impedance mode voltage of 4.5V.