Bootstrapped Rectifier–Antenna Co-Integration for Increased Sensitivity in Wirelessly- Powered Sensors

摘要

This paper addresses the challenge of increasing the sensitivity of wireless powering approaches to achieve targeted output voltage for wirelessly-powered sensors with the compact area. The design exploits a bootstrapping approach where the rectifier first stage and the antenna are reused to increase the rectifier output voltage following an initial charging phase. Area-constrained rectifier-antenna co-optimization results in a compact highQ 2.4-GHz antenna with 1.2-cm^{2area which is then used in two topologies [cross-coupled (CC) and cross-coupled pMOS (CP)] based on the proposed bootstrapping concept. Both topologies increase the rectifier output voltage with no additional off-chip inductors or capacitors. The CC/CP topologies and the associated logic are integrated into a 65-nm CMOS with the IC occupying 1.1 mm2of the area. The CC topology achieves input sensitivity of -34.5 dBm for 1.6-V output voltage with RLOAD of 1.8 MQ, while the CP topology achieves -26.5-dBm input sensitivity with the 2.5-V output voltage and RLOAD of 250 kg. These results confirm more than 2 × longer distance for wirelessly powering sensors compared to state of the art, with only 1.2 cm2of the rectifier-antenna area.}