Ubiquitous Internet-of-Everything (IoE) applications require low-cost, miniature sensors with long lifetimes. Wirelessly-powered ICs that harvest energy from an RF beacon or from existing wireless signals can address challenges associated with battery size, capacity and replacements [1-5]. Given FCC transmit power limits, the operating range of wirelessly-powered sensors is limited by rectifier sensitivity rather than by communication link budgets. In this work, we present area-constrained antenna-rectifier architectures that leverage electrically-small antennas and rectifier circuits to achieve -34.5dBm sensitivity for 1.6V output with 1.8MΩ load (CC topology) and -24dBm sensitivity for 2.5V output with 100KΩ load (CP topology), representing a >5× improvement in sensitivity (>2× improvement in range) over current state-of-the-art and >1V output voltage [1]. Notably, this improvement is obtained even for cold-start with the typical rectifier storage capacitor as the only off-chip component, resulting in a very compact 1.2cm2 complete 2.4GHz antenna-rectifier system area.
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