Abstract
This paper proposes an RF-to-dc power converter for ambient wireless powering that is efficient, highly sensitive, and less dependent on the load resistance with an extended dynamic range. The proposed rectifier utilizes a variable biasing technique to control the conduction of the rectifying transistors selectively, hence minimizing the leakage current; unlike the prior work that has a fixed feedback resistors, which limits the efficient operation to a relatively high RF power and causes a drop in the peak power conversion efficiency (PCE). The proposed design is fabricated using a 0.18- \mu \text{m} standard CMOS technology and occupies an area of 8800~\mu \text{m}^{2} . The measurement results show an 86% PCE and −19.2-dBm ( 12~\mu \text{W} ) sensitivity when operating at the medical band 433 MHz with a 100- \text{k}\Omega load. Furthermore, the PCE is 66%, and the sensitivity is −18.2 dBm ( 15.1~\mu \text{W} ) when operating at UHF 900 MHz with a 100- \text{k}\Omega load.