A CMOS RF-to-DC Power Converter With 86% Efficiency and-19.2-dBm Sensitivity

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 m standard CMOS technology and occupies an area of 8800 mu m(2). The measurement results show an 86% PCE and -19.2-dBm (12 mu W) sensitivity when operating at the medical band 433 MHz with a 100-k Omega load. Furthermore, the PCE is 66%, and the sensitivity is -18.2 dBm (15.1 mu W) when operating at UHF 900 MHz with a 100-k Omega load.