A self-biased, cross-coupled, differential rectifier is proposed with enhanced power-conversion efficiency over an extended range of input power. A prototype is designed for UHF 433MHz RF power-harvesting applications and is implemented using 0.18µm CMOS technology. The proposed rectifier architecture is compared to the conventional cross-coupled rectifier. It demonstrates an improvement of more than 40% in the rectifier power conversion efficiency (PCE) and an input power range extension of more than 50% relative to the conventional crosscoupled rectifier. A sensitivity of-15.2dBm (30µW) input power for 1V output voltage and a peak power-conversion efficiency of 65% are achieved for a 50kΩ load.

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

A wide-range, differential, cross-coupled rectifier is proposed with an extended dynamic range of input RF power that enables wireless powering from varying distances. The proposed architecture mitigates the reverse-leakage problem in conventional, cross-coupled rectifiers without degrading sensitivity. A prototype is designed for UHF RFID applications, and is implemented using 0.18 μm CMOS technology. On-chip measurements demonstrate a sensitivity of -18 dBm for 1 V output over a 100 kΩ load and a peak RF-to-DC power conversion efficiency of 65%. A conventional, fully cross-coupled rectifier is fabricated alongside for comparison and the proposed rectifier shows more than 2× increase in dynamic range and a 25% boosting in output voltage than the conventional rectifier

A first fully integrated 5.2-GHz CMOS-based RF power harvester with an on-chip antenna is presented in this paper. The design is optimized for sensors implanted inside the eye to wirelessly monitor the intraocular pressure of glaucoma patients. It includes a five-stage RF rectifier with an on-chip antenna, a dc voltage limiter, two voltage sensors, a low dropout voltage regulator, and MOSCAP based on-chip storage. The chip has been designed and fabricated in a standard 0.18-m CMOS technology.To emulate the eye environment in measurements, a custom test setup is developed that comprises Plexiglass cavities filled with saline solution. Measurements in this setup show that the proposed chip can be charged to 1 V wirelessly from a 5-W transmitter 3 cm away from the harvester chip. The energy that is stored on the 5-nF on-chip MOSCAP when charged to 1 V is 2.5 nJ, which is sufficient to drive an arbitrary 100-W load for 9 s at regulated 0.8 V. Simulated efficiency of the rectifier is 42% at 7 dBm of input power.

No abstract