A technology that improves the dynamic range of rectifiers and detectors in RF-to-DC conversion applications, power sensing and measurement devices, wireless power transfer (WPT) systems, and wireless power harvesting (WPH) systems has been developed at the University of Michigan. WPT and WPH systems suffer from limited dynamic range (the input power range where the rectifier can maintain a high level of efficiency). Since rectifier efficiency determines overall system efficiency, and since the aforementioned systems typically operate under fluctuating RF power levels, maintaining rectifier efficiency over a large input power variation is a challenge.
The University of Michigan technology to improve the dynamic range of rectifiers and detectors leverages an extended resonance network to achieve adaptive power steering and impedance compression. The idea takes advantage of the nonlinear input impedance of the rectifiers to achieve adaptive power steering—the adaptive power steering network distributes RF power among different rectifier cells according to their relative impedance values. As a result, at low RF power levels, a major portion of the RF power is directed to the rectifiers optimized for low power operation; while at high RF power levels, a major portion of the RF power is directed to rectifiers optimized for high power operation, thereby improving rectification efficiency. Since only the proper rectifier cells are excited, the total input impedance variation is reduced, thereby reducing power loss due to mismatch reflection and fluctuating power levels. Overall, the system is scalable, does not involve quiescent power consumption, and effectively enhances the dynamic range of rectifiers. Further, the system demonstrates low cost, low complexity, high reliability, and feasibility for mass production.
- Wireless power transfer and harvesting
- Power amplifier applications
- Power sensing detectors
- Wind power turbine applications
- No quiescent power consumption
- Low cost
- Reduced complexity
- High reliability
- Feasible for mass production