ULP Beamforming WPT Using Backscatter Phase-Offset Correction
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Solution Overview
Problem
Current wireless power transfer (WPT) systems face inefficiencies due to high power consumption, large size, and high cost, particularly in mobile and remote applications where precise phase and frequency alignment of RF energy transmitters is challenging, leading to reduced energy transfer efficiency.
Innovation Solution
A closed-loop RF beamforming WPT system using ultra-low power (ULP) received power sensing and backscattering communication to correct phase and frequency offsets among RF energy transmitters, combined with a high-efficiency RF-to-DC conversion using a self-biased gate rectifier and maximum power tracking circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If channel sensing methods (RSSI or CSI) are used for closed loop beamforming optimization, then beamforming accuracy is improved, but power consumption increases to 10s of mW
Solution Approach 1:
The patent extracts only the essential function of power sensing from the complex RSSI/CSI sensing circuits, implementing a simplified power detection mechanism that measures only the received power magnitude without requiring full channel state information or baseband processing capabilities. This selective extraction of the necessary sensing function reduces power consumption while maintaining beamforming accuracy.
Solution Approach 2:
The system enables the receiver to self-determine the optimal beamforming configuration by sensing received power and providing feedback to transmitters. The receiver autonomously performs power measurement and communicates results back to the transmitter array, eliminating the need for high-power active sensing at the receiver end while maintaining closed-loop optimization capability.
2Adaptability or versatility
If frequent updates of CSI or RSSI values are performed to track channel variations, then beamforming adaptability is improved, but power consumption and processing requirements increase
Solution Approach 1:
The system implements periodic power sensing and feedback updates at optimized intervals rather than continuous monitoring. The receiver performs power measurements at predetermined time intervals and sends feedback packets accordingly, maintaining beamforming adaptability to channel variations while significantly reducing the average power consumption compared to continuous sensing and updating.
3Ease of operation
If RF-to-DC conversion is performed at the receiver, then wireless power transfer is enabled, but conversion efficiency is reduced
Solution Approach 1:
The system implements a closed-loop feedback mechanism where the receiver senses the received RF power level and communicates this information back to the transmitters. The transmitters use this feedback to adjust their beamforming parameters and transmit power levels, optimizing the RF power delivery to the receiver and thereby improving the overall RF-to-DC conversion efficiency by ensuring the receiver operates at its optimal power reception point.
Solution Approach 2:
The system performs preliminary beamforming optimization and power level adjustment before the actual RF-to-DC conversion process. By pre-aligning the transmitter beams and setting appropriate power levels based on initial power sensing, the system ensures that the RF energy arriving at the receiver is already optimized for efficient conversion, reducing energy losses during the conversion process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution achieves a significant reduction in power overhead, cost, and size, enabling efficient energy transfer with a 5-orders of magnitude power reduction, and maintains high efficiency (40-70%) for RF-to-DC conversion, suitable for mobile and remote applications.
Implementation Method 1
converting the RF energy output from the RF energy transmitters to direct current
Implementation Method 2
backscattering communication method is used to lower the power, cost, and size associated with closed loop beamforming
Data Source
AI summary
Wireless power transfer (WPT) efficiency is enhanced using an ultra-low power (ULP) distributed beamforming technique. A phase and frequency offset correction technique is used for beam-forming optimization, a backscattering communication technique is used to reduce power over-head, and a new rectifier and MPT method is used for high efficiency RF-to-DC conversion.