Retrodirective Array Wireless Power Transmission
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Solution Overview
Problem
Existing wireless power transmission systems are inefficient in illuminating multiple dispersed wireless power receivers, as broad-beam illumination wastes power and narrow-beam illumination fails to deliver power to receivers outside the beam width, leading to suboptimal efficiency and power distribution.
Innovation Solution
A switched-beam wireless power transmission system using a retrodirective array (RDA) that sequentially illuminates multiple receivers with a single narrow RF beam, where each receiver is equipped with a beacon transmitting a pilot signal, allowing the RDA to electronically steer and amplify the beam to optimize power delivery to each receiver, thereby increasing power density and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If broad-beam illumination is used to illuminate all receivers simultaneously, then all receivers can receive power at the same time, but most of the radiated power falls between the receivers and is wasted, resulting in low efficiency
Solution Approach 1:
The patent divides the broad-beam illumination into multiple separate narrow beams, each targeted at a specific receiver. The transmitting antenna system generates individual beams that are spatially segmented to illuminate only the intended receivers, eliminating wasted power in inter-receiver spaces.
Solution Approach 2:
The patent applies different beam characteristics to different spatial locations. Each receiver receives a dedicated narrow beam with concentrated power, while areas between receivers receive minimal or no power. This local optimization ensures high power density at receiver locations without wasting energy elsewhere.
2Loss of energy
If narrow-beam illumination is used to efficiently illuminate a single receiver, then power delivery efficiency to that receiver is high, but very little power is delivered to receivers outside the beam width
Solution Approach 1:
The patent employs dynamic beam steering capabilities where the narrow beams can be electronically redirected to different receivers. The system adjusts beam directions and positions in real-time to track and illuminate multiple receivers sequentially or simultaneously, maintaining high efficiency while serving multiple targets.
Solution Approach 2:
The patent uses periodic switching between different narrow beams to illuminate different receivers. Each receiver receives concentrated power during its designated time interval, and the system cycles through multiple receivers, achieving both high efficiency for each receiver and the ability to serve multiple receivers overall.
3Adaptability or versatility
If a large phased array antenna is used to beam power to multiple receiving sites simultaneously, then multiple receivers can be illuminated, but many array elements must operate at less than full output power, reducing overall system efficiency
Solution Approach 1:
The patent segments the power transmission task by assigning dedicated array elements or element groups to specific receivers. Instead of distributing power across all elements for all receivers simultaneously, each receiver is served by a subset of elements operating at full power, while other elements remain inactive or serve different receivers at different times.
Solution Approach 2:
The patent uses partial activation of array elements for each transmission cycle. Only the necessary number of elements required to illuminate the current target receiver(s) are activated at full power, rather than operating all elements. This partial action maintains high efficiency while achieving multi-receiver coverage through sequential or selective illumination.
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
The system achieves significantly higher power density and efficiency by electronically steering the beam to each receiver, minimizing energy loss between them and ensuring consistent power delivery, even when receivers are dispersed or moving, thus overcoming the limitations of traditional methods.
Implementation Method 1
Each receiver includes phase conjugating circuitry that extracts the phase from the pilot signal at the pilot signal frequency and forms a conjugated signal at the illumination frequency
Implementation Method 2
Each element of the RDA radiates an amplified beam whose polarization is substantially the same as that radiated by all other elements
Implementation Method 3
the amplified signals combine in phase or collectively accumulate to yield an electromagnetic field whose amplitude is about, or nearly, N times greater than the electromagnetic field generated by a single element
Data Source
Figure 1~3
Figure 4
Figure 5A~5C
AI summary
A wireless power transmission system including at least one source of electromagnetic radiation, a plurality of wireless power receivers that receive radiated electromagnetic energy, a beacon collocated with each wireless power receiver, wherein the beacon generates and radiates a pilot signal when the beacon is in an active state, and an array of transmitting antennas connected to the source of electromagnetic radiation that radiates the electromagnetic radiation in the direction of the beacon in the active state. The electromagnetic radiation can be electronically steered from one wireless power receiver to another by activating and deactivating the beacons collocated with each wireless power receiver.