Wireless Energy Transfer Using Negative Index Metamaterials
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Solution Overview
Problem
Existing wireless energy transfer systems using resonant coupling have limited range and efficiency due to the distance-dependent attenuation of electromagnetic fields, restricting energy transfer to within a few times the characteristic size of the resonant source, and decreasing efficiency with increased distance between the source and sink.
Innovation Solution
A network of relay nodes arranged in the neighborhood of the source and sink, utilizing electromagnetic resonant structures that can transition between resonant and non-resonant modes to amplify evanescent waves, facilitated by a communication network to optimize energy transfer through negative index materials, allowing for extended range and improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If resonant coupling is used to transfer energy wirelessly, then energy transfer is achieved over mid-range distance, but the range is limited to about 3 to 8 times the characteristic size of the resonant source and efficiency decreases with distance
Solution Approach 1:
The patent introduces negative index materials as intermediary substances between the resonant source and sink to enhance evanescent wave coupling. These materials have unique electromagnetic properties that allow them to concentrate and amplify evanescent fields, effectively mediating the energy transfer process and extending the usable range while maintaining efficiency.
Solution Approach 2:
The patent changes the electromagnetic parameters of the transmission medium by using negative index materials with negative permittivity and permeability. This parameter change fundamentally alters how evanescent waves propagate, allowing for enhanced coupling over distances beyond the traditional 3-8 times characteristic size limit while maintaining high transfer efficiency.
2Length of stationary object
If the distance between source and sink is increased, then energy transfer range is extended, but induction method becomes highly ineffective
Solution Approach 1:
The patent employs negative index materials as composite materials that combine unique electromagnetic properties not found in conventional materials. These composite materials create a transmission medium that maintains strong evanescent wave coupling over extended distances, making the energy transfer reliable even when the distance between source and sink exceeds traditional limits.
3Reliability
If resonant objects with high quality factor are selected to optimize coupling, then coupling strength is improved, but the solution is limited to particular resonant system designs
Solution Approach 1:
The patent makes the coupling enhancement solution universal by using negative index materials that can be integrated with various resonant system designs. Rather than requiring specific high quality factor resonant objects, the negative index material provides a general mechanism for enhancing evanescent wave coupling that can be applied across different resonant system configurations and frequencies.
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
Enables wireless energy transfer over a significantly increased distance by amplifying evanescent waves, maintaining high efficiency through strategic mode transitions and relay node communication, thereby overcoming the limitations of conventional resonant coupling systems.
Implementation Method 1
During the coupling of the resonant objects, evanescent waves 130 are propagated between the resonant source and the resonant sink
Implementation Method 2
two resonant electromagnetic objects, i.e., the source and the sink, interact with each other under resonance conditions
Implementation Method 3
a source, e.g., primary coil, generates energy as an electromagnetic field
Implementation Method 4
Wireless Energy Transfer with Negative Index Material
Data Source
AI summary
A system includes a structure configured to exchange the energy wirelessly via a coupling of evanescent waves. The structure is non-radiative, and generates an electromagnetic (EM) near-field in response to receiving the energy. The structure is configured to exchange the energy when the structure is in the resonant mode. The system also includes a tuning module configured to transition the structure in and out of the resonant mode based on an instruction, an energy monitor module configured to determine the instruction based on information indicative of the energy stored and/or exchange by the structure, and a transceiver configured to transmit and/or to receive the instruction.