Negative Index Material Enhancing Evanescent Wave Coupling
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Solution Overview
Problem
Current wireless energy transfer technologies, such as inductive and resonant coupling, face inefficiencies due to the attenuation of electromagnetic fields over distance, limiting the effective range and efficiency of energy transfer between source and sink.
Innovation Solution
Incorporating negative refractive index material along the path of evanescent wave coupling to enhance the amplitude of evanescent waves, thereby optimizing the efficiency of wireless energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If resonant coupling is used to transfer energy wirelessly over mid-range distances, then the energy transfer distance is improved, but the coupling efficiency deteriorates due to field attenuation
Solution Approach 1:
The patent introduces negative index material (NIM) as an intermediary substance placed between the source and sink to enhance evanescent wave coupling. The NIM acts as a mediator that amplifies the evanescent fields, allowing efficient energy transfer over extended distances without direct contact between source and sink.
Solution Approach 2:
The patent changes the electromagnetic parameters of the medium by introducing negative index material with negative permittivity and permeability. This parameter change transforms the propagation characteristics of evanescent waves, converting exponentially decaying fields into amplified or sustained fields that maintain coupling efficiency over longer distances.
2Length of stationary object
If the distance between source and sink is increased beyond resonant coupling range, then the operational range is improved, but the energy transfer effectiveness deteriorates due to high attenuation
Solution Approach 1:
Negative index material serves as a mediator that bridges the gap between source and sink when they are separated beyond conventional resonant coupling distances. The NIM sustains and amplifies evanescent waves across this extended gap, maintaining effective coupling despite the increased separation.
Solution Approach 2:
The patent employs composite negative index materials composed of metamaterial structures with engineered electromagnetic properties. These composite materials provide the necessary negative permittivity and permeability to enhance evanescent wave coupling over extended distances, combining multiple material properties to achieve the desired effect.
3Device complexity
If conventional materials are used for coupling, then the system simplicity is maintained, but the coupling coefficient and energy transfer efficiency are limited
Solution Approach 1:
The patent introduces composite negative index materials with engineered metamaterial structures to achieve negative permittivity and permeability. These composite materials enable enhanced evanescent wave coupling and improved energy transfer efficiency, overcoming the limitations of conventional materials while maintaining practical system implementation.
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 use of negative index material significantly increases the coupling coefficient and efficiency of energy transfer, allowing for more effective wireless energy exchange over longer distances and varying frequencies, as demonstrated by enhanced energy transfer efficiency graphs and tables.
Implementation Method 1
a source, e.g., primary coil, generates energy as an electromagnetic field, and a sink, e.g., a secondary coil, subtends that field
Implementation Method 2
Incorporating negative refractive index material along the path of evanescent wave coupling to enhance the amplitude of evanescent waves
Implementation Method 3
In resonant coupling, two resonant electromagnetic objects, i.e., the source and the sink, interact with each other under resonance conditions
Implementation Method 4
a source, e.g., primary coil, generates energy as an electromagnetic field, and a sink, e.g., a secondary coil, subtends that field such that the energy passing through the sink is optimized
Data Source
AI summary
A system exchanges energy wirelessly and 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. A negative index material (NIM) is arranged within the EM near-field such that the coupling is enhanced.