Doped Graphene Electromagnetic Shielding
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Solution Overview
Problem
Current electromagnetic shielding materials are heavy, non-transparent, and offer limited mechanical strength, making them unsuitable for many applications, and existing transparent materials have low shielding effectiveness and require increased thickness to improve performance.
Innovation Solution
Doped graphene sheets are used, either alone or on a flexible substrate, to reflect or absorb electromagnetic radiation at frequencies greater than 1 megahertz, providing effective shielding with minimal weight and increased versatility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metallic films or grids are used for electromagnetic shielding, then shielding effectiveness is improved, but weight increases significantly
Solution Approach 1:
The patent changes the material parameter from traditional metals to graphene, which has exceptional strength-to-weight ratio. The graphene-based shield achieves comparable or superior shielding effectiveness while reducing weight by using carbon atoms arranged in a two-dimensional hexagonal lattice structure with inherent high strength and low density.
Solution Approach 2:
The patent employs composite material structures by combining graphene layers with substrate materials or other functional layers. This composite approach allows optimization of both shielding effectiveness and weight, creating a lightweight yet highly effective electromagnetic shield that overcomes the limitations of pure metallic shields.
2Illumination intensity
If conventional transparent materials like ITO or ZnO are used for EM shielding, then transparency is improved, but shielding effectiveness decreases
Solution Approach 1:
The patent changes the material parameter from conventional transparent conductive oxides to graphene, which offers superior electrical conductivity and carrier mobility. This parameter change enables graphene to achieve high shielding effectiveness while maintaining transparency, as the two-dimensional structure allows light transmission while the high conductivity provides effective EM wave reflection and absorption.
Solution Approach 2:
The patent substitutes the mechanical/physical structure of thick transparent conductive oxide layers with a two-dimensional graphene structure. This substitution eliminates the need for increased thickness to improve shielding, as graphene's atomic-level thickness combined with high conductivity provides superior shielding performance while maintaining optical transparency.
3Illumination intensity
If transparent EM shield materials are used, then transparency is improved, but mechanical strength decreases
Solution Approach 1:
The patent employs composite material structures by integrating graphene layers with substrate materials or support structures. This composite approach combines the transparency of thin films with the mechanical strength of supporting structures, creating a transparent shield that maintains both optical properties and structural integrity.
Solution Approach 2:
The patent changes the material parameter from fragile transparent conductive oxides to graphene, which possesses exceptional intrinsic mechanical strength. Graphene's two-dimensional honeycomb lattice structure provides outstanding tensile strength and flexibility, enabling transparent shields with superior mechanical properties that can withstand bending, stretching, and environmental stress.
4Reliability
If increased thickness is used to improve shielding effectiveness with transparent materials, then shielding effectiveness is improved, but transparency decreases
Solution Approach 1:
The patent changes the fundamental material parameter from thick transparent conductive oxides to ultra-thin graphene layers. This parameter change reverses the traditional trade-off by achieving high shielding effectiveness at atomic-level thickness. Graphene's high electrical conductivity and two-dimensional structure enable effective EM wave interaction without requiring increased thickness, thereby maintaining superior optical transparency.
Solution Approach 2:
The patent substitutes the thickness-based shielding mechanism of conventional materials with a conductivity-based mechanism in graphene. Instead of relying on thick layers to attenuate EM waves, the graphene shield uses its high electrical conductivity and two-dimensional electron gas to reflect and absorb EM waves effectively at minimal thickness, preserving optical transparency.
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 doped graphene sheets offer significant electromagnetic interference shielding with broadband capabilities, high mechanical strength, and transparency, achieving shielding effectiveness of over 40 decibels with a thickness of only a few nanometers, addressing the limitations of existing materials.
Implementation Method 1
at least one of the graphene sheets is doped with a dopant having a dopant concentration in an amount effective to reflect electromagnetic radiation at frequencies greater than 1 megahertz
Implementation Method 2
Doped graphene sheets are used, either alone or on a flexible substrate, to reflect or absorb electromagnetic radiation at frequencies greater than 1 megahertz
Implementation Method 3
at least one of the graphene sheets is doped with a dopant having a dopant concentration in an amount effective to absorb electromagnetic radiation at frequencies greater than 1 megahertz
Data Source
AI summary
Electromagnetic interference shielding structures and methods of shielding an object form electromagnetic radiation at frequencies greater than a megahertz generally include providing highly doped graphene sheets about the object to be shielded. The highly doped graphene sheets may have a dopant concentration greater than >1e1013 cm−2, which is effective to reflect the electromagnetic radiation or a dopant concentration of 1e1013 cm−2>n>0 cm−2, which is effective to absorb the electromagnetic radiation.