Transparent RF Devices on Glass Using Silver Nanowire and Graphene

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Solution Overview

Problem

Current technologies lack the ability to integrate optically transparent active and passive RF devices, such as antennas, effectively onto or into surfaces like glass, which is essential for efficient RF-based systems in vehicles and aircraft due to space constraints and design limitations.

Innovation Solution

The integration of silver nanowire (Ag NW) films as transparent conductors and graphene films as active channel materials for forming optically transparent RF devices, including antennas and circuits, onto glass substrates, enabling reconfigurable and efficient RF systems that can be used in vehicles, aircraft, and other structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If traditional opaque antenna designs are used, then antenna functionality is achieved, but optical transparency is lost and space requirements increase

Engineering Contradiction:
Improveoptical transparencyVSAvoidantenna functionality
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent employs composite material structures combining transparent conductive oxides (such as ITO, IZO, or AZO) with dielectric layers to create antenna elements that simultaneously achieve optical transparency and RF functionality. This composite approach allows the antenna to maintain both transparency and electromagnetic performance

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent utilizes plasma treatment to modify surface parameters of the substrate and conductive layers, enhancing adhesion and electrical properties without compromising optical transparency. The plasma process changes surface energy and morphology to improve device performance while maintaining transparency

Inventive Principle:
Principle #35Parameter changes

2Area of stationary object

If antenna space is reduced to meet design constraints, then space efficiency improves, but manufacturing precision becomes more difficult to achieve

Engineering Contradiction:
Improveantenna spaceVSAvoidfabrication accuracy
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent divides the antenna structure into multiple functional layers (conductive layers, dielectric layers, patterned elements) that can be fabricated separately and precisely assembled. This segmentation allows each layer to be optimized and controlled independently, improving overall manufacturing precision in compact designs

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces plasma treatment as an intermediary process between substrate preparation and antenna fabrication. This plasma step acts as a mediator that enhances surface properties and adhesion, enabling more precise fabrication of miniaturized antenna structures

Inventive Principle:
Principle #24Intermediary (Mediator)

3Illumination intensity

If transparent conductive materials are used, then optical transparency is maintained, but conductivity is reduced compared to traditional metals

Engineering Contradiction:
Improveoptical transparencyVSAvoidelectrical conductivity
Core Design Contradiction:
Illumination intensityVSPower

Solution Approach 1:

The patent creates composite conductive structures combining transparent conductive oxides with metallic nanoparticles or interdigitated electrode patterns. This composite approach compensates for the lower conductivity of transparent materials while preserving optical transparency

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent employs plasma treatment and annealing processes to modify the electrical parameters of transparent conductive materials, reducing their sheet resistance and improving conductivity without affecting their optical transparency properties

Inventive Principle:
Principle #35Parameter changes

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 allows for the creation of optically transparent RF front ends with enhanced conductivity and flexibility, enabling efficient antenna design and operation on glass surfaces, reducing thermal load, and providing design flexibility for RF systems while maintaining optical transparency.

Implementation Method 1

silver nanowire (Ag NW) films as transparent conductors

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

silver nanowire (Ag NW) films as transparent conductors

Methodology Applied
Scientific EffectOptical transparency:

Implementation Method 3

graphene films as active channel materials

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 4

optically transparent passive electromagnetic structures, such as antennas

Methodology Applied
Scientific EffectElectromagnetic radiation:

Data Source

PatentEP2929545B1Forming transparent devices on surfaces
Publication Date: 2020.09.23 HRL LAB
  • EP2929545B1 patent drawingFigure 1
  • EP2929545B1 patent drawingFigure 2(a)~2(d)
  • EP2929545B1 patent drawingFigure 3(a)~3(c)

AI summary

An apparatus, system, and/or method are described to enable optically transparent reconfigurable integrated electrical components, such as antennas and RF circuits to be associated with an optically transparent host platform, such as glass. In one embodiment, an Ag NW film may be configured as a transparent conductor for antennas and/or as interconnects for passive circuit components, such as capacitors or resistors. Ag NW may also be used as transmission lines and/or interconnect overlays for devices. A graphene film may also be configured as active channel material for making active RF devices, such as amplifiers and switches.