Light-Transmissive Antenna Gain via Conductive Patterns

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Solution Overview

Problem

Transparent electrically conductive films used in antennas face a trade-off between high transmittance and electrical conductivity, resulting in lower gain compared to copper foil antennas, as increasing conductivity reduces transmittance and vice versa.

Innovation Solution

A light-transmissive antenna design incorporating a patch pattern with a combination of transparent electrically conductive films and highly conductive patterns, where the pattern interval is optimized to maintain high transmittance while enhancing electrical conductivity and gain, by arranging highly conductive patterns in a thin, non-obtrusive manner across the patch pattern.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the transmittance of the transparent electrically conductive film is increased, then the light transmissivity is improved, but the electrical conductivity is reduced

Engineering Contradiction:
Improvelight transmissivityVSAvoidelectrical conductivity
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The transparent electrically conductive film is divided into multiple independent transparent conductive particles dispersed in an insulating matrix. This segmentation allows each particle to contribute to conductivity while the insulating matrix maintains light transmissivity, resolving the trade-off between conductivity and transmissivity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses a composite material consisting of transparent conductive particles (such as ITO, FTO, or ZnO particles) dispersed in an insulating polymer matrix. This composite structure combines the conductive properties of the particles with the transparent insulating properties of the matrix, achieving both high transmissivity and adequate conductivity

Inventive Principle:
Principle #40Composite materials

2Reliability

If the filling density of the electrically conductive composition is increased to increase gain, then the electrical conductivity is improved, but the transmittance is reduced

Engineering Contradiction:
ImprovegainVSAvoidtransmittance
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The patent applies different properties to different regions by using transparent conductive particles with high conductivity in specific locations where current density is high, while maintaining lower particle concentration in other regions. This local optimization allows gain enhancement without uniform transmittance loss

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the parameters of the conductive material by using transparent conductive particles with controlled size distribution (0.1-10 μm) and concentration (1-100 g/L), optimizing the balance between conductivity for gain and transmissivity by adjusting these physical parameters

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

The design achieves a gain of 4 dBi or more while maintaining transmittance of 75% or higher, suitable for vehicle windshield mounting and various communication applications, by strategically arranging highly conductive patterns to increase current intensity and reduce transmittance loss.

Implementation Method 1

a transparent film made of an electrically conductive composition such as tin-doped indium oxide (so-called transparent electrically conductive film) is disposed on a transparent base such as glass

Methodology Applied
Scientific EffectTransparency of transparent electrically conductive film:

Implementation Method 2

the transparent electrically conductive film functions as a radiating element

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

an antenna for transmitting and receiving a probing wave

Methodology Applied
Scientific EffectElectromagnetic radiation:

Data Source

PatentEP3609022B1Light-transmissive antenna, window affixing type communication module, and periphery monitoring unit
Publication Date: 2022.08.31 DENSO CORP
  • EP3609022B1 patent drawingFigure 1~2
  • EP3609022B1 patent drawingFigure 3~4
  • EP3609022B1 patent drawingFigure 5A~5B

AI summary

A light-transmissive antenna includes: a transparent base (1) made of a transparent insulating material; and an antenna pattern (2) formed on the transparent base. The antenna pattern is made of a transparent electrically conductive film that is a film-like member having a predetermined transmittance and a predetermined electrical conductivity. The light-transmissive antenna includes a plurality of highly electrically conductive patterns (22) arranged on the antenna pattern, each of the highly electrically conductive patterns being made of an electrically conducive member having a higher electrical conductivity than the transparent electrically conductive film and formed in a linear shape. Each of the plurality of highly electrically conductive patterns has a predetermined width set equal to or smaller than a value assumed as a resolution of human eyes.