Window Glass Antenna Unit With Permittivity-Matched Wave Director

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Solution Overview

Problem

Flat antennas experience a decrease in Front-to-Back (FB) ratio due to electromagnetic wave reflection when window glass with high relative permittivity is present, leading to reduced radiation efficiency.

Innovation Solution

An antenna unit is attached to window glass with a wave directing member positioned between the window glass and the radiating element, optimizing the distance and relative permittivity to minimize reflections and enhance directivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If window glass with high relative permittivity is placed in front of the antenna, then the antenna can be attached to the window glass, but electromagnetic wave reflection increases causing FB ratio to decrease

Engineering Contradiction:

Improveantenna attachment to window glassVSAvoidFB ratio

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

A matching body with intermediate relative permittivity is introduced between the antenna and the window glass. The matching body's permittivity is lower than the window glass but higher than air, creating a gradual transition that reduces reflection. This intermediary layer acts as a impedance matcher, allowing the antenna to be attached to the window glass while maintaining acceptable FB ratio performance.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If the antenna radiates electromagnetic waves in the front direction, then radiation efficiency is improved, but reflection at the window glass interface increases back radiation

Engineering Contradiction:

Improveradiation efficiencyVSAvoidback radiation

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The reflection that would normally cause harmful back radiation is converted into a useful function by the matching body. The matching body absorbs and redirects the reflected energy, converting what would be harmful back radiation into forward-directed radiation or absorbed energy, thereby improving overall radiation efficiency while reducing back radiation.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 solution improves the FB ratio by reducing electromagnetic wave reflections at the window glass interface, increasing the gain of the main lobe while reducing side lobe radiation, thereby enhancing the antenna's radiation efficiency.

Implementation Method 1

electromagnetic waves are reflected at the interface of the window glass 200

Methodology Applied

Scientific EffectElectromagnetic wave reflection: Reflection

Implementation Method 2

window glass having a relatively high relative permittivity

Methodology Applied

Scientific EffectRelative permittivity: Dielectric Permittivity

Data Source

PatentEP3767745B1Antenna unit, and antenna unit-attached window glass

Publication Date: 2023.11.29 AGC INC

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AI summary

An antenna unit used by being attached to window glass for a building includes a radiating element, a wave directing member arranged on an outdoor side with respect to the radiating element, and a conductor arranged on an indoor side with respect to the radiating element, wherein where a distance between the radiating element and the wave directing member is denoted as a, and where a relative permittivity of a medium constituted by a dielectric member between the radiating element and the wave directing member is denoted as εr, the distance a is (2.11 × εr - 1.82) mm or more.