Dualband Flexible Antenna with Segmented Impedance Surface

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Solution Overview

Problem

Modern vehicles face challenges in antenna placement due to increasing numbers of antennas required for various communication systems, leading to design and styling issues, and existing antennas mounted on dielectric substrates like vehicle glass suffer from surface waves that reduce efficiency and performance by causing scattering and energy loss.

Innovation Solution

A dual-band WiFi CPW antenna structure with a frequency selective impedance surface, including a semi-circular segmented ring surrounding the antenna, is designed to mitigate surface waves by converting them into leaky-wave radiation, allowing flexible mounting on vehicle glass without interfering with visibility and maintaining efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an antenna is flush mounted to a thick dielectric substrate like vehicle glass, then the antenna can be integrated into the vehicle structure and placed in visible areas, but surface waves are generated that cause scattering and reduce antenna efficiency and gain

Engineering Contradiction:

Improveantenna placement flexibilityVSAvoidantenna efficiency

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

A frequency selective surface (FSS) is introduced as an intermediary element between the antenna and the dielectric substrate. This FSS acts as a mediator that selectively interacts with surface waves at specific frequencies, allowing the antenna to maintain efficient operation while being flush-mounted to the glass substrate. The FSS structure enables the antenna to place in visible areas without suffering from surface wave losses.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If multiple antennas are mounted on the vehicle roof to support various communication systems, then communication coverage is improved, but the size of housing structures increases and interferes with vehicle design and styling

Engineering Contradiction:

Improvecommunication coverageVSAvoidhousing structure size

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The antenna is designed as a thin, flexible printed structure that can be directly applied to the curved surface of vehicle glass. This eliminates the need for bulky traditional antenna housings and mounting structures. The flexible printed antenna conformally attaches to the glass surface, maintaining communication performance while preserving vehicle design and styling.

Inventive Principle:

Principle #30Flexible shells and thin films

3Adaptability or versatility

If the antenna operates at WiFi frequencies (2.4 GHz and 5.8 GHz) on standard thickness glass (3-5 mm), then the antenna can be mounted on typical vehicle windshields, but the glass becomes electrically thick at these frequencies causing surface wave generation

Engineering Contradiction:

Improvecompatibility with standard glassVSAvoidsurface wave scattering

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The frequency selective surface is designed with specific local geometric properties that are optimized for each operating frequency band. The FSS contains periodic structures with dimensions and spacing tailored to create frequency-selective behavior at 2.4 GHz and 5.8 GHz. This local optimization allows the antenna system to operate effectively on standard thickness glass without surface wave interference at the target frequencies.

Inventive Principle:

Principle #3Local quality

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 effectively reduces surface wave effects, enhancing antenna efficiency and gain while allowing flexible placement on vehicle glass, including visible areas, without compromising design or performance.

Implementation Method 1

surface waves propagating along the dielectric substrate generated by the antenna

Methodology Applied

Scientific EffectSurface waves: Surface Acoustic Wave

Implementation Method 2

the frequency selective impedance ring receives surface waves propagating along the dielectric substrate generated by the antenna

Methodology Applied

Scientific EffectLeaky-wave radiation:

Data Source

PatentUS10530036B2Dualband flexible antenna with segmented surface treatment

Publication Date: 2020.01.07 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

An antenna structure including a dual-band WiFi CPW antenna formed on a dielectric substrate and a frequency selective impedance surface formed on the substrate and at least partially surrounding the antenna. The antenna includes a ground plane defining a gap and an antenna radiating element including a radiating portion positioned proximate to the ground plane and a feed line extending into the gap. The frequency selective impedance surface can be a ring that is configured around the radiating portion of the radiating element, where the frequency selective impedance ring receives surface waves propagating along the dielectric substrate generated by the antenna.