Antenna Isolation via Tuned Ground Plane Notch

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Solution Overview

Problem

Antennas in close proximity to each other in portable devices experience performance degradation due to electromagnetic interference, which is not adequately addressed by existing technologies, limiting the effectiveness of MIMO and diversity techniques for improving signal quality and data transmission rates.

Innovation Solution

The solution involves forming a notch in the edge of a conductive groundplane between antennas, with a capacitive component at the notch's mouth to tune the inductance, creating a resonant circuit that enhances isolation between antennas without significant efficiency loss, and allowing for adjustable resonant frequency and bandwidth through additional components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If antennas are disposed in close proximity to each other in portable devices, then device compactness is improved, but antenna isolation deteriorates leading to electromagnetic interference

Engineering Contradiction:
Improvedevice compactnessVSAvoidelectromagnetic interference
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

A notch structure is introduced as an intermediary element between the two antennas on the ground plane. This notch acts as a mediator that disrupts the electromagnetic coupling paths between antennas, providing isolation while allowing the antennas to remain in close proximity for compact device design

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The ground plane geometry is modified by creating a notch with specific dimensions (width, depth, and position). By changing the geometric parameters of the ground plane in the region between antennas, the electromagnetic field distribution is altered to reduce coupling and improve isolation between closely-spaced antennas

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If isolation structures are added between antennas, then antenna isolation is improved, but device complexity increases

Engineering Contradiction:
Improveantenna isolationVSAvoidground plane structure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The ground plane is segmented by introducing a notch that divides the continuous conductive surface. This segmentation creates separate electromagnetic zones between the antennas, providing isolation while maintaining the overall simplicity of the ground plane structure as a single integrated component

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The ground plane is modified locally in the specific region between the antennas by creating a notch. The rest of the ground plane maintains its original continuous structure, so the isolation improvement is achieved through localized modification rather than global structural complexity

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

This configuration significantly improves antenna isolation, enabling effective MIMO and diversity operations by maintaining high efficiency and broadening the bandwidth of the isolation effect, even at close antenna spacings, thus enhancing signal quality and data transmission rates.

Implementation Method 1

the mouth of the notch is provided with at least one capacitive component that serves to tune an inductance of the edge of the conductive groundplane in the notch so as to improve isolation between the first and second antennas

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

two or more antennas operating on similar frequencies in close proximity to each other... electromagnetic interference

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Data Source

PatentEP2826098B1Antenna isolation using a tuned ground plane notch
Publication Date: 2019.11.27 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP2826098B1 patent drawingFigure 1~3
  • EP2826098B1 patent drawingFigure 2~4
  • EP2826098B1 patent drawingFigure 5~6

AI summary

There is disclosed an antenna device relating to a single or dual band antenna system for use in mobile telecommunications devices, laptop and tablet computers, USB adapters and electrically small radio platforms comprising a pair of antennas attached to a conductive ground plane, the antennas being separated by free space in which at least one notch is formed in the conductive ground plane between the pair of antennas characterised in that the notch further includes an inductive component and a capacitive component providing good antenna isolation so as to enable MIMO operation or diversity operation.