T-Shaped Isolator Bar for Antenna Array RF Isolation

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Solution Overview

Problem

Radio frequency coupling between antenna elements in modern wireless systems complicates the prediction of radiation patterns and maximum radiated power, as existing technologies struggle to achieve high isolation between antenna elements.

Innovation Solution

An antenna array assembly featuring an elongate isolator bar with a T-shaped cross-section, where the cross-piece is at least a quarter of a wavelength wide, providing radio frequency isolation between antenna elements, and optionally incorporating radiation absorbent material to reduce surface currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If antenna elements are placed close together to reduce array size, then device compactness is improved, but radio frequency coupling between elements increases causing unpredictable radiation patterns

Engineering Contradiction:
Improveantenna array sizeVSAvoidradiation pattern prediction accuracy
Core Design Contradiction:
Volume of moving objectVSDifficulty of detecting and measuring

Solution Approach 1:

An isolator bar is introduced as an intermediary component between adjacent antenna elements. This bar, having a T-shaped cross-section with a cross-piece width of at least a quarter wavelength at the operating frequency, acts as a electromagnetic field mediator that blocks coupling between elements while allowing the elements to remain in close proximity for compact array design.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Difficulty of detecting and measuring

If isolation structures are added between antenna elements to reduce coupling, then radiation pattern prediction accuracy is improved, but device complexity increases

Engineering Contradiction:
Improveradiation pattern prediction accuracyVSAvoidantenna array structure complexity
Core Design Contradiction:
Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The isolator bar's cross-piece width is designed based on a specific parameter relationship - at least a quarter of the wavelength at the operating frequency. This parameter-based design provides effective isolation while maintaining a compact and relatively simple structure that can be easily integrated into the antenna array.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If larger isolator cross-piece width is used to increase isolation, then isolation between antenna elements is improved, but device volume increases

Engineering Contradiction:
Improveradio frequency couplingVSAvoidisolator bar volume
Core Design Contradiction:
Object-affected harmful factorsVSVolume of moving object

Solution Approach 1:

The isolator bar's cross-piece width is designed based on a specific parameter relationship - at least a quarter of the wavelength at the operating frequency. This parameter-based design provides effective isolation while maintaining a compact and relatively simple structure that can be easily integrated into the antenna array.

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 configuration achieves high isolation between antenna elements, allowing for a more straightforward prediction of radiation patterns and maximum radiated power, with isolation values of 30 dB or greater, and reduces radiation due to surface currents.

Implementation Method 1

the isolator bar (lb) comprising: a support bar in contact with the ground plates of the first and second antenna elements, the support bar forming the stem of the T shape; and a substantially planar cross piece forming the top of the T shape and being disposed in a parallel relationship with the planes of the ground plates... whereby to provide radio frequency isolation between the first and second antenna elements

Methodology Applied
Scientific EffectRadio frequency isolation: Absorption (EM radiation)

Data Source

PatentEP3427336B1Antenna array assembly
Publication Date: 2022.01.05 CAMBIUM NETWORKS
  • EP3427336B1 patent drawingFigure 1
  • EP3427336B1 patent drawingFigure 2
  • EP3427336B1 patent drawingFigure 3

AI summary

An antenna array assembly comprises at least a first and second antenna element, each comprising at least one radiator element (3a, 3b) in a substantially parallel relationship to a respective ground plate (2a, 2b), and an isolator bar (1b) disposed between the respective ground plates (2a, 2b) of the first and second antenna elements, the isolator bar (1b) being elongate having a cross- section comprising a T shape, the cross-section being across a long axis. The isolator bar (1b) comprises a support bar in contact with the ground plates forming the stem of the T shape, and a cross piece forming the top of the T shape. The cross piece of the isolator bar has a width in the cross-section of at least a quarter of a wavelength at an operating frequency of the antenna array, whereby to provide radio frequency isolation between the first and second antenna elements.