Dual-Mode Feed Network for Antenna Array Isolation

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Solution Overview

Problem

Existing multi-band antenna arrays face challenges in isolating different antenna elements due to the proximity of their feed lines, leading to complex and costly three-dimensional structures with limited applicability.

Innovation Solution

A dual-mode feed network using a combination of waveguide and multi-conductor transmission line structures, implemented on a multilayer PCB, which employs different electromagnetic propagation modes to isolate and efficiently feed antenna elements, allowing for compact and cost-effective designs suitable for wireless communication devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If different antenna elements are placed in close proximity to form multi-band antenna arrays, then the antenna array size is reduced, but isolation between antenna elements becomes difficult to achieve

Engineering Contradiction:
Improveantenna array sizeVSAvoidisolation between antenna elements
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The invention divides the feed network into separate feed lines for different antenna elements, with each feed line dedicated to specific frequency bands. This segmentation allows compact arrangement of antenna elements while maintaining isolation through separate feeding paths, resolving the contradiction between reduced array size and maintained element isolation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces a ground structure as an intermediary between feed lines of different antenna elements. This ground structure acts as a shielding barrier that provides isolation between elements operating in different frequency bands, enabling close proximity placement while maintaining required isolation levels.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If feed lines for different antenna elements are placed in close proximity, then the antenna array structure is simplified, but performance deteriorates due to lack of isolation

Engineering Contradiction:
Improvefeed network structureVSAvoidantenna element isolation
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The feed network is segmented into distinct feed lines, each dedicated to specific antenna elements and frequency bands. This segmentation simplifies the overall structure by eliminating complex three-dimensional routing while maintaining isolation through the dedicated nature of each feed line path.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention applies different structural characteristics to different regions of the feed network. Ground structures are strategically placed in specific locations where isolation is needed, while other regions maintain simplified feed line configurations. This localized approach maintains performance without requiring complex structures throughout the entire system.

Inventive Principle:
Principle #3Local quality

3Reliability

If complex three-dimensional feed network structures are used to isolate antenna elements, then isolation performance is improved, but manufacturing cost increases and applicability is limited

Engineering Contradiction:
Improveantenna element isolationVSAvoidmanufacturing cost and applicability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention transitions from complex three-dimensional feed network structures to a planar two-dimensional configuration implemented on PCB substrates. By utilizing the ground plane dimension and strategic placement of ground structures within the planar layout, the design achieves effective isolation while maintaining manufacturing simplicity and broad applicability through standard PCB fabrication processes.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The invention changes the structural parameters of the feed network by using planar geometries and standard PCB materials instead of complex three-dimensional structures. This parameter change maintains isolation performance through optimized ground structure placement and feed line design while dramatically improving ease of manufacture and applicability to various frequency bands and antenna configurations.

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 dual-mode feed network effectively isolates antenna elements, facilitates impedance matching, and reduces the volume occupied by the feed network, enabling narrower port spacing and improved performance in multi-band antenna arrays, particularly for mmW applications.

Implementation Method 1

a first signal transmission structure, such as a waveguide structure, configured for propagating signals according to a first electromagnetic propagation mode, such as a waveguide mode

Methodology Applied
Scientific EffectWaveguide mode propagation: Waveguide

Implementation Method 2

a second signal transmission structure, such as a multi-conductor transmission line structure, configured for propagating signals according to a second electromagnetic propagation mode, such as a transmission line mode

Methodology Applied
Scientific EffectTransmission line mode propagation: Conduction (electrical)

Data Source

PatentEP3248246B1Multi-mode feed network for antenna array
Publication Date: 2021.08.25 HUAWEI TECH CO LTD
  • EP3248246B1 patent drawingFigure 1
  • EP3248246B1 patent drawingFigure 2
  • EP3248246B1 patent drawingFigure 3

AI summary

A dual-mode feed network for an antenna array or combination antenna is provided. Two transmission line structures propagate signals according to two different electromagnetic propagation modes, such as TE, TM, TEM and quasi TEM modes. The two transmission line structures are operatively coupled to different components of the antenna array. One transmission line structure may be a stripline or microstrip, and the other transmission line structure may be a waveguide such as a Substrate Integrated Waveguide. Both transmission line structures may branch to reach multiple elements of the antenna array. The transmission lines may share common features, for example by embedding the stripline within the waveguide.