Dual-Polarized Microstrip Patch Antenna Array for Reduced Cross-Polarization

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Solution Overview

Problem

Existing dual-polarized antennas for portable radio devices face challenges with cross-polarization levels due to increasing device miniaturization, leading to bandwidth constraints and signal interference in bandwidth-constrained radio communication systems.

Innovation Solution

A compact dual-polarized antenna design featuring an array of corner-positioned square patches and connector strips on a substrate, with a single feed connection through a cross strip, ensuring symmetrical excitation and reduced cross-polarization levels, allowing for efficient dual-polarization operation within the IMS frequency band.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If device miniaturization is implemented to reduce antenna size, then antenna dimensions are reduced, but cross-polarization levels increase

Engineering Contradiction:
Improveantenna sizeVSAvoidcross-polarization levels
Core Design Contradiction:
Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent employs asymmetric positioning of feed connections relative to the patch antenna elements. The feed connections are positioned at specific asymmetric locations that create deliberate imbalance to cancel out harmful cross-polarization components generated by miniaturization, while maintaining compact overall dimensions.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent modifies geometric parameters of the antenna structure, including patch dimensions, feed connection positions, and spacing relationships. By optimizing these parameters, the antenna achieves reduced size while controlling cross-polarization levels through parameter tuning rather than relying on symmetric configurations.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If dual-polarization techniques are used to double communication capacity, then bandwidth utilization is improved, but device complexity increases

Engineering Contradiction:
Improvecommunication capacityVSAvoidantenna system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent combines dual-polarization functionality into a single integrated patch antenna structure rather than using separate antennas for each polarization. The asymmetric feed configuration enables both polarization modes to be excited from one compact structure, achieving doubled communication capacity without proportional increase in device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single patch antenna structure serves multiple functions by supporting both polarization modes simultaneously. The asymmetric feed system enables the same physical structure to handle multiple communication channels and polarization states, reducing the need for separate dedicated components for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Volume of moving object

If compact antenna design is implemented for portable devices, then antenna dimensions are reduced, but signal interference increases

Engineering Contradiction:
Improveantenna dimensionsVSAvoidsignal interference
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent applies different structural characteristics to different regions of the antenna. The asymmetric feed connections are positioned at specific local locations on the patch structure, creating localized field distributions that minimize interference while maintaining overall compactness. Different portions of the antenna have optimized local geometries to reduce harmful interactions.

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 design achieves high-gain, high-efficiency dual-polarization operation with reduced cross-polarization, enhancing communication capacity and signal quality in portable radio devices operating at the IMS frequency band.

Implementation Method 1

transducing signal energy pursuant to a dual-polarization scheme

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 2

symmetrical excitation at a resonant frequency

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP1983613B1Dual-polarized, microstrip patch antenna array, and associated methodology, for radio device
Publication Date: 2009.11.18 BLACKBERRY LTD
  • EP1983613B1 patent drawingFigure 1
  • EP1983613B1 patent drawingFigure 2
  • EP1983613B1 patent drawingFigure 3

AI summary

A dual-polarized antenna, and an associated methodology, is provided for a radio device, such as a mobile station. The antenna is formed of a plurality of patches configured into an array, symmetrical in both a first polarization direction and a second polarization direction. Adjacent patches of the array arc interconnected by connecting strips that are also symmetrically positioned in the two directions. These connecting strips not only act as feeding lines for the patches but also operate as in-phase radiation elements in each polarization direction. A transverse strip extends between a pair of transversely positioned patches. And a single feed connection is provided thereat.