Antenna Module Decoupling Structure for Compact MIMO Isolation

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Solution Overview

Problem

In MIMO systems, the close placement of antennas due to space constraints leads to strong signal coupling, resulting in poor port isolation and radiation efficiency.

Innovation Solution

The use of a decoupling structure with a specific resonance frequency and dimensions, positioned between antennas, to reduce coupling and improve isolation while maintaining radiation efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the distance between antennas is increased to improve port isolation, then the isolation between antennas is improved, but the device size increases and space availability is reduced

Engineering Contradiction:

Improveport isolationVSAvoiddevice size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

A decoupling structure is introduced as an intermediary element positioned between the first and second antennas. This decoupling structure reduces the coupling between antennas through electromagnetic interaction, achieving improved port isolation without requiring increased antenna separation distance. The decoupling structure acts as a mediator that manages the electromagnetic fields between closely-spaced antennas.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The decoupling structure's dimensions are specifically designed with its cross-sectional height between 0.04λ and 0.16λ, and distances to antenna phase centers between 0.1λ and 0.45λ. By optimizing these dimensional parameters, the decoupling structure achieves effective decoupling while maintaining a compact form factor that does not significantly increase device size.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If additional decoupling structures are added to reduce signal coupling, then port isolation is improved, but radiation performance is degraded

Engineering Contradiction:

Improveport isolationVSAvoidradiation efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The decoupling structure's cross-sectional height is carefully controlled within 0.04λ to 0.16λ, which is sufficient to achieve decoupling effect while minimizing interference with the antennas' radiation patterns. The distances from the decoupling structure to each antenna's phase center are optimized between 0.1λ and 0.45λ, ensuring effective coupling reduction without significantly impacting radiation efficiency.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The decoupling structure is designed with minimal necessary dimensions to achieve the required decoupling effect. Rather than using an oversized structure that would definitely impact radiation, the design applies just enough decoupling action (cross-sectional height of 0.04λ-0.16λ) to achieve port isolation while minimizing negative effects on radiation performance.

Inventive Principle:

Principle #16Partial or excessive action

3Volume of moving object

If antennas are placed close together to reduce device size, then device compactness is improved, but signal coupling between antennas increases

Engineering Contradiction:

Improvedevice sizeVSAvoidsignal coupling

Core Design Contradiction:

Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The decoupling structure serves as an intermediary element that manages the electromagnetic interaction between closely-spaced antennas. By positioning this structure between the antennas at specific distances (0.1λ to 0.45λ from each antenna's phase center), it effectively reduces the harmful coupling effects while allowing the antennas to remain in a compact arrangement.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The decoupling structure utilizes the strong electromagnetic coupling that naturally occurs between closely-spaced antennas and converts this harmful effect into a beneficial one. By resonating at the operating frequency, the decoupling structure creates counteracting electromagnetic fields that cancel out the harmful coupling, transforming the problem of strong interaction into a solution for port isolation.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 proposed solution effectively improves port isolation and maintains radiation efficiency, even in limited spaces, by strategically placing the decoupling structure between antennas.

Implementation Method 1

a resonance frequency of the first decoupling structure is the first frequency

Methodology Applied

Scientific EffectResonance: Resonance

Data Source

PatentUS20250079697A1Antenna module and communication device

Publication Date: 2025.03.06 HUAWEI TECH CO LTD

AI summary

This disclosure provides an antenna module and a communication device. The antenna module includes a ground plane, a first antenna, a second antenna, and a first decoupling structure. A cross-sectional height of the first decoupling structure, a distance between the first decoupling structure and the first antenna, and a distance between the first decoupling structure and the second antenna are set to reduce an amount of coupling between the first antenna and the second antenna. This facilitates a miniaturized design of the antenna module, and improves isolation on a premise thereby ensuring antenna efficiency.