Antenna Module Metal Frame Grounding for Cross-Talk Reduction

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Solution Overview

Problem

In mobile terminals, the close proximity of LTE MIMO diversity antennas and WiFi antennas leads to significant coupling, affecting receiving performance due to resonance frequency interference and cross-talk.

Innovation Solution

The second section of the metal frame is electrically connected to the ground point of the mobile terminal via a contact point, forming loops that tune the resonance frequency of the second antenna, reducing cross-talk and ensuring isolation between the first and second antennas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple antennas are integrated in the same mobile terminal to enable reception of different wireless signals, then the functionality and signal reception capability are improved, but serious coupling occurs between the antennas due to short distance, deteriorating receiving performance

Engineering Contradiction:
Improvesignal reception capabilityVSAvoidcoupling between antennas
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a metal frame as an intermediary structure between the first and second antennas. The metal frame includes a first section and a second section that are spatially separated and electrically connected through a grounding connection, acting as a mediator to manage electromagnetic interactions between the antennas without requiring direct physical separation of the antenna elements themselves.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent utilizes the three-dimensional space within the mobile terminal by positioning the first and second sections of the metal frame at different spatial locations and orientations. The first section is arranged in a first direction while the second section is arranged in a second direction different from the first, effectively using spatial dimensionality to reduce coupling while maintaining compact integration.

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

2Volume of moving object

If the distance between the first antenna and second antenna is reduced to achieve compact design, then the device size is reduced, but serious coupling and cross-talk occur between the antennas, affecting receiving performance

Engineering Contradiction:
Improvedevice sizeVSAvoidcross-talk between antennas
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent arranges the first and second sections of the metal frame in different spatial directions (first direction and second direction respectively), utilizing three-dimensional spatial arrangement to maintain adequate electromagnetic isolation between antennas while minimizing the overall device volume. This directional separation in multiple dimensions allows compact integration without sacrificing performance.

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

Solution Approach 2:

The patent applies different local configurations to different parts of the metal frame structure. The first section has specific geometric characteristics optimized for its location, while the second section has different geometric characteristics suited to its position. This localized optimization allows each section to effectively manage electromagnetic fields in its specific region, reducing overall coupling.

Inventive Principle:
Principle #3Local quality

3Device complexity

If the metal frame sections are arranged in the same direction to simplify structure, then the manufacturing complexity is reduced, but resonance frequency interference and cross-talk between antennas increase

Engineering Contradiction:
Improvestructural complexityVSAvoidresonance frequency interference
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces asymmetry in the arrangement of the metal frame sections by positioning the first section in a first direction and the second section in a second direction different from the first. This asymmetric configuration breaks the symmetry that would otherwise create resonant modes and cross-talk, while adding only minimal complexity to the overall structure.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent divides the metal frame into distinct first and second sections that are electrically connected but spatially separated. This segmentation allows each section to be independently optimized for its specific function and location, reducing unwanted electromagnetic interactions while maintaining the overall structural integrity through the electrical connection.

Inventive Principle:
Principle #1Segmentation

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 effectively reduces cross-talk between antennas, enhancing isolation and allowing both antennas to radiate more energy efficiently by tuning the resonance frequency and minimizing interference.

Implementation Method 1

The second section of the metal frame is electrically connected to the ground point of the mobile terminal via a contact point, forming loops that tune the resonance frequency of the second antenna

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

a first feed point of the first antenna is electrically connected to the first section of the metal frame via a second connection point, and the first feed point, the first section of the metal frame, and the first ground point form a first loop

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3057176B1Antenna module and mobile terminal
Publication Date: 2021.07.21 XIAOMI INC
  • EP3057176B1 patent drawingFigure 1~2
  • EP3057176B1 patent drawingFigure 3~4A
  • EP3057176B1 patent drawingFigure 4B~4C

AI summary

The present invention provides an antenna module and a mobile terminal for improving antenna performance of the mobile terminal (10). The antenna module includes: a first antenna (11) and a second antenna (21); a first ground point (12) of the first antenna (11) is electrically connected to a first section (17) of a metal frame of the mobile terminal (10) via a first connection point (14), a first feed point (13) of the first antenna (11) is electrically connected to the first section (17) of the metal frame via a second connection point (15); and the second antenna (21) is electrically connected to a second section (27) of the metal frame of the mobile terminal (10) via a third connection point (24), the second section (27) of the metal frame is electrically connected to a ground point of the mobile terminal (10) via a first contact point (31).