MIMO Antenna Non-Feed Element Grounding for Correlation Reduction

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Solution Overview

Problem

Current MIMO antenna systems face challenges in achieving low correlation and balanced antenna efficiency, particularly in the 700 MHz band, where high-frequency currents lead to difficulties in modifying antenna design for improved directionality and efficiency.

Innovation Solution

The proposed antenna apparatus incorporates a non-feed element grounded at specific points on the board, with varying inductance values and positions, to reduce correlation and enhance antenna efficiency, allowing for adjustable resonant frequencies and improved multiplexing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a non-feed element is coupled in the vicinity of a feed element to reduce correlation, then antenna correlation is improved, but antenna efficiency becomes unbalanced between antennas

Engineering Contradiction:
Improveantenna correlationVSAvoidantenna efficiency balance
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

A ground point is introduced as an intermediary element between the non-feed element and the circuit board. This ground point serves as a mediator that allows the non-feed element to influence correlation while maintaining symmetry and balance in antenna efficiency through proper grounding configuration

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies homogeneity by making both antennas have identical structures with non-feed elements coupled at symmetric positions relative to their respective feed elements. This ensures that both antennas have equal efficiency while achieving low correlation through the non-feed elements

Inventive Principle:
Principle #33Homogeneity

2Reliability

If antenna design is modified to change directionality in the 700 MHz band, then correlation may be improved, but the effect is minimal because high-frequency current flows throughout the terminal board

Engineering Contradiction:
Improveantenna correlationVSAvoiddesign effectiveness
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts the non-feed element from the traditional feed element design and couples it separately to the circuit board at a ground point. This separation allows the non-feed element to specifically control correlation without being constrained by the omnidirectional current distribution that limits conventional directionality modifications

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the operational parameters by introducing non-feed elements with specific electrical characteristics (inductance values of 3.3nH or 6.8nH) that resonate at target frequencies. This parameter change enables effective correlation control in the 700 MHz band where conventional geometric modifications are ineffective

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 solution effectively decreases correlation and improves antenna efficiency in the 700 MHz band, achieving better multiplexing efficiency and gain balance between antennas, thus addressing the limitations of existing MIMO systems.

Implementation Method 1

allowing for adjustable resonant frequencies and improved multiplexing efficiency

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

a non-feed element grounded at specific points on the board, with varying inductance values and positions

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Data Source

PatentEP2515379B1Antenna apparatus
Publication Date: 2019.06.19 SONY GROUP CORP
  • EP2515379B1 patent drawingFigure 1
  • EP2515379B1 patent drawingFigure 2A~2C
  • EP2515379B1 patent drawingFigure 3

AI summary

An antenna apparatus that includes a first antenna having a first feed point, a second antenna having a second feed point, and a first non-feed element grounded at a first ground point disposed at a first predetermined distance from the first feed point and the second feed point.