Foldable Slot Antenna Layout for Balanced Signal Coverage

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Solution Overview

Problem

The design of antennas in foldable electronic devices with a full metal industry design is challenging due to limited internal space, leading to poor antenna directivity and signal coverage, especially when the device is unfolded, with energy being centralized in front of the screen and signal weak behind it.

Innovation Solution

A foldable electronic device with a slot antenna design featuring perpendicular branches, where one branch is distributed along the folding position and the other is either along the side edge or far away from it, balancing horizontal and vertical currents to reduce directivity and improve signal coverage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a full metal industry design is used with large ground plates, then the device achieves a thin profile and robust structure, but the antenna directivity coefficient increases and signal coverage capability deteriorates

Engineering Contradiction:
Improvestructural robustnessVSAvoidsignal coverage capability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The slot antenna is divided into two perpendicular branches (first branch along the folding position, second branch along the side edge) to create multiple current paths. This segmentation allows the antenna to excite both horizontal and vertical currents independently, achieving omnidirectional radiation patterns and improving signal coverage capability while maintaining the full metal design structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The antenna design transitions from a conventional single-directional slot to a two-dimensional perpendicular branch structure. By adding the vertical dimension through the second branch perpendicular to the first branch, the antenna achieves three-dimensional current distribution, reducing directivity coefficient and enabling omnidirectional signal coverage.

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

2Volume of moving object

If the antenna is positioned in the limited internal space, then the device maintains its thin profile, but the antenna directivity coefficient increases and radiation pattern becomes unbalanced

Engineering Contradiction:
Improvedevice thicknessVSAvoidantenna radiation pattern balance
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The antenna utilizes the perpendicular dimension by creating two branches at right angles to each other. The first branch extends along the folding position while the second branch extends along the side edge, creating a two-dimensional current distribution that achieves balanced omnidirectional radiation without increasing device thickness.

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

3Ease of manufacture

If conventional slot antenna designs are used, then the manufacturing process is simple, but the antenna directivity coefficient is high and signal coverage is poor

Engineering Contradiction:
Improveantenna fabrication simplicityVSAvoidsignal coverage capability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The slot antenna is segmented into two perpendicular branches that can be independently optimized. The first branch is configured along the folding position and the second branch along the side edge, with each branch contributing to different current components. This segmentation maintains manufacturing simplicity while achieving the complex function of omnidirectional radiation through the perpendicular geometry.

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

The antenna design effectively reduces the directivity coefficient and enhances omnidirectional signal coverage by balancing current distribution, ensuring balanced radiation patterns both in front and behind the display.

Implementation Method 1

the first branch and the second branch are perpendicular to each other, a horizontal current and a vertical current that are on the housing ground plate may be excited, and the horizontal current and the vertical current jointly generate radiation

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Data Source

PatentEP4459790B1Folding electronic device comprising antenna
Publication Date: 2026.02.25 HONOR DEVICE CO LTD
  • EP4459790B1 patent drawingFigure 1A~1B
  • EP4459790B1 patent drawingFigure 2A~2B
  • EP4459790B1 patent drawingFigure 2C~3A

AI summary

Embodiments of this application provide a foldable electronic device including an antenna. The foldable electronic device may include a first body, a second body, and a rotating shaft connected to the first body and the second body. The first body and the second body are rotatable around the rotating shaft. As the first body and the second body rotate, a form of the foldable electronic device may be switched between a folded state and an unfolded state. The antenna may be a slot antenna formed by hollowing out a metal housing of the first body or a metal housing of the second body. The slot antenna may include a first branch and a second branch, where the first branch and the second branch may be perpendicular to each other. In this way, because the first branch and the second branch are perpendicular to each other, a horizontal current and a vertical current that are on a housing ground plate may be excited, and the horizontal current and the vertical current jointly generate radiation. This can effectively reduce the antenna directivity coefficient, improve an antenna radiation pattern, and improve a signal coverage capability of the electronic device.