Flexible Antenna Embedded in PCB for Thinner Handheld Devices

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Solution Overview

Problem

There is a challenge in designing portable electronic devices (PEDs) that are both compact and performant, as reducing size and weight while maintaining performance is complicated by the need for thinner stack-ups which can negatively affect mechanical dimensions and involve complex assembly processes.

Innovation Solution

The solution involves a flexible antenna assembly with split copper layers and integrated circuit boards, where the antenna layers are embedded within the PCB, allowing for a thinner form factor while maintaining performance by using a combination of flexible dielectric and conductive layers with ferrite for inductive shielding, and a pressure-sensitive adhesive for secure mounting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If the PED stack-up is made thinner to reduce overall thickness, then the mechanical dimensions and portability are improved, but the assembly process becomes more complicated and performance may deteriorate

Engineering Contradiction:
ImprovePED thicknessVSAvoidassembly process complexity
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The patent combines the antenna assembly with the circuit board by embedding the antenna within the PCB structure. The antenna conductive traces are integrated directly into the circuit board layers, eliminating the need for separate antenna components and complex assembly processes. This merging allows for a thinner overall stack-up while maintaining antenna performance and simplifying manufacturing.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The antenna structure is nested within the multi-layer circuit board stack-up. The antenna conductors are embedded between internal PCB layers, with the antenna assembly contained within the circuit board thickness itself. This nesting approach reduces the overall PED thickness while maintaining antenna functionality without requiring additional external space.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Length of stationary object

If the PED stack-up is made thinner to reduce overall thickness, then the mechanical dimensions and portability are improved, but the antenna performance and signal quality may worsen

Engineering Contradiction:
ImprovePED thicknessVSAvoidantenna performance
Core Design Contradiction:
Length of stationary objectVSReliability

Solution Approach 1:

The patent applies different material properties and structural characteristics to different regions of the antenna assembly. Ferrite materials are strategically placed in specific areas to enhance magnetic field confinement and improve antenna performance. The circuit board uses varying copper trace widths, layer configurations, and dielectric materials in different zones to optimize signal quality while maintaining a thin overall profile.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The antenna assembly utilizes composite construction combining ferrite magnetic shielding materials with the circuit board's dielectric and conductive layers. This composite structure enhances antenna performance by improving signal confinement and reducing interference, allowing for reduced thickness without compromising reliability. The multi-material approach enables better electromagnetic performance in a thinner form factor.

Inventive Principle:
Principle #40Composite materials

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 approach reduces the overall thickness of the PED by approximately 0.42 mm, making it easier to carry and use while maintaining desired performance characteristics, and allows for normal processing techniques to be used, simplifying manufacturing and maintaining control over copper thickness for the antenna coils.

Implementation Method 1

at least part of the flex-antenna assembly includes ferrite for providing inductive shielding to the flex-antenna assembly

Methodology Applied
Scientific EffectInductive shielding: Magnetic Field

Implementation Method 2

a pressure-sensitive adhesive for secure mounting

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentEP2876868B1Handheld device and method of manufacture thereof
Publication Date: 2019.01.30 BLACKBERRY LTD
  • EP2876868B1 patent drawingFigure 1A~2
  • EP2876868B1 patent drawingFigure 3A~3B
  • EP2876868B1 patent drawingFigure 4A

AI summary

A handheld device comprises a casing acting as a protective supporting framework of the handheld device. A circuit board mechanically supports and electrically connects with each other electronic components of the handheld device and is configured to be embedded into the casing. At least one wireless communications circuit transmits signals and data from the handheld device and is carried by the circuit board. A flex-antenna assembly is electrically coupled to the wireless communications circuit for sending and receiving the signals and data, defines flexible dielectric and conductive layers of the flex-antenna assembly disposed adjacent to each other, and is embedded into the circuit board.