Cascaded Coil Antenna for Multi-Surface NFC Coverage

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Solution Overview

Problem

Conventional NFC antenna configurations in thin portable devices are limited in operational functionality, restricting information transfer to specific surfaces and directions, which hinders user convenience and efficiency in near field coupling applications like wireless power transfer and near field communications.

Innovation Solution

A cascaded coil antenna configuration is implemented, where two separate coil antennas are connected in series through a coaxial cable, allowing for independent placement on various surfaces and minimizing parasitic loops, with a ferrite flux guide to ensure same-phase current induction and magnetic field directionality for enhanced coupling capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional single coil antenna configuration is used, then the device structure remains simple, but the operational functionality is limited to specific surfaces and directions

Engineering Contradiction:

Improvemulti-surface coverageVSAvoidantenna configuration

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The antenna system is divided into multiple independent coil segments (first coil and second coil) that can be independently placed on different surfaces of the portable device. Each coil functions as a separate NFC antenna, enabling multi-surface coverage while maintaining the simplicity of individual coil structures.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The portable device is equipped with multiple coil antennas that can operate on different surfaces (front, back, sides), making the NFC functionality universal across multiple contact surfaces. This allows the device to establish NFC connections regardless of which surface is brought into proximity with another device.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If multiple separate coil antennas are used for multi-surface coverage, then operational flexibility improves, but parasitic loops and coupling interference increase

Engineering Contradiction:

Improvemulti-surface NFC capabilityVSAvoidparasitic loops

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

A coaxial cable is introduced as an intermediary connection element between the first and second coils. The coaxial cable's shielded structure acts as a mediator that transmits the signal while minimizing electromagnetic interference and preventing the formation of parasitic loops that would otherwise occur with unshielded connections.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs phase synchronization techniques where the coils are configured to operate in specific phase relationships. By controlling the phase of electromagnetic signals in each coil, the system maximizes constructive interference in desired directions while minimizing parasitic effects and unwanted coupling.

Inventive Principle:

Principle #36Phase transitions

3Volume of moving object

If thin portable devices use flat antennas, then the device maintains a compact form factor, but the antenna coverage area and coupling efficiency are reduced

Engineering Contradiction:

Improvedevice thicknessVSAvoidantenna effective area

Core Design Contradiction:

Volume of moving objectVSArea of stationary object

Solution Approach 1:

Instead of relying on a single large flat antenna that would increase device thickness, the patent distributes multiple compact coil antennas across different surfaces and dimensions of the thin device. This multi-dimensional arrangement effectively increases the total antenna coverage area while maintaining the device's thin profile.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 enables multi-surface near field coupling, improving the operational flexibility and efficiency of thin portable devices by allowing information transfer and power sharing across multiple surfaces while maintaining a compact form factor.

Implementation Method 1

guiding magnetic flux to induce a current in the same phase in both coil antennas

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

guiding magnetic flux to induce a current in the same phase in both coil antennas... generating magnetic fields in the same direction

Methodology Applied

Scientific EffectMagnetic field generation: Magnetic Field

Data Source

PatentEP2929617B1Cascaded coils for multi-surface coverage in near field communication

Publication Date: 2019.04.17 INTEL CORP

Figure 1(A)~1(B)
Figure 2
Figure 3(A)~3(B)

AI summary

Described herein are techniques related to near field coupling and wireless power transfers. A device may include a cascaded coil antenna to include a first coil antenna that is connected in series with a second coil antenna. The first and second coil antennas are independent antennas prior to cascading and are located in different surfaces of the device to establish near field coupling through front side, top side, bottom side, or corner side of the portable device. Furthermore, a flux guide may be placed in the cascaded coil antenna to facilitate magnetic flux at the first coil antenna and the second coil antenna to induce current of the same phase during receive mode. During transmit mode, the flux guide facilitates the magnetic flux at the first coil antenna and the second coil antenna to generate magnetic fields of the same direction.