Body Area Network Coils Using Magnetic Human Body Coupling

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Solution Overview

Problem

Existing wearable devices face challenges in achieving low power consumption, cost-effectiveness, and efficient wireless communication due to anatomical size constraints and the limitations of conventional wireless communication methods, such as galvanic and capacitive human body communication systems, which suffer from high path loss and variability.

Innovation Solution

A body area network utilizing a combination of near and far magnetic fields, where a transmitter coil generates magnetic fields that leverage the human body's high permittivity to enhance far-field magnetic flux density, allowing for resonant coupling between coils to achieve lower path loss and improved communication reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional wireless communication methods (Bluetooth, WiFi, Zigbee) are used, then communication range and data rate are improved, but power consumption and path loss increase significantly

Engineering Contradiction:
Improvedata rateVSAvoidpower consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The patent introduces the human body as an intermediary communication channel. Instead of direct air-based wireless communication between devices, the system uses the human body's high permittivity tissue as a mediator to guide and concentrate electromagnetic energy, enabling low-power communication through body-coupled paths while maintaining acceptable data rates

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of energy

If galvanic coupling is used for body communication, then path loss is reduced, but security/privacy concerns and interference vulnerability arise

Engineering Contradiction:
Improvepath lossVSAvoidsecurity and interference resiliency
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent replaces the galvanic (electrical current-based) coupling mechanism with a magnetic field-based coupling mechanism. By using magnetic near-field communication through the body instead of direct electrical galvanic coupling, the system achieves similar low path loss while inherently improving security and interference resistance, as magnetic fields do not require direct electrical contact and are less susceptible to electromagnetic interference

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Loss of energy

If capacitive eHBC systems are used, then path loss is reduced compared to conventional radios, but environmental variability and ground plane requirements increase complexity

Engineering Contradiction:
Improvepath lossVSAvoidground plane requirements
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the requirement for large ground planes from the system. By using magnetic coupling through the body rather than capacitive coupling that requires extensive ground structures, the system achieves comparable or better path loss performance while dramatically reducing device complexity and eliminating environmental variability associated with ground plane configurations

Inventive Principle:
Principle #2Taking out (Extraction)

4Volume of moving object

If small battery-powered devices are used, then device size is reduced, but communication range and reliability deteriorate due to limited energy budget

Engineering Contradiction:
Improvedevice sizeVSAvoidcommunication reliability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent changes the fundamental communication parameter from air-based electromagnetic radiation to body-coupled magnetic field transmission. By operating in the magnetic near-field regime and utilizing the body's high permittivity, the system achieves extended effective communication range and improved reliability for small battery-powered devices, as the body-coupled path provides lower loss and more stable transmission characteristics

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 magnetic human body channel (mHBC) system achieves at least 20 dB lower path loss compared to far-field radios and eHBC systems, providing reliable and secure communication with reduced power consumption, while minimizing environmental and posture-related variability.

Implementation Method 1

A transmitter drives the first coil to generate the body leveraged magnetic field through the first coil

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 2

the transmitter is configured to drive the first coil at a frequency selected such that the body leveraged magnetic field simultaneously includes near-field and far-field components and the far-field components are enhanced by a high permittivity of bodily tissue

Methodology Applied
Scientific EffectDielectric Permittivity: Dielectric Permittivity

Implementation Method 3

allowing for resonant coupling between coils to achieve lower path loss and improved communication reliability

Methodology Applied
Scientific EffectMagnetic Resonance: Resonance

Implementation Method 4

A body area network that uses a near magnetic field and a far magnetic field simultaneously for communications

Methodology Applied
Scientific EffectMagnetic Field: Magnetic Field

Data Source

PatentEP3342042B1Low power magnetic field body area network
Publication Date: 2022.04.13 RGT UNIV OF CALIFORNIA
  • EP3342042B1 patent drawingFigure 1A
  • EP3342042B1 patent drawingFigure 1B
  • EP3342042B1 patent drawingFigure 2A~2B

AI summary

The invention provides a body area network that uses a near magnetic field for communications. A first coil is configured to be worn on a body portion of a human. A transmitter drives the first coil to generate a magnetic body field through the first magnetic coil. A second coil couples to the signal transmitted via the first coil matched to the magnetic field and first coil. A receiver for receiving the signal from the second coil. A method for establishing network communications using the human body as a magnetic field includes associating a transmitter coil with a portion of a human body, the transmitter coil being configured to couple to a receiver coil in a near field of the human body; driving the transmitter coil to generate a magnetic near field around the human body; and coupling to the magnetic near field with a receiver coil.