Body Area Network Coils Using Magnetic Body Fields for Low Path Loss

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Solution Overview

Problem

Existing body area network communication systems face challenges with high power consumption and path loss due to anatomical constraints and the poor conductivity of human tissues, limiting the effectiveness of both galvanic and capacitive human body communication methods.

Innovation Solution

A magnetic human body channel (mHBC) system that utilizes magnetic fields to transmit data through coils positioned on the body, leveraging the high dielectric constant of biological tissues to enhance far-field properties and achieve lower path loss compared to conventional methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If galvanic coupling or capacitive eHBC is used to reduce path loss, then communication efficiency improves, but power consumption increases due to the poor conductivity of human tissues

Engineering Contradiction:

Improvepath lossVSAvoidpower consumption

Core Design Contradiction:

Loss of energyVSUse of energy by moving object

Solution Approach 1:

The patent replaces electrical field-based communication (galvanic/capacitive coupling) with magnetic field-based communication. By using magnetic fields instead of electrical fields, the system avoids the high power consumption associated with overcoming the poor conductivity of human tissues, while still achieving low path loss through the body's natural magnetic properties.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental parameter of the communication field from electrical to magnetic. This parameter change allows the system to exploit different physical properties of human tissues - specifically, the magnetic permeability of tissues - to achieve efficient communication without the power consumption penalties of electrical field methods.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If conventional transceivers are used to improve wireless communication performance, then communication reliability improves, but device cost and complexity increase

Engineering Contradiction:

Improvecommunication reliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex conventional transceiver circuits with a simpler magnetic field-based communication system. By using magnetic coupling between coils instead of traditional radio frequency transceivers, the system achieves reliable communication with significantly reduced circuit complexity and lower device cost.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Duration of action of moving object

If battery size is increased to extend operational lifetime, then duration of action improves, but anatomical constraints are violated

Engineering Contradiction:

Improveoperational lifetimeVSAvoidbattery volume

Core Design Contradiction:

Duration of action of moving objectVSVolume of moving object

Solution Approach 1:

The patent converts the harmful effect of poor tissue conductivity (which normally increases power consumption) into a beneficial magnetic field propagation medium. By using magnetic fields, the system achieves efficient power transfer through the body without requiring large batteries, thus extending operational lifetime while respecting anatomical constraints.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 mHBC system achieves significantly lower path loss than both far-field radios and eHBC systems, enabling reliable and energy-efficient communication over short distances while maintaining security and privacy benefits, with path loss reduced by at least 20 dB across the human body.

Implementation Method 1

A transmitter drives the first coil to generate a magnetic body field through the first magnetic coil at a frequency selected such that the body leveraged magnetic field simultaneously includes near-field and far-field components

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

A second coil couples to the signal transmitted via the first coil, and the second coil is configured and positioned to receive both of the near- and far-field components

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS10623112B2Low power magnetic field body area network

Publication Date: 2020.04.14 RGT UNIV OF CALIFORNIA

AI summary

The invention provides a body area network. A first coil is configured to be worn on a body portion of a human, and the first coil is configured and positioned to use a body leveraged magnetic field. A transmitter drives the first coil to generate a magnetic body field through the first magnetic 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 dielectric constant of bodily tissue. A second coil couples to the signal transmitted via the first coil, and the second coil is configured and positioned to receive both of the near- and far-field components. A receiver receives the signal from the second coil. A method for establishing network communications using the human body as a magnetic field drives a transmitter coil to generate magnetic near- and far-field components that include the human body as a medium to propagate the magnetic near- and far-field components, wherein the driving is at a frequency and transmission power selected to enhance far-field magnetic flux density via guiding at a boundary of the human body.