Wireless Shape Measurement via Magnetic Induction Resonance

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Solution Overview

Problem

Conventional methods for measuring the shape of an object using sensors are hindered by the need for wires, which reduce mobility and comfort, especially in patient monitoring applications.

Innovation Solution

A magnetic induction radio sensor system utilizing a magnetic loop antenna and an antenna matching circuit with adjustable capacitance to form a resonant circuit with a fixed frequency, allowing wireless measurement of object shape without the need for wires.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wires are used to connect the sensor and external device, then measurement data transmission is achieved, but mobility and comfort are reduced

Engineering Contradiction:
Improvemeasurement data transmissionVSAvoidmobility and comfort
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent replaces the mechanical wire connection system with a wireless magnetic induction coupling system. The sensor uses a magnetic loop antenna that couples magnetically to an external device, eliminating the need for physical wires while maintaining data transmission capability. This substitution of mechanical connection with magnetic field coupling directly resolves the contradiction between reliable data transmission and mobility/comfort.

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

2Ease of operation

If a magnetic loop antenna is used to enclose the object, then wireless measurement is achieved, but the inductance varies with object shape making frequency unstable

Engineering Contradiction:
Improvewireless measurement capabilityVSAvoidresonant frequency stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent employs an adjustable capacitance module that dynamically changes the capacitance parameter in response to inductance variations caused by object shape changes. This parameter adjustment maintains the resonant frequency stability despite variations in the magnetic loop antenna's inductance, resolving the contradiction between wireless measurement capability and frequency stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system incorporates a feedback mechanism where the adjustable capacitance module continuously monitors and responds to inductance changes in the magnetic loop antenna. By detecting shape-induced inductance variations and compensating with corresponding capacitance adjustments, the system maintains stable resonant frequency operation while enabling wireless measurement.

Inventive Principle:
Principle #23Feedback

3Stability of the object's composition

If adjustable capacitance is added to maintain fixed resonant frequency, then frequency stability is improved, but device complexity increases

Engineering Contradiction:
Improveresonant frequency stabilityVSAvoidantenna matching circuit complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent uses an adjustable capacitance module that provides frequency stabilization through parameter change rather than complex circuitry. By varying the capacitance value in response to inductance changes, the system maintains fixed resonant frequency with relatively simple circuit implementation, avoiding the need for complex active frequency control systems.

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

Improves both mobility and comfort by enabling wireless, power-efficient, and secure shape measurement with reduced interference and regulatory compliance, suitable for medical applications.

Implementation Method 1

A magnetic induction radio sensor for measuring the shape of an object includes a magnetic loop antenna, where the inductance of the magnetic loop antenna depends on the shape of the object

Methodology Applied
Scientific EffectMagnetic induction: Electromagnetic Induction

Implementation Method 2

the antenna matching circuit includes an adjustable capacitance module configured to provide a particular capacitance such that the magnetic loop antenna and the antenna matching circuit form a resonant circuit and the resonant circuit has a fixed resonant frequency

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP2336713B1System for measuring the shape of an object using a magnetic induction radio sensor
Publication Date: 2016.03.30 NXP BV
  • EP2336713B1 patent drawingFigure 1~2
  • EP2336713B1 patent drawingFigure 3~4
  • EP2336713B1 patent drawingFigure 5~7

AI summary

A system and method for measuring the shape of an object using a magnetic induction radio sensor involves at least partially enclosing the object with a magnetic loop antenna of the magnetic induction radio sensor, where the inductance of the magnetic loop antenna depends on the shape of the object, and providing a particular capacitance at an antenna matching circuit coupled to the magnetic loop antenna in response to the inductance of the magnetic loop antenna such that the magnetic loop antenna and the antenna matching circuit form a resonant circuit and the resonant circuit has a fixed resonant frequency, where the particular capacitance is used to measure the shape of the object.