Optical Fiber Electric Field Sensor Using Thermal Absorption

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Solution Overview

Problem

Conventional antennas for measuring electric field strength are physically large and can distort the field, making them unsuitable for confined spaces or precise location measurements, and they require metallic components that can interfere with the signal.

Innovation Solution

A device comprising an absorber material and a thermal insulator, with optically interrogable temperature sensors to measure temperature differences, allowing for accurate electric field strength measurement without perturbing the field, and using optical fibers to eliminate the need for metallic wires.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If antennas are made smaller to enable measurements in confined spaces, then the device size is reduced, but the signal picked up by the antenna cables and circuits becomes larger than the signal picked up by the antenna, reducing measurement sensitivity

Engineering Contradiction:

Improvedevice sizeVSAvoidsignal detection sensitivity

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent replaces the traditional antenna-based electromagnetic signal detection system with a thermal detection system. The absorber material converts electromagnetic energy to thermal energy, and temperature sensors detect the resulting temperature changes. This substitution eliminates the need for metallic antenna components and their associated cables, allowing for smaller device size without compromising sensitivity to weak electromagnetic signals.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an absorber material as an intermediary between the electromagnetic field and the temperature sensors. The absorber material absorbs electromagnetic energy and converts it to heat, which then serves as the detectable signal for the temperature sensors. This intermediary approach allows for effective signal detection without requiring direct electromagnetic coupling through metallic components.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If antennas use metallic components to maintain sensitivity, then measurement sensitivity is preserved, but the presence of the antenna itself distorts the electric field, making measurements unrepresentative

Engineering Contradiction:

Improvesignal detection sensitivityVSAvoidfield distortion

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent replaces metallic antenna components with non-metallic materials including the absorber material and thermal insulator. This substitution eliminates the harmful effect of metallic components distorting the electric field, as the non-metallic materials do not interact with the electromagnetic field in the same way. The field distortion is thereby eliminated while sensitivity is maintained through thermal detection of absorbed energy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If antennas are made larger to maintain electromagnetic cross section, then sensitivity to small signals is maintained, but the device size increases, preventing measurements in confined spaces

Engineering Contradiction:

Improvesignal detection sensitivityVSAvoidantenna size

Core Design Contradiction:

Measurement precisionVSLength of stationary object

Solution Approach 1:

The patent replaces the antenna-based electromagnetic detection system with a thermal detection system using absorber material and temperature sensors. This fundamental substitution allows for compact device design because the thermal detection mechanism does not require large electromagnetic cross sections. The sensitivity to small signals is maintained through the thermal conversion process, enabling both small size and high sensitivity simultaneously.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Enables precise and sensitive measurement of electric field strength with minimal distortion, allowing for smaller device size and improved sensitivity, capable of measuring fields in confined spaces and at precise locations.

Implementation Method 1

an absorber to absorb radiation at the frequency of the oscillating electric field

Methodology Applied

Scientific EffectElectromagnetic radiation absorption: Absorption (EM radiation)

Implementation Method 2

a thermal insulator transparent to radiation at the frequency of the oscillating electric field, which thermal insulator is arranged to thermally insulate the absorber

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 3

a first temperature sensor arranged to measure the temperature of the absorber, and a second temperature sensor arranged to measure the temperature external to the thermal insulator

Methodology Applied

Scientific EffectOptical interrogation of temperature: Photoluminescence

Data Source

PatentUS11782081B2Electric field sensor

Publication Date: 2023.10.10 MBDA UK

AI summary

There is disclosed a device for determining a strength of an oscillating electric field. The device comprises an absorber to absorb radiation at the frequency of the oscillating electric field, and a thermal insulator transparent to radiation at the frequency of the oscillating electric field, which thermal insulator is arranged to thermally insulate the absorber. The device also comprises a first temperature sensor arranged to measure the temperature of the absorber, and a second temperature sensor arranged to measure the temperature external to the thermal insulator. Methods of measuring electric field using such a device, and methods of calibrating such a device, are also disclosed.