Terahertz Pixel Sensor With Phase-Aligned Synchronous Filtering

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Solution Overview

Problem

Current terahertz image sensors face challenges in producing low-cost, integrated terahertz image matrix sensors due to difficulties in implementing synchronous demodulation methods, particularly in achieving phase alignment between control and measured signals, which affects signal amplification and spatial resolution.

Innovation Solution

A terahertz image sensor design incorporating a matrix of pixels with an antenna for receiving modulated terahertz radiation and a synchronous filter with N paths, each comprising capacitive and resistive elements, along with switch-controlled circuits, to filter and amplify signals independently of phase differences, using a modulation frequency between 10 kHz and 1 MHz.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If synchronous demodulation methods are implemented in terahertz image sensors, then signal amplification and spatial resolution are improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvespatial resolutionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The sensor is divided into a matrix of independent pixels, each with its own antenna and synchronous filter. This segmentation allows each pixel to process signals independently, achieving high spatial resolution while using standardized, low-complexity building blocks that can be manufactured using standard CMOS processes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements synchronous demodulation using periodic switching at the modulation frequency. Each pixel's synchronous filter switches periodically to demodulate the modulated terahertz signal, enabling signal amplification and noise extraction without requiring complex continuous processing circuits.

Inventive Principle:
Principle #19Periodic action

2Measurement precision

If phase alignment between control and measured signals is achieved, then signal processing accuracy is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvesignal processing accuracyVSAvoidphase alignment precision
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

Each pixel generates its own control signal locally, which is used to drive the synchronous switching of its own filter. This self-service approach ensures automatic phase alignment between the control signal and the measured signal, eliminating the need for complex external phase synchronization circuits and reducing manufacturing precision requirements.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The synchronous filter circuit is designed to be universal across all pixels in the matrix. Each pixel uses the same standardized circuit design that inherently produces phase-aligned control and measured signals, allowing mass production using standard CMOS processes without requiring pixel-specific phase calibration.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of manufacture

If low-cost integrated production is implemented, then manufacturing cost is reduced, but signal processing performance may deteriorate

Engineering Contradiction:
Improvemanufacturing costVSAvoidsignal processing performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces complex mechanical or external synchronization systems with integrated CMOS electronic circuits. Each pixel's synchronous filter is fully integrated using standard semiconductor manufacturing processes, eliminating the need for expensive external components while maintaining high signal processing performance through on-chip phase-aligned demodulation.

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

This design enables efficient signal processing and amplification, effectively extracting useful signals from noise while maintaining low-cost and integrated production, enhancing spatial resolution and reducing phase shift issues across pixels.

Implementation Method 1

an antenna for receiving terahertz radiation modulated by a signal at a modulation frequency

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

each path comprising a capacitive element and at least one first switch controlled by a first signal at said modulation frequency

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 3

each path further comprises a first resistive element

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP3047301B1Terahertz image sensor
Publication Date: 2018.08.01 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP3047301B1 patent drawingFigure 1~4
  • EP3047301B1 patent drawingFigure 5~9
  • EP3047301B1 patent drawingFigure 10~14

AI summary

The invention relates to a terahertz image matrix sensor comprising a matrix of pixels and comprising, for each pixel, an antenna (32) for receiving a terahertz radiation modulated by a signal at a modulation frequency and a synchronous filter (40) with N pathways, where N is an integer greater than or equal to 4, each pathway comprising a capacitive element and at least one first breaker controlled by a first signal at said modulation frequency.