Electro-Optical Microwave Frequency Measurement

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Solution Overview

Problem

Conventional microwave signal measurement techniques fail to accurately measure frequencies across a wide band simultaneously due to low spectral resolution, slow scanning speed, and limited bandwidth, often omitting time-varying signals and requiring high hardware resources.

Innovation Solution

A method and system utilizing an electro-optical crystal to convert microwave signals into optical signals, detected by a single-photon detector and processed using a Fourier transform algorithm, enabling high-resolution frequency measurement across a wide bandwidth through phase, polarization, or intensity modulation, and achieving real-time processing with low sampling rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional microwave measurement techniques are used, then measurement simplicity is maintained, but measurement precision and bandwidth are limited

Engineering Contradiction:

Improvefrequency measurement precisionVSAvoidmeasurement system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces conventional electronic microwave measurement systems with an electro-optical measurement system. The microwave signal is converted to an optical signal through electro-optical modulation, where the microwave electric field modulates the polarization state of light passing through an electro-optical crystal. This optical signal is then detected by single-photon detectors, enabling high-precision frequency measurement without the bandwidth and precision limitations of traditional electronic systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement domain from electrical parameters to optical parameters. By using the electro-optical effect, the microwave signal's frequency information is encoded in the polarization state of light rather than directly measuring electrical voltage or current. This parameter transformation enables measurement of microwave frequencies up to hundreds of GHz with Fourier limit spectral resolution, overcoming the inherent limitations of electronic measurement systems.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If wideband frequency measurement is implemented, then measurement bandwidth increases, but data processing requirements increase

Engineering Contradiction:

Improvemeasurement bandwidthVSAvoiddata processing load

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent extracts only the essential frequency information from the wideband microwave signal through electro-optical modulation. Instead of capturing and processing all signal components, the system converts the microwave frequency information into optical polarization states, which are then detected by single-photon detectors. This extraction approach reduces the data processing load while maintaining wide measurement bandwidth capability.

Inventive Principle:

Principle #2Taking out (Extraction)

3Measurement precision

If high spectral resolution is achieved, then frequency measurement accuracy improves, but measurement time increases

Engineering Contradiction:

Improvespectral resolutionVSAvoidmeasurement time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces time-consuming electronic spectrum analysis with optical-based frequency measurement. The electro-optical crystal instantaneously modulates the light polarization state according to the microwave signal frequency, and single-photon detectors provide immediate detection. This substitution eliminates the need for slow electronic scanning and Fourier transform processing, achieving Fourier limit spectral resolution in real-time.

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 approach allows for accurate measurement of microwave frequencies up to hundreds of GHz with Fourier limit spectral resolution, overcoming bandwidth limitations and reducing data processing requirements, enabling real-time recognition of wideband frequency signals.

Implementation Method 1

generating, when a light source irradiates an electro-optical crystal disposed in a microwave electric field, to-be-detected emergent light under an action of the electro-optical crystal

Methodology Applied

Scientific EffectElectro-optical effect: Electro-Optic Effects

Data Source

PatentUS11754601B2Measuring frequency of microwave signal

Publication Date: 2023.09.12 SHANXI UNIV

AI summary

A frequency measurement method and a system thereof are provided. The method includes: generating to-be-detected emergent light under an action of the electro-optical crystal when a light source irradiates an electro-optical crystal disposed in the microwave electric field; detecting, by a single-photon detector, the to-be-detected emergent light to obtain a detection result of the single-photon detector; and determining a frequency of the microwave signal based on the detection result of the single-photon detector and a Fourier transform algorithm.