Rydberg Molecule Microwave Interferometry for Direction Finding

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Solution Overview

Problem

Existing microwave sensing technologies lack sensitivity and effectiveness in determining the propagation direction and electric-field strength of microwave wavefronts, limiting their performance in applications such as geolocation and antenna orientation.

Innovation Solution

A Rydberg-molecule-based microwave direction finder employing passive correlative interferometry for high sensitivity, angular resolution, and selective filtering, utilizing a probe and control laser to transition atoms between states and create a microwave interference pattern captured by a camera to determine direction and intensity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional microwave sensors are used, then the device structure is simple, but the sensitivity and measurement precision are limited

Engineering Contradiction:
Improvedirection and intensity measurement sensitivityVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces Rydberg atoms as an intermediary medium between the microwave field and the detection system. The atoms are excited by lasers to Rydberg states, which then interact with microwave photons to produce measurable absorption signals. This intermediary approach enables highly sensitive microwave detection while keeping the overall device structure manageable.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces conventional electronic microwave sensing mechanisms with a quantum optical system. Lasers are used to excite atoms to Rydberg states, and microwave detection is achieved through optical absorption measurements rather than traditional electrical field measurements. This substitution enables superior sensitivity while maintaining device feasibility.

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

2Measurement precision

If conventional microwave sensors are used, then the device complexity is low, but the angular resolution is insufficient

Engineering Contradiction:
Improveangular resolutionVSAvoidinterferometry system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs a two-lens interferometric system that segments the microwave detection function into two separate optical paths. Each lens focuses microwave-induced atomic transitions to different spatial locations, creating an interference pattern that encodes angular information. This segmentation enables precise angle measurement through correlation analysis of the two detection channels.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transforms angular measurement from a direct spatial measurement into a correlation analysis in signal space. By measuring the relative phases and amplitudes of interference patterns from two different optical paths, the system determines arrival angles with high precision. This dimensional transformation enables superior angular resolution beyond what single-point sensors can achieve.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If broad bandwidth microwave sensing is implemented, then the adaptability increases, but the selective filtering capability decreases

Engineering Contradiction:
Improvefrequency tuning rangeVSAvoidout-of-band interference
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent exploits the tunable nature of Rydberg atomic transitions to achieve broadband microwave sensing. By adjusting the laser excitation parameters, the Rydberg state energy levels can be tuned to resonate with different microwave frequencies. This parameter control enables wide frequency coverage while maintaining narrow spectral selectivity through the inherent sharpness of atomic transitions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses periodic laser pulsing to probe different microwave frequency components. By synchronizing the laser excitation cycle with the microwave signal period, the system can selectively detect specific frequency components while filtering out others. This periodic probing mechanism enables both broadband coverage and selective filtering through frequency-domain analysis.

Inventive Principle:
Principle #19Periodic action

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

Achieves high sensitivity, selective filtering, and wide bandwidth for microwave direction finding, with sensitivity of -194 dBm/Hz and angular resolution of less than 0.5°, enabling precise geolocation and antenna orientation across a wide frequency range.

Implementation Method 1

A probe laser causes molecules in a ground state to transition to an excited state

Methodology Applied
Scientific EffectOptical absorption: Absorption (EM radiation)

Implementation Method 2

a control laser causes molecules in the excited state to transition to a laser-induced Rydberg state

Methodology Applied
Scientific EffectLaser excitation: Laser

Implementation Method 3

The microwave beams are counter-propagated through the molecules so that they interfere to establish a microwave interference pattern

Methodology Applied
Scientific EffectInterference: Interference

Data Source

PatentEP4176273B1Rydberg-molecule-based microwave direction finding
Publication Date: 2026.03.04 INFLEQTION QUANTUM LLC
  • EP4176273B1 patent drawingFigure 1
  • EP4176273B1 patent drawingFigure 2~3
  • EP4176273B1 patent drawingFigure 4

AI summary

A probe laser beam causes molecules to transition from a ground state to an excited state. A control laser beam causes molecules in the excited state to transition to a laser- induced Rydberg state. Microwave lenses convert a microwave wavefront into respective microwave beams. The microwave beams are counter-propagated through molecules so as to create a microwave interference pattern of alternating maxima and minima. The microwave interference pattern is imposed on the probe beam as a probe transmission pattern. The propagation direction of the microwave wavefront can be determined from the translational position of the probe transmission pattern; the intensity of the microwave wavefront can be determined by the intensity difference between the minima and maxima of the probe transmission pattern.