Differential Coupling in VCO Arrays for Beamforming

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Solution Overview

Problem

Coupled Voltage Controlled Oscillator (VCO) arrays used in Local Oscillator (LO) signal generation for beamforming are limited in differential phase shift generation due to injection locking, which breaks down beyond a certain level, restricting phase difference determinability and susceptibility to noise and interference.

Innovation Solution

Implementing a coupled VCO array with differential circuitry to accommodate differential coupling between VCOs, allowing for improved noise immunity and increased phase difference range through phase inversion circuitry, thereby enhancing beamforming capability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If single-ended coupling is used between VCOs, then device complexity is reduced, but immunity to noise and interference deteriorates

Engineering Contradiction:

Improvecoupling circuit complexityVSAvoidnoise immunity

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent inverts the conventional single-ended coupling approach by implementing differential coupling between VCOs. This inversion transforms the signal representation from single-ended to differential mode, which inherently provides noise immunity through common-mode rejection while maintaining manageable circuit complexity through systematic design.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent employs composite signal structures by combining multiple VCO outputs in a differential configuration. This composite approach creates a robust signal system that leverages the properties of differential signaling to reject common-mode noise and interference, improving reliability without excessive complexity increase.

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If injection locking is used for frequency control, then frequency stability is improved, but phase difference determinability deteriorates beyond certain phase shifts

Engineering Contradiction:

Improvefrequency stabilityVSAvoidphase difference determinability

Core Design Contradiction:

Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

The patent segments the phase difference measurement into multiple ranges by utilizing the properties of coupled VCOs in differential configuration. By dividing the phase measurement space and using the differential output, the system can determine phase differences across a wider range (beyond ±90 degrees) while maintaining frequency stability through injection locking.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary differential coupling mechanism between VCOs that mediates the relationship between frequency control and phase measurement. This intermediary structure allows injection locking to maintain frequency stability while the differential configuration enables extended phase difference determinability through the coupling relationship.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If differential coupling is implemented between VCOs, then immunity to noise and interference is improved, but device complexity increases

Engineering Contradiction:

Improvenoise immunityVSAvoidcoupling circuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the operational parameters of the VCO coupling by transitioning from single-ended to differential mode. This parameter change fundamentally alters the noise rejection characteristics while the systematic implementation keeps the complexity increase manageable through standardized differential circuit design practices.

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

The solution extends beamforming capability by improving immunity to noise and interference, increasing beamforming angles, and reducing phase-steering requirements, resulting in better performance and flexibility.

Implementation Method 1

Injection locking between the individual VCOs that are part of the coupled VCO array and between the VCOs and the external reference signal may limit the differential phase shift generation to a certain level

Methodology Applied

Scientific EffectInjection locking:

Implementation Method 2

mixing LO signals generated through the number of VCOs of the coupled VCO array with signals from antenna elements of an antenna array to introduce differential phase shifts

Methodology Applied

Scientific EffectMixing: Heterodyne

Data Source

PatentUS9531070B2Extending beamforming capability of a coupled voltage controlled oscillator (VCO) array during local oscillator (LO) signal generation through accommodating differential coupling between VCOs thereof

Publication Date: 2016.12.27 INTEGRATED DEVICE TECH INC

AI summary

A method includes implementing a coupled Voltage Controlled Oscillator (VCO) array with a number of VCOs, and mixing Local Oscillator (LO) signals generated through the number of VCOs of the coupled VCO array with signals from antenna elements of an antenna array to introduce differential phase shifts in signal paths coupled to the antenna elements during performing beamforming with the antenna array. The method also includes accommodating differential coupling between the VCOs to improve immunity to noise and/or interference during the beamforming compared to the VCOs accommodating single-ended coupling therebetween.