Mitigating Beam Squint in Millimeter Wave Phased Arrays

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Solution Overview

Problem

Beam squint in phased array antennas used in wireless communication systems limits bandwidth and decreases channel capacity, as existing channel estimation algorithms do not account for frequency-dependent beam direction changes, leading to increased channel estimation errors.

Innovation Solution

Implementing true time-delay (TTD) devices, such as optical or electronic methods using MEMS, to eliminate beam squint by introducing time delays corresponding to linear phase responses, and designing beamforming codebooks that optimize array gain and compensate for beam squint, particularly in millimeter wave (mmWave) frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If phased array antennas are used in millimeter wave systems, then spectrum utilization at higher frequencies is enabled, but beam squint occurs that limits bandwidth and decreases channel capacity

Engineering Contradiction:

Improvespectrum utilizationVSAvoidchannel capacity

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent changes the beamforming parameters by introducing frequency-dependent time delays instead of fixed phase shifts. This parameter change allows the beam direction to be compensated across different frequencies, eliminating beam squint while maintaining millimeter wave spectrum utilization.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces true time-delay devices as an intermediary component between the signal source and the antenna array. These TTD devices act as mediators that introduce frequency-dependent delays to compensate for beam squint, thereby preserving channel capacity while enabling high-frequency operation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If conventional channel estimation algorithms are used, then algorithm simplicity is maintained, but beam squint compensation is not achieved leading to increased estimation errors

Engineering Contradiction:

Improvealgorithm complexityVSAvoidchannel estimation accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent transforms the static channel estimation approach into a dynamic one by incorporating frequency-dependent time delay compensation. The channel estimation algorithm adapts to different frequencies by applying appropriate TTD corrections, improving accuracy without excessive complexity increase.

Inventive Principle:

Principle #15Dynamics

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 effectively maximizes channel capacity and reduces the effects of beam squint, enabling efficient spectrum utilization at higher frequencies by accurately accounting for frequency-dependent beam directions and optimizing array performance.

Implementation Method 1

Implementing true time-delay (TTD) devices, such as optical or electronic methods using MEMS, to eliminate beam squint by introducing time delays corresponding to linear phase responses

Methodology Applied

Scientific EffectTime delay:

Implementation Method 2

Implementing true time-delay (TTD) devices, such as optical or electronic methods using MEMS

Methodology Applied

Scientific EffectOptical to electromagnetic transformation:

Data Source

PatentUS10819405B2Mitigating beam squint in millimeter wave wireless communication systems

Publication Date: 2020.10.27 UNIV OF NOTRE DAME DU LAC

AI summary

A method for managing beam squint in a phased antenna array system operating at millimeter wavelengths using carrier aggregation includes determining a minimum array gain threshold, determining an upper bound for a fractional bandwidth for a fixed number of antennas, and constructing a codebook with a predetermined coverage range based on at least one of an angle of arrival or an angle of departure and further based on the upper bound. The method further includes performing carrier aggregation for the fixed number of antennas and selecting at least two antennas based on the codebook.