Rotman-Lens Rectenna Switching for Wide-Angle mmWave Energy Harvesting

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Solution Overview

Problem

Current mmWave energy harvesting systems face challenges in providing high gain and large angular coverage due to the directional dependence of mmWave communications, requiring costly and lossy active devices for beamforming, and impractical large Butler matrices at higher frequencies.

Innovation Solution

The implementation of a Rotman-Lens-based rectenna system with a switch-controlled dual phased backend, allowing for energy harvesting and backscattering modes, which focuses energy into beam ports and uses power management circuits for quasi-isotropic RF combining, enabling high gain and wide angular coverage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If large aperture antennas are used to harvest enough electromagnetic energy from mmWave bands, then energy harvesting capability is improved, but angular coverage becomes limited and system complexity increases

Engineering Contradiction:

Improveenergy harvesting capabilityVSAvoidangular coverage

Core Design Contradiction:

Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The antenna array is divided into multiple independently controllable antenna elements, each contributing to the overall energy harvesting capability while allowing individual beamforming control to achieve wide angular coverage through coherent combining

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system incorporates a dual-mode backend that can operate in either energy harvesting mode or backscattering mode, allowing the same antenna array to serve multiple functions and adapt to different operational requirements

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of operation

If active devices are used for beamforming in mmWave systems, then beam control capability is improved, but system cost and energy loss increase

Engineering Contradiction:

Improvebeam control capabilityVSAvoidsystem energy loss

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

The system uses passive beamforming techniques where the antenna array itself performs beamforming through constructive interference of electromagnetic waves, eliminating the need for active phase shifters and amplifiers that consume energy

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces active electronic beamforming components with a passive mechanical-like structure (the antenna array geometry and passive combining network) that achieves beam control through physical wave interference rather than active electronic manipulation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If Butler matrices are implemented at higher frequencies for wide angular coverage, then angular coverage is improved, but fabrication complexity and cost increase significantly

Engineering Contradiction:

Improveangular coverageVSAvoidfabrication complexity

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent extracts the beamforming function from complex high-frequency Butler matrices and implements it through a simplified passive combining network that works effectively at mmWave frequencies without requiring ultra-precise fabrication tolerances

Inventive Principle:

Principle #2Taking out (Extraction)

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 solution provides energy-autonomous IoT devices capable of operating in 5G communication systems with increased power transmission and mobility, supporting digital twinning technologies in smart cities and agriculture by enabling fully-energy-sustained IoT sensors with scalable and flexible mmWave RF tags.

Implementation Method 1

a Rotman Lens having a beam port side and an antenna side in electrical communication with the one or more antenna

Methodology Applied

Scientific EffectLens focusing: Lens

Implementation Method 2

mm-wave backscattering and energy harvesting systems utilizing a Rotman-Lens-based rectenna system

Methodology Applied

Scientific EffectRectification: Rectenna

Data Source

PatentUS12199346B2High gain and large beamwidth rotman-lens-based and mm-wave backscattering and energy harvesting systems and associated methods

Publication Date: 2025.01.14 GEORGIA TECH RES CORP

AI summary

The disclosed technology includes device, systems, techniques, and methods for mm-wave backscattering and energy harvesting systems utilizing a Rotman-Lens-based rectenna system. An mm-wave backscattering and energy harvesting system can include one or more antenna, a Rotman Lens having a beam port side and an antenna side in electrical communication with the one or more antenna, and a switching network in electrical communication with the beam port side of the Rotman Lens. The switching network can be configured to cause the system to operate in either a backscattering mode or an energy harvesting mode.