Drone Antenna Pattern Measurement for Multipath-Free Power Beams

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Solution Overview

Problem

In environments where radio waves are reflected, such as outdoors, accurately measuring antenna radiation patterns is challenging due to multipath interference, which degrades the efficiency of wireless power transmission to aerial moving bodies.

Innovation Solution

A radio wave measurement system using an aerial moving body, like a drone, that measures the radiation pattern of power transmission radio waves by hovering and moving above the power transmission device, reducing the influence of reflections and allowing for accurate beam shape measurement in a good radio wave environment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If measurement is performed in an anechoic chamber environment, then measurement precision is improved, but device complexity and loss of time increase

Engineering Contradiction:
Improveantenna radiation pattern measurement accuracyVSAvoidanechoic chamber requirement
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a position measurement device as an intermediary component that tracks the three-dimensional position of the aerial moving body. This position information serves as a mediator between the received signal strength and the radiation pattern calculation, enabling accurate measurements without requiring an anechoic chamber environment. The position data compensates for the effects of multipath interference by providing spatial context for signal analysis.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical/physical anechoic chamber structure with a computational approach using a radiation pattern calculation device. Instead of physically eliminating reflections through absorptive materials, the system uses signal processing and position-based calculations to achieve accurate radiation pattern measurements in ordinary environments.

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

2Ease of operation

If measurement is performed in outdoor environments with radio wave reflections, then ease of operation is improved, but measurement precision deteriorates due to multipath interference

Engineering Contradiction:
Improvemeasurement environment accessibilityVSAvoidantenna radiation pattern measurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent moves the measurement probe from ground level to three-dimensional space using an aerial moving body (drone). By measuring radiation patterns in the vertical dimension and all-around horizontal directions, the system captures complete spatial radiation characteristics that cannot be obtained from ground-based measurements, while avoiding ground reflections that cause multipath interference.

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

Solution Approach 2:

The patent uses the aerial moving body to physically replicate the position and orientation of potential receivers in three-dimensional space. By flying the drone to various positions and measuring signal strength at each location, the system creates a spatial map of radiation patterns that accurately represents how the antenna radiates energy in all directions, equivalent to having receivers positioned throughout the space.

Inventive Principle:
Principle #26Copying

3Loss of energy

If beam direction control accuracy is improved, then power transmission efficiency is improved, but device complexity increases

Engineering Contradiction:
Improvewireless power transmission efficiencyVSAvoidbeam control system complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The radiation pattern measurement system serves multiple functions: it characterizes antenna performance, guides beam direction control, and validates power transmission effectiveness. By using the same aerial moving body and measurement infrastructure for both measurement and control purposes, the system avoids duplicating equipment and reduces overall complexity while improving power transmission efficiency through accurate beam steering.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enables accurate measurement of the radiation pattern and improves the efficiency of wireless power transmission by minimizing the impact of multipath interference, allowing for more precise directionality and higher power transfer efficiency.

Implementation Method 1

a power transmission antenna 30 that radiates a radio wave 2

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 2

a radiation direction determiner 22B that determines a direction in which the aerial moving body 3B exists

Methodology Applied
Scientific EffectElectromagnetic wave detection: Electromagnetic Induction

Implementation Method 3

an orientation direction changer 22B that changes an orientation direction of the power transmission antenna 30 into the radiation direction

Methodology Applied
Scientific EffectAntenna orientation control:

Data Source

PatentEP3828559B1Power transmission system to aerial moving body
Publication Date: 2023.12.27 MITSUBISHI ELECTRIC CORP
  • EP3828559B1 patent drawingFigure 1
  • EP3828559B1 patent drawingFigure 2~3
  • EP3828559B1 patent drawingFigure 4~5

AI summary

When a radiation pattern of an antenna is measured in an environment where a radio wave is reflected, it is difficult to measure the radiation pattern with high accuracy due to an influence of multipath. A radio wave measurement system includes: an aerial moving body 3 to move or to hover above a measurement target antenna 30 for radiating a radio wave 2 in a sky direction; and a position measurer 18H to measure a time added position of the aerial moving body. The aerial moving body 3 includes a measurement antenna 14 to receive the radio wave 2 and a radio wave measurer 15 to measure time-added received radio wave data 73H including at least one of an amplitude and a phase of the radio wave 2 received by the measurement antenna 14. The aerial moving body 3 further includes a beam shape data generator 21 to generate radiated radio wave data 71 including the received radio wave data 73H and the radio wave source relative position data 78 representing measurement point data 74H that is a position of the aerial moving body 3 at a point of time when the received radio wave data 73H is measured as a relative position with respect to the measurement target antenna 30.