Multi-beam reflectarray using segmented element groups for directional control

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Solution Overview

Problem

Conventional reflectarrays struggle to direct radio waves in multiple desired directions effectively, often resulting in either a strong, narrow beam or a weak, broad beam, limiting the area where communication quality can be improved.

Innovation Solution

A multi-beam reflectarray design that uses mushroom-like structures with adjustable reflection phases to reflect incident radio waves in multiple desired directions by varying the size and position of elements, allowing for a balance between beam strength and width.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the size of the reflectarray is enlarged to increase reception level, then the intensity of the reflected wave is increased, but the beam width becomes smaller

Engineering Contradiction:
Improveintensity of reflected waveVSAvoidbeam width
Core Design Contradiction:
Illumination intensityVSArea of moving object

Solution Approach 1:

The reflectarray is divided into multiple element groups, where each group is responsible for reflecting radio waves in a specific direction. This segmentation allows the system to maintain multiple beams simultaneously, resolving the contradiction between beam intensity and beam width by distributing the function across separate element groups rather than using a single large reflectarray.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The reflectarray structure is designed to perform multiple functions by reflecting radio waves in multiple desired directions simultaneously. Each element group within the reflectarray can be configured to reflect waves at different angles, enabling the system to serve multiple communication directions with a single device, thus maintaining both intensity and width coverage.

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

2Area of moving object

If the size of the reflectarray is reduced to increase beam width, then the area coverage is improved, but the reception level becomes smaller

Engineering Contradiction:
Improvebeam widthVSAvoidintensity of reflected wave
Core Design Contradiction:
Area of moving objectVSIllumination intensity

Solution Approach 1:

By segmenting the reflectarray into multiple element groups, each group can be optimized for its specific directional function. This allows the overall system to achieve wide area coverage through multiple beams while each individual beam maintains sufficient intensity from its dedicated element group.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple element groups are combined within a single reflectarray structure, where each group contributes to a different reflected beam. The combination of these element groups enables the system to achieve both wide area coverage and adequate reception level by summing the contributions of multiple beams across different directions.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If a conventional reflector is inclined to enlarge the angle of incidence and reflection, then the incident wave can be directed to a desired direction, but safety concerns arise due to the high placement

Engineering Contradiction:
Improvedirection control of reflected waveVSAvoidsafety risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The reflectarray changes the fundamental parameter of reflection by using programmable phase control in each element group. Instead of relying on physical inclination to change reflection angles, the system electronically adjusts the phase of each element to achieve desired reflection directions, maintaining safety while enabling precise direction control.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The mechanical inclination method is replaced with an electronic phase control system. The reflectarray uses phase shifters and signal processing to control the direction of reflected waves without any physical tilting or mechanical adjustment, eliminating safety risks associated with high-place inclination while maintaining directional control capability.

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

4Adaptability or versatility

If plural elements are used to control reflection phase, then the angle of reflection can be controlled, but the device complexity increases

Engineering Contradiction:
Improvereflection phase controlVSAvoidnumber of elements
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The reflectarray is segmented into multiple element groups, where each group contains a manageable number of elements configured for a specific reflection direction. This segmentation reduces the complexity of controlling individual elements by organizing them into functional groups, making the system more adaptable while keeping device complexity manageable through modular design.

Inventive Principle:
Principle #1Segmentation

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 multi-beam reflectarray achieves the ability to direct radio waves in multiple desired directions, enhancing communication quality by securing both beam strength and width, thereby improving reception levels in a broader area.

Implementation Method 1

a reception level is lowered. For this reason, there has been a technique for transmitting a reflected wave to a location difficult for a radio wave to reach by disposing a reflection plate (reflector) at a high place

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP2624364B1Multi-beam reflectarray
Publication Date: 2017.07.19 NTT DOCOMO INC
  • EP2624364B1 patent drawingFigure 1
  • EP2624364B1 patent drawingFigure 2
  • EP2624364B1 patent drawingFigure 3

AI summary

A multi-beam reflectarray includes two or more element arrays including plural elements aligned along a predetermined direction. The multi-beam reflectarray is such that, in each of a first element group and a second element group included in at least one of the element arrays, a difference between phases of radio waves reflected by corresponding two elements is in proportion to a first product of a distance between the two elements and a value of a trigonometric function with respect to an angle of reflection by the two elements, and a distance between neighboring elements in the first element group is equal to a product of a rational number and a distance between neighboring elements in the second element group.