Reflectarray Element Spacing for 360-Degree Phase Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional reflectarrays using mushroom-like structures face challenges in achieving a wide range of reflection phases, particularly around plus and minus 180 degrees, leading to lower reflection characteristics due to unachievable phase combinations and manufacturing complexities.

Innovation Solution

A reflectarray design that allows for a single-layer wire configuration, where the element spacing determines the reflection phase, enabling simultaneous change in capacitance and inductance values across all elements, thereby covering a 360-degree phase range without the need for multi-layer structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple element structures with different heights, via lengths, or substrate thicknesses are combined to achieve a wide range of reflection phases, then the reflection phase coverage is improved, but the manufacturing complexity and cost increase due to multiple electrically conducting layers

Engineering Contradiction:
Improvereflection phase coverageVSAvoidmanufacturing complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent changes the parameter being adjusted from element structural dimensions (patch height, via length, substrate thickness) to element spacing. By varying the spacing between elements while keeping element structures uniform, the reflection phase can be controlled across a wide range without requiring multiple conducting layers or complex manufacturing processes.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the size of the patch is adjusted to achieve desired reflection phases, then the reflection phase control is improved, but the space between large patches becomes very narrow which cannot be achieved due to processing accuracy limitations

Engineering Contradiction:
Improvereflection phase controlVSAvoidgap between patches
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent transitions from adjusting patch size to adjusting element spacing as the primary means of controlling reflection phase. This parameter change eliminates the need to create excessively narrow gaps between large patches, as the spacing between elements can be freely adjusted without compromising manufacturing feasibility or processing accuracy.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional techniques are used to achieve specific reflection phases, then certain phase values can be obtained, but unachievable reflection phases exist in the vicinity of plus and minus 180 degrees leading to lower reflection characteristics

Engineering Contradiction:
Improvereflection characteristicVSAvoidachievable phase range
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the controlling parameter from patch size to element spacing, which enables continuous adjustment of reflection phase across the full 360-degree range. This overcomes the limitation of conventional techniques where phases near plus and minus 180 degrees were unachievable, thereby improving both the achievable phase range and the overall reflection characteristics.

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

This design simplifies the manufacturing process, improves reflection characteristics by allowing for uniform capacitance and inductance changes, and avoids the formation of excessively narrow gaps, resulting in enhanced radio wave reflection performance.

Implementation Method 1

values of the reflection phases are varied by changing a value of capacitance which is determined by the gap between the elements of the mushroom-like structures

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

a value of inductance which is determined by the length of the via

Methodology Applied
Scientific EffectInductance: Inductor

Implementation Method 3

each of the elements is formed by a structure that reflects the radio wave

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP2822099B1Reflect array, and design method
Publication Date: 2019.05.15 NTT DOCOMO INC
  • EP2822099B1 patent drawingFigure 1
  • EP2822099B1 patent drawingFigure 2
  • EP2822099B1 patent drawingFigure 3

AI summary

A reflectarray reflects an incident wave in a desired direction. The reflectarray includes a substrate including a surface which is perpendicular to a predetermined axis; and at least first and second element groups, wherein the first and second element groups are disposed on the substrate, and include elements that reflect a radio wave. The first element group and the second element group reflect the radio wave with corresponding reflection phases which are different from each other. The radio wave enters while forming an angle other than 0 degrees with respect to the predetermined axis. The elements included in the first element group reflect the radio wave with a first reflection phase, and the elements included in the second element group reflect the radio wave with a second reflection phase, wherein the second reflection phase is different from the first reflection phase.