Reflectarray Design Method for 360-Degree Phase Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional reflectarrays face challenges in achieving a wide range of reflection phases, particularly around plus and minus 180 degrees, leading to unachievable reflection phases and reduced wave characteristics due to complex manufacturing processes and narrow gap requirements.

Innovation Solution

A design method for a reflectarray that sets the element spacing and patch sizes uniformly across elements, allowing for continuous variation of reflection phases across 360 degrees by adjusting the element spacing, thereby simplifying the structure and avoiding the need for multi-layered configurations.

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 range of achievable reflection phases is improved, but the device complexity and manufacturing cost increase due to multiple electrically conducting layers

Engineering Contradiction:
Improverange of reflection phasesVSAvoidnumber of electrically conducting layers
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent changes the geometric parameters of uniform mushroom-like structures (patch size, gap size, via length, substrate thickness) to achieve different reflection phases. By varying these parameters within a single-layer configuration, the patent achieves a wide range of reflection phases without requiring multiple electrically conducting layers, thus resolving the contradiction between adaptability and device complexity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the reflection phase control function across multiple identical mushroom-like structures by varying their individual geometric parameters. Each structure is designed with specific parameter values to achieve the desired reflection phase distribution, eliminating the need for multiple conducting layers while maintaining phase control versatility

Inventive Principle:
Principle #1Segmentation

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:

Instead of adjusting only patch size, the patent changes multiple geometric parameters including gap size, via length, and substrate thickness to achieve desired reflection phases. This approach allows maintaining adequate gap sizes that are manufacturable while still achieving the required phase control through coordinated parameter variations

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If uniform element structures are used with adjusted element spacing to achieve continuous reflection phase variation, then the device complexity is reduced, but the element spacing must be precisely controlled which increases manufacturing difficulty

Engineering Contradiction:
Improvestructure uniformityVSAvoidelement spacing
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent employs multiple geometric parameters (patch size, gap size, via length, substrate thickness) that can be independently controlled during manufacturing. By providing multiple adjustment degrees of freedom, the patent reduces sensitivity to element spacing variations while maintaining the ability to achieve continuous reflection phase variation, thus resolving the contradiction between device complexity and manufacturing precision

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 approach enhances the reflection characteristic of the reflectarray by allowing for a broader range of reflection phases, simplifying the manufacturing process, and maintaining consistent capacitance and inductance values across all elements.

Implementation Method 1

Each of the elements is formed by a structure that reflects the radio wave... In order to suitable reflect radio waves in a direction of a desired reflection angle θr, each of the radio waves that is reflected by the corresponding element is required to have a suitable reflection phase

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

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 3

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

Methodology Applied
Scientific EffectInductance: Inductor

Data Source

PatentEP2822097B1Reflect array and design method
Publication Date: 2020.02.19 NTT DOCOMO INC
  • EP2822097B1 patent drawingFigure 1
  • EP2822097B1 patent drawingFigure 2
  • EP2822097B1 patent drawingFigure 3

AI summary

A reflectarray that reflects an incident wave in a desired direction is such that a plurality of elements is disposed on a substrate having a surface which is perpendicular to a predetermined axis. A method of designing the reflectarray obtains a reflection phase of the elements as a function of a design parameter, when a radio wave enters the elements which are arranged, and stores a relationship between the reflection phase and the design parameter in a memory, wherein any of the design parameter among a size of element spacing, a size of a patch of the element, and a size of a gap between the patches of the neighboring elements is equally set for the elements. The method repeatedly determines, for each of the elements, the design parameter of a specific element in accordance with the relationship. The function of the design parameter has a range which is substantially equal to 360 degrees with respect to a predetermined numerical range of the design parameter, wherein the reflection phase is the continuously varying function with respect to the element spacing, and wherein the function is a continuous function (which indicates a two resonance characteristic) such that two resonant points (the element spacing which causes resonance) occur at which the reflection phase becomes zero.