Mushroom Structures for Reflect Array Phase Control

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Solution Overview

Problem

Conventional reflect arrays with mushroom structures struggle to achieve a wide range of reflection phases necessary for directing radio waves effectively, especially when the incident angle is small, due to limitations in the range of reflection phase adjustment.

Innovation Solution

The proposed solution involves a reflect array design that utilizes multiple mushroom structures with varying patch sizes and distances from the ground plate, allowing for increased capacitance and inductance control through the arrangement of patches in multiple layers and varying distances, enabling a broader range of reflection phases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional mushroom structures with single-layer patches are used, then the structure is simple, but the range of reflection phase is limited

Engineering Contradiction:
Improverange of reflection phaseVSAvoidstructure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent transitions from a single-layer patch structure to a multi-layer patch structure, adding the vertical dimension (z-axis) to the conventional planar arrangement. Multiple patches are arranged at different heights above the ground plate, creating a three-dimensional configuration that expands the adjustable parameter space for reflection phase control while maintaining structural manageability.

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

Solution Approach 2:

The patent divides the single patch structure into multiple segmented patches arranged in different layers. Each patch can be independently positioned at different heights and locations, allowing granular control over the electromagnetic response. This segmentation enables broader reflection phase coverage by combining the effects of multiple discrete elements.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the incident angle of radio wave is small, then the reflector can be positioned at lower elevation, but the reflection angle cannot be made large enough to direct the wave in desired direction

Engineering Contradiction:
Improvepositioning easeVSAvoiddirection control capability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent changes the geometric parameters of the mushroom structures, specifically the heights of patches at different positions. By varying patch heights rather than simply tilting the entire reflector surface, the system achieves effective direction control with vertically positioned elements, allowing large reflection angles without compromising positioning safety.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces asymmetry in the vertical positioning of patches within the mushroom structures. Patches at different locations have different heights above the ground plate, creating an asymmetric three-dimensional configuration that enables directional control of reflected waves while maintaining a vertically oriented overall structure.

Inventive Principle:
Principle #4Asymmetry

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 enhances the ability to direct radio waves in desired directions by expanding the range of reflection phases, improving the reflect array's performance even at small incident angles, and reducing spurious reflections.

Implementation Method 1

an inductance L and a capacitance C in an equivalent circuit are adjusted to adjust a resonance frequency to control a reflection phase

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

When the radio wave is reflected by the reflector, it becomes difficult for the reflector to direct the radio wave in a desired direction

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP2362488B1Apparatus having mushroom structures
Publication Date: 2017.04.19 NTT DOCOMO INC
  • EP2362488B1 patent drawingFigure 1
  • EP2362488B1 patent drawingFigure 2A
  • EP2362488B1 patent drawingFigure 2B

AI summary

An apparatus having multiple mushroom structures is disclosed. Each of the multiple mushroom structures includes: a ground plate (21); a first patch (23) provided parallel to the ground plate with a separation of a distance to the ground plate; and a second patch (24) provided parallel to the ground plate with a separation of another distance to the ground plate, which another distance being different from the distance from the first patch to the ground plate, wherein the second patch is a passive element which is capacitatively coupled with at least the first patch.