Memristor RIS Cell for Non-Volatile Beamforming Control

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Solution Overview

Problem

Conventional reconfigurable intelligent surfaces (RISs) for wireless communication face challenges with high static energy consumption due to the need for continuous power to maintain switch states, and RF MEMS devices face issues with high switching voltages and fabrication complexity, hindering the development of greener 6G technologies.

Innovation Solution

The use of memristors connected in series with conductive regions of antennas in RIS cells allows for low power consumption, non-volatile switching, and fast switching times, achieving reconfigurability without high switching voltages, and enabling multilevel resistance states for advanced control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional reconfigurable cells with PIN diodes, MEMS, liquid crystals, or varactor diodes are used, then reconfigurability is achieved, but static energy consumption is high due to continuous power spending to maintain switch states

Engineering Contradiction:
ImprovereconfigurabilityVSAvoidstatic energy consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by stationary object

Solution Approach 1:

The memristor device inherently maintains its resistance state without requiring external power, utilizing its own physical properties (resistive switching) to preserve configuration information, thereby eliminating the need for continuous power spending

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention changes the fundamental operating parameter from volatile switching (requiring continuous power) to non-volatile resistive switching, where the memristor transitions between high and low resistance states to control antenna impedance without continuous power supply

Inventive Principle:
Principle #35Parameter changes

2Use of energy by stationary object

If RF MEMS devices are used to achieve low power consumption, then static energy consumption is reduced, but switching voltages become high (10-100 V) and fabrication complexity increases

Engineering Contradiction:
Improvepower consumptionVSAvoidfabrication complexity
Core Design Contradiction:
Use of energy by stationary objectVSDevice complexity

Solution Approach 1:

The memristor can be fabricated using standard semiconductor processing techniques that are already widely available, replacing the complex RF MEMS fabrication process with more accessible and simpler manufacturing methods

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention replaces the mechanical moving parts of RF MEMS with a solid-state memristor device that achieves switching through electrical resistance changes, eliminating mechanical complexity and high voltage requirements

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

3Adaptability or versatility

If conventional reconfigurable cells are used, then reconfigurability is achieved, but switching time is slow and frequency operation is limited

Engineering Contradiction:
ImprovereconfigurabilityVSAvoidswitching time
Core Design Contradiction:
Adaptability or versatilityVSSpeed

Solution Approach 1:

The memristor enables rapid transitions between resistance states through periodic voltage pulses, achieving fast switching times in the microsecond range that support higher frequency operations compared to conventional cells

Inventive Principle:
Principle #19Periodic action

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 reduces static energy consumption, enables fast switching times, and allows for reconfigurability at higher frequencies, supporting efficient beamforming and radiation control in RISs for 6G wireless communications.

Implementation Method 1

the memristor by being electrically connected in series with the respective conduction region of the antenna, it can allow for controlling the resistivity of the combination of the conduction of the region and the memristor, and hence, for controlling the electrical and magnetic properties of the antenna that comprises said conduction region

Methodology Applied
Scientific EffectMemristive effect: Electrical Resistance

Data Source

PatentEP4576430A1Cell for transmit array or reflect array, transmit array or reflect array, and system
Publication Date: 2025.06.25 INESC TEC INST DE ENGENHARIA DE SISTEMAS E COMPUTADORES TECHA E CIENCIA
  • EP4576430A1 patent drawingFigure 1~2A
  • EP4576430A1 patent drawingFigure 2B~3A
  • EP4576430A1 patent drawingFigure 3B~4

AI summary

A cell for a transmit array or a reflect array, the cell comprising an antenna which is a patch antenna or a ring resonator antenna, and at least one memristor (13, 13a, 13b) which is electrically connected in series with a respective conductive region (11, 111, 211, 311, 411, 418, 840P, 840N) of the antenna. A transmit array or a reflect array comprising a plurality of cells. A system comprising the array and further comprising a digital controller and, connectable to the digital controller, a corresponding interface circuit for each cell of the plurality of cells, wherein the digital controller in combination with the corresponding interface circuit are configured to controllably set the at least one memristor (13, 13a, 13b) of each cell to any of a first resistivity state and a second resistivity state.