Dual-Ring MEMS RIS Unit Cells for Analog Phase Tuning

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Solution Overview

Problem

Existing reconfigurable intelligent surfaces (RIS) using PIN diodes or varactors for electromagnetic wave manipulation are limited to binary or discrete states, lacking seamless analog tuning and requiring complex biasing and wiring, which complicates design and increases potential failure points.

Innovation Solution

Integration of microelectromechanical systems (MEMS) actuators with dual ring cantilevers for electrothermal actuation, enabling continuous analog tuning and simplified assembly by incorporating MEMS into the fabrication process, eliminating the need for complex biasing and wiring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If PIN diodes or varactors are used for electromagnetic wave manipulation, then the RIS can achieve binary or discrete state control, but the tuning continuity is limited and complex biasing and wiring are required

Engineering Contradiction:

Improvetuning continuityVSAvoidbiasing and wiring complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes the complex biasing network and wiring from the RIS unit cell structure. By using MEMS cantilevers with electrothermal actuation, the control mechanism is simplified to direct voltage application to the cantilever, eliminating the need for complex biasing circuits and reducing wiring complexity while maintaining analog tuning capability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the electrical switching mechanism (PIN diodes/varactors) with a mechanical actuation system (MEMS cantilever). The electrothermal actuation causes the cantilever to physically move and alter the electromagnetic path, providing analog tuning through mechanical displacement rather than electrical state switching

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If PIN diodes or varactors are used for electromagnetic wave manipulation, then the RIS can achieve discrete state control, but the analog tuning capability is lacking

Engineering Contradiction:

Improveanalog tuning capabilityVSAvoidfailure points

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The MEMS cantilever structure is self-contained and requires no external biasing network to function. The electrothermal actuation is achieved by directly applying voltage to the cantilever, which generates heat and causes expansion, enabling the structure to self-regulate its position without additional control circuits that could introduce failure points

Inventive Principle:

Principle #25Self-service

3Ease of operation

If complex biasing and wiring are used in RIS, then binary or discrete state control is achieved, but the design complexity increases

Engineering Contradiction:

Improvedesign simplicityVSAvoiddesign complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges the actuation mechanism and the electromagnetic control element into a single integrated MEMS cantilever structure. The cantilever itself serves as both the actuator and the electromagnetic path modifier, eliminating the need for separate biasing networks and control wiring, thereby simplifying the overall design

Inventive Principle:

Principle #5Merging (Combining)

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

Achieves seamless, uninterrupted analog tuning over a large range, enhancing adaptability and functionality of RIS by providing precise control over reflected beams with improved reliability and scalability through CMOS compatibility.

Implementation Method 1

the first non-anchored portion being curved upward with a first amount of curvature, when heated by a first non-zero amount of joule heating

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

the first non-anchored portion being curved upward with a first amount of curvature, when heated by a first non-zero amount of joule heating

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS20260051872A1Dual ring microelectromechanical systems integration for analog tunability in reconfigurable intelligent surfaces

Publication Date: 2026.02.19 DELL PROD LP

AI summary

The technology described herein is directed towards a reconfigurable intelligent surface (RIS) based on microelectromechanical systems (MEMS) technology, in which metallic MEMS micro-actuators are integrated into unit cells of the RIS. Dual ring-shaped metallic cantilevers, resulting from unit cell fabrication, operate as electrothermal actuators in the unit cell's resonating pattern. A controlled voltage can be separately applied to each ring-shaped cantilever, deforming (bending up) each ring at its non-anchored (free) portion from its generally flat non-actuated state via joule heating. The amount of vertical displacement of the free portion of each ring when voltage is applied separately changes the structure of the unit cell's geometry based on each amount of applied voltage, whereby analog-like tuning of the unit cell's characteristics (including phase shift) is obtained. When combined with the voltage-controlled phase shifts of other unit cells of the RIS, beamforming of a reflected incoming electromagnetic wave is facilitated.