Zero Power Plasmonic MEMS Relay for Passive Sensing
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Solution Overview
Problem
Current sensors require continuous power and cannot operate effectively in low or zero-power conditions, limiting their deployment for long-term or remote operations without battery replacement or a power source.
Innovation Solution
A zero-power plasmonic microelectromechanical system (MEMS) device that senses electromagnetic radiation and performs signal processing using the energy from detected radiation, featuring a plasmonically-enhanced MEMS relay with bimaterial legs for temperature compensation and a design allowing it to switch between ON and OFF states based on radiation presence, consuming less than 10 nW of power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If active electronics are used in sensors, then sensing capability and signal processing are improved, but power consumption increases and continuous operation requires power source
Solution Approach 1:
The patent replaces active electronic sensing systems with a passive mechanical MEMS relay system that uses electromagnetic radiation to directly actuate mechanical components. The plasmonic absorber converts incident radiation into thermal energy, which causes thermal expansion of the bimaterial legs, mechanically opening or closing the relay contacts without requiring electronic power consumption for sensing or signal processing.
Solution Approach 2:
The sensor system uses the energy from the detected electromagnetic radiation itself to power the switching operation. The absorbed radiation heats the bimaterial legs, which automatically actuate the relay contacts based on the radiation presence, eliminating the need for external power sources during operation.
2Reliability
If continuous power is supplied to sensors, then detection reliability is improved, but operational duration without battery replacement is limited
Solution Approach 1:
The system operates in a periodic manner, remaining in a low-power standby state and activating only when electromagnetic radiation is detected. The MEMS relay switches between open and closed states based on radiation presence, allowing the sensor to maintain reliability during active detection while consuming minimal power during idle periods, thereby extending operational duration.
3Measurement precision
If thermal isolation regions are added to compensate for temperature changes, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent utilizes thermal expansion of bimaterial legs with different coefficients of thermal expansion to achieve temperature compensation. The inner legs expand more than the outer legs when heated, causing the head to deflect in a direction that compensates for temperature-induced measurement errors. This passive thermal compensation mechanism is integrated into the relay structure without requiring additional active components.
Solution Approach 2:
The relay structure employs composite bimaterial legs consisting of layers with different thermal expansion coefficients. These composite materials are designed to exhibit controlled thermal response, where the differential expansion between layers creates the desired compensating deflection. The composite structure achieves temperature compensation through material selection rather than adding complex mechanical compensation mechanisms.
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
The device achieves high sensitivity and low false positive rates, enabling continuous monitoring and detection of various radiation sources, including vehicular exhaust, gunfire, and human presence, with the ability to identify unique targets and operate for extended periods without power replenishment.
Implementation Method 1
The inner pair of legs are attached to opposite sides of the head, while the outer pair of legs are attached to the substrate and disposed adjacent to the inner pair of legs... The bimaterial legs each comprise a stack of at least two materials having different thermal expansion coefficients.
Implementation Method 2
The head includes a plasmonic absorber that absorbs electromagnetic radiation within a spectral band selected for detection of a target. The absorption of electromagnetic radiation within the spectral band causes movement of the head.
Data Source
AI summary
A zero-power plasmonic microelectromechanical system (MEMS) device is capable of specifically sensing electromagnetic radiation and performing signal processing operations. Such devices are highly sensitive relays that consume no more than 10 nW of power, utilizing the energy in detected electromagnetic radiation to detect and discriminate a target without the need of any additional power source. The devices can continuously monitor an environment and wake up an electronic circuit upon detection of a specific trigger signature of electromagnetic radiation, such as vehicular exhaust, gunfire, an explosion, a fire, a human or animal, and a variety of sources of radiation from the ultraviolet to visible light, to infrared, to terahertz radiation.