Description:
Background
The invention of a zero-power Plasmonic Microelectromechanical Infrared Digitizer (PLASMID) that combines sensing, signal processing, and comparator functionalities into a single microsystem capable of producing a quantized output bit in the presence of a specific infrared (IR) spectral signature. The PLASMID is able to sense and digitize the unique IR spectral signatures associated with the exhaust plumes of engines using gasoline or diesel as fuels, and it will enable detection of vehicles such as trucks, cars or even aircraft while consuming no more than 10 nW and maintaining a low false alarm rate (less than 1 per hour). These unique features are achieved by means of fundamental innovation in microelectromechanical system (MEMS), plasmonic and microsystem design. The PLASMID core element is a plasmonically-enhanced MEMS relay (PMR) that is selectively triggered by impinging IR radiation at a specific spectral wavelength.
 
Technology Overview
In this invention, a micromechanical structure has all the fundamental features necessary to implement the IR sensing and comparator functionalities required by the PLASMID architecture:
(i) High sensitivity: IR threshold < 100 nW
(ii) High spectral selectivity: full width at half maximum, FWHM < 10% 
(iii) Immunity to ambient temperature changes and other sources of interfering mechanical stresses
(iv) Fast response time; less than 100 ms to close the contacts upon exposure to IR radiation 
(v) Low subthreshold swing: ~1 pW/dec 
The PLASMID is composed of an array of PMRs, in which each element is designed to respond to a specific spectral wavelength, and produces an output bit only when a specific combination of PMRs is activated by the target IR signature. The probability of false alarms is minimized through the implementation of sophisticated PMR logic topologies.
The PLASMID uses the system battery to charge the load capacitor only when the proper combination of PMRs is activated by the target IR signature. Therefore, the battery only draws power when a target is present. When the target is not present, the power draw is well below 10 nW. Furthermore, threshold tuning and complementary device operation using NO and NC PMRs can be further facilitated by the introduction of body-biased thin-film Aluminum Nitride (AlN) piezoelectric unimorph actuators in the design of the structure, providing a multitude of advantages for the implementation of a sophisticated logic for improved IR signature discrimination.
 
Benefits
- PLASMID exploits the energy in the heated gas molecules themselves to detect and discriminate the presence of the exhaust plume of interest while rejecting background interference from other warm objects. This is accomplished without any additional power source, which directly translates into near-zero standby power consumption.
- High sensitivity and low false positives with zero-power consumption.
- Plasmonic MEMS relays in a passive logic circuit connect the system battery to the load only when exposed to the target IR signature.
 
Applications
- Development of unattended ground sensors
- Development of miniaturized and zero-power combat identification
- Development of wearable sensors that can constantly monitor IR radiation level of surroundings with zero-power consumption
- Development of zero-power sensor nodes of IoT devices
 
Opportunity
- License
- Research collaboration
- Partnering
Patent Information:
Category(s):
-Devices
-Sensors tech
For Information, Contact:
Mark Saulich
Associate Director of Commercialization
Northeastern University
m.saulich@northeastern.edu
Inventors:
Matteo Rinaldi
Zhenyun Qian
Yu Hui
Vageeswar Rajaram
Keywords: