Available Technology

Novel Solid-State Humidity Sensor

Unparalleled sensitivity, response, recovery time, and robustness
NASA&#8217s novel ceramic dielectric material enables extremely highsensitivity humidity sensing. The ceramic sensing element is robust, can be manufactured using printing processes, and exhibits fast response and recovery speeds with large capacitance and resistance response/change per relative humidity unit change across a wide range of humidity levels in a log-linear response. Preliminary test data conducted in a humidity test chamber show a log-linear measured response in capacitance from 5 nanofarads (at 30% relative humidity, room temperature) to 0.2 millifarads (at 90% relative humidity, room temperature). The inventors discovered the humidity sensing element technology during their efforts to develop next-generation energy storage materials and devices for NASA. The inventors were initially puzzled by large swings in capacitance observed over the course of any given day in one particular dielectric composition, and, ultimately, they were able to trace these unexpected changes in capacitance back to corresponding changes in ambient humidity, even those occurring from breathing and exhalation. The sensor element can be formed using a dielectric ink or paste formulation, also developed by NASA, via traditional screen printing or advanced ink jet, aerosol, or 3D printing methods. The printed sensor element can be very thin, on the order of microns in thickness, with a small footprint, one square centimeter or less.
Patent Abstract: 
NASA&#8217s Marshall Space Flight Center has developed a humidity sensor that offers high sensitivity and extremely fast response and recovery across a range of humidity levels. The sensor is based on a novel ceramic dielectric material that exhibits rapid and large changes in capacitance and resistance with very small changes in water vapor concentration; making it ideal for humidity, dew point, or water vapor concentration sensing applications. The dielectric sensing element is low-cost and can easily be made using standard printed electronics processing and packaging methods. The finished sensor is small and robust, and can be used to for rapid measurements of very small changes in humidity across a range of humidity levels, temperatures and chemical environments. The humidity sensor technology is particularly well suited for market applications requiring extremely high sensitivity, fast response times, and/or use in challenging environments. NASA is currently seeking partners to bring this novel sensor technology to the marketplace.
Benefits 

Very high sensitivity to small changes in relative humidity, dew point, and water vapor concentration

applications 

Aerospace

Automotive

Industrial

Health care

Marine

Consumer

Defense

Reps: 
Patent Number: 
9,745,481
Internal Laboratory Ref #: 
MFS-TOPS-80
Patent Status: 
Patent Issue Date: 
June 13, 2017
Agency
NASA
Region
Southeast
State: 
Alabama
Phone: 
256-544-9151
Email: 
terry.taylor@nasa.gov
Lab Representatives
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