Micromachined water vapor sensors: a review of sensing technologies

摘要

The measurement of water vapor is important in many applicationsnranging from predicting changes in the weather to ensuring heating andncooling comfort in homes. In manufacturing, water vapor measurementsnhelp to control performance properties of engineered materials andnoptimize fuel efficiency in power generation. This paper presents antechnology review of water vapor sensors and manufacturing techniques.nMicromachining, more commonly known as MEMS or microelectromechanicalnsystems, is an enabling technology based upon standard semiconductornmanufacturing. MEMS technology makes possible solid-state sensors withngreatly reduced power consumption and low operating voltage that arenfully compatible with digital electronics and can be manufactured innhigh volumes at low cost. A water vapor microsensor just becomes anothernpart on the circuit board. A "technology roadmap" for water vapornmicrosensors is defined where the sensing technologies have beennorganized into four major transduction schemes: capacitive,nmass-sensitive, optical and resistive. Sensing element type, keyngeometric features and excitation scheme provides furthernclassification. Operating principles and general performancencharacteristics are also presented