Sensors are being developed for a growing number of applications based on their capability to be accessed remotely for information via the Internet. The use of temperature, humidity, motion-detecting, and other kinds of sensors is making possible automated homes and buildings and “smart” cars. For effective and efficient connection to the Internet, these Internet of Things (IoT) or Internet of Everything (IoE) devices rely on the use of available wireless bandwidths and miniature antennas capable of receiving relatively high data rates at very low signal levels.
In previewing the requirements of future smart-sensor-driven automated homes, offices, and automobiles, researchers from the Department of Electrical and Computer Systems Engineering at Monash University in Clayton, Australia surveyed the different types of sensors currently being used for IoT and IoE applications. The researchers looked at how different active and passive sensors can be combined to perform a wide range of functions. The report includes details on a number of unconventional electromagnetic (EM) transduction-based sensors—including passive chipless radio-frequency-identification (RFID), crack, and strain sensors—in addition to widely used varieties like pressure, temperature, and gas-detection sensors.
This wide range of chipless sensors can be fabricated on materials that can be formed into planar, lightweight, flexible shapes for ease of installation in factories, office buildings, and residences. The sensors can be readily printed for the low-cost mass production needed for such predicted large volumes for IoT/IoE wireless sensor applications. As the authors note, a great deal of research remains to be done on identifying base materials for fabricating multiple-function RF/wireless sensors for these future applications. See “Smart Sensing,” IEEE Microwave Magazine, November 2015, p. 26.