KIEEME 2020, Pyeongchang, Korea
July 8 - 10, 2020 (Wed. - Fri.), Phoenix Park
Wi-Fi Energy-Harvesting Metamaterial and Ionic Thermoplastic Polyurethance Based Wireless VOCs Sensor System
Hojin Lee (Invited Talk)
Abstract
Metamaterials, that possesses powerful ability to
manipulate the electromagnetic (EM) waves exhibiting the unprecedented EM
properties, have attracted considerable attention as new sensing platform having
great sensing capability of high sensitivity, rapid sensing response, and
non-destructive detection. However, conventional metamaterial based sensor
systems require expensive and complicated measurement system that limits
real-time application. In this paper, wireless-powered volatile organic
compound (VOCs) sensor is presented by combining energy-harvesting metamaterial
(EH-MM) as wireless sensing platform and ionic thermoplastic polyurethane
(i-TPU) electrolyte as a VOCs sensing material. Especially, to accomplish the
practical wireless-powered sensing system, proposed EH-MM based sensor is
designed to operate by harvesting the widespread commercial 2.4 GHz Wi-Fi
source. When i-TPU electrolyte was exposed to VOCs, diffusivity of ionic liquid
increases leading to decrease in resistance of i-TPU electrolyte that can be
identified with differential harvested energy level induced from resonance
property variation of the EH-MM. By analyzing variation of the
energy-harvesting rate as output DC voltage levels, proposed sensor system
could provide sensitive and accurate VOCs sensing results without complicated analyzing
system. Also, using multi-analyte sensing capability of i-TPU electrolyte, the EH-MM
sensor could classify differential VOCs including toluene, hexane, ethanol, and
acetone that causes harmful effects for human by simply displaying the
differential output voltage levels. Furthermore, the EH-MM sensor shows fast
responses (< 1 sec), wide range of VOCs concentration (> 1000 ppm) and high
stability (> 1 month) in ambient condition. As a result, a novel method for
designing the simple and portable VOCs sensing system is presented offering the
satisfactory sensing abilities with easily accessible sensing platform. It is
expected that the proposed sensor system is expected to offer new route to
real-time and wireless sensor systems which make it possible for the proposed
sensor to be widely used in the various sensing applications.
