SPIE Photonics West 2020, San Francisco, USA
February 1 - 6, 2020 (Sun. - Thur.), Moscone Centor
Wireless-Powered VOC Sensor based on Wi-Fi Energy-Harvesting Metamaterial with i-TPU
Heejoo Park, Wonwoo Lee, Hyunseung Jung, So Young Kim, Do Hwan Kim, and Hojin Lee
Abstract
In this paper, we propose a wireless-powered VOC sensor system based on energy-harvesting metamaterial combined with ionic thermoplastic polyurethane (i-TPU) channel. The sensor consists of the SRR, rectifier circuit to harvest the RF energy by converting electromagnetic energy into DC voltage, and i-TPU channel to detect VOC with the variation of resistance. For the practical wireless sensing system, we utilized widespread and easily accessible commercial 2.4 GHz Wi-Fi source as external electromagnetic wave energy, and the energy-harvesting metamaterial was designed and optimized to resonate at 2.4 GHz. When i-TPU was exposed to acetone gas as target gas, the diffusivity of ionic liquid (IL) increases leading to decrease in resistance of i-TPU that can be identified with the differential harvested energy induced from variation for resonance property. As a result, according to variation of energy-harvesting rate, the proposed sensor could provide the highly sensitive and ultra-stable wireless VOC sensor system without bulky and complicated measurement system offering great accessibility and simplicity for the sensor systems. In addition, it is expected that the proposed system can be applied to not only for VOC sensors but also for dynamic environmental sensing systems.
