Self-sustainable wireless sensor network for low-temperature application

While environmental monitoring system is an exemplary application for wireless sensor network (WSN), its energy-constraint still remains unresolved issue and needs to be addressed. In this work, a self-sustainable WSN is proposed for low-temperature application. To resolve the energy-constraint issue, a wireless power transfer (WPT) technique, called conformal strongly coupled magnetic resonant (CSCMR) technique, is adopted. At 90 MHz, the RF power transmission efficiency is 84% with 60 mm distance between transmitting and receiving resonators. For the 90 MHz RF power, the rectifier efficiency for the RF to DC power conversion is 69% and 76 at 25 degrees C and -20 degrees C, respectively. For an energy storage unit, a supercapacitor is chosen for the low-temperature application. With the excellent temperature characteristic of the supercapacitor, the effectiveness of the supercapacitor is verified as the energy storage unit operating at -20 degrees C. It is shown that the WSN proposed in this work can operate in perpetuity as long as the circuit components in the WSN do not have any defects.