%0 Journal Article %T Real-Time Remote Monitoring of Temperature and Humidity Within a Proton Exchange Membrane Fuel Cell Using Flexible Sensors %A Long-Sheng Kuo %A Hao-Hsiu Huang %A Cheng-Hao Yang %A Ping-Hei Chen %J Sensors %D 2011 %I MDPI AG %R 10.3390/s110908674 %X This study developed portable, non-invasive flexible humidity and temperature microsensors and an in situ wireless sensing system for a proton exchange membrane fuel cell (PEMFC). The system integrated three parts: a flexible capacitive humidity microsensor, a flexible resistive temperature microsensor, and a radio frequency (RF) module for signal transmission. The results show that the capacitive humidity microsensor has a high sensitivity of 0.83 pF%RH£¿1 and the resistive temperature microsensor also exhibits a high sensitivity of 2.94 ¡Á 10£¿3 ¡ãC£¿1. The established RF module transmits the signals from the two microsensors. The transmission distance can reach 4 m and the response time is less than 0.25 s. The performance measurements demonstrate that the maximum power density of the fuel cell with and without these microsensors are 14.76 mW¡¤cm£¿2 and 15.90 mW¡¤cm£¿2, with only 7.17% power loss. %K flexible humidity microsensor %K flexible temperature microsensor %K radio frequency module %K power density %U http://www.mdpi.com/1424-8220/11/9/8674