A CMOS Humidity Sensor for Passive RFID Sensing Applications

Sensors

Fangming Deng¹  Yigang He¹  Chaolong Zhang¹ 

[1] School of Electrical Engineering and Automation, Hefei University of Technology, Hefei 230009, China; E-Mails:

关键词: RFID technology;    passive RFID tag;    humidity sensor;    interface circuit;    phase-locked loop;    CMOS technology;   

DOI  :  10.3390/s140508728

来源: mdpi

【 摘 要 】

This paper presents a low-cost low-power CMOS humidity sensor for passive RFID sensing applications. The humidity sensing element is implemented in standard CMOS technology without any further post-processing, which results in low fabrication costs. The interface of this humidity sensor employs a PLL-based architecture transferring sensor signal processing from the voltage domain to the frequency domain. Therefore this architecture allows the use of a fully digital circuit, which can operate on ultra-low supply voltage and thus achieves low-power consumption. The proposed humidity sensor has been fabricated in the TSMC 0.18 μm CMOS process. The measurements show this humidity sensor exhibits excellent linearity and stability within the relative humidity range. The sensor interface circuit consumes only 1.05 μW at 0.5 V supply voltage and reduces it at least by an order of magnitude compared to previous designs.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.