A Single Chip Integrated Sol-Gel Thin Film LC Sensor for Measuring Moisture in ppm Level

Author

Islam, Tarikul ; Mahboob, Md Rahat ; Khan, Shoab Ahmed ; Kumar, Lalan

Author_Institution

Dept. of Electr. Eng., Jamia Millia Islamia Univ., New Delhi, India

Volume

14

Issue

4

fYear

2014

fDate

Apr-14

Firstpage

1148

Lastpage

1153

Abstract

A simple single chip integrated moisture sensor capable of wireless operation through inductive coupling has been proposed. The structure consists of planar inductor and parallel plate capacitor fabricated by sol-gel thin film of γ-Al₂O₃ (5 μm thick). The sensor chip is capable of measuring ppm level moisture in gaseous environment. The resonance frequency shift of the sensor in the presence of moisture excited by a high frequency ac signal is measured by impedance analyzer (4294A Agilent). The frequency sensitivity of the structure for a moisture range from 100 to 5000 ppm is nearly 119 Hz/ppm. The response and recovery times are 7 and 24 s, respectively. The experimental results show that the output is linear (4.2%), reproducible and stable. Device can be applied for wireless moisture measurement in ppm level.

Keywords

LC circuits; alumina; capacitors; inductors; moisture measurement; sensors; sol-gel processing; 4294A Agilent; Al₂O₃; frequency sensitivity; gaseous environment; high frequency ac signal; impedance analyzer; inductive coupling; parallel plate capacitor; planar inductor; resonance frequency shift; single chip integrated moisture sensor; single chip integrated sol-gel thin film LC sensor; size 5 mum; time 7 s to 24 s; wireless operation; Films; Humidity; Impedance; Moisture; Resonant frequency; Sensors; Wireless sensor networks; $gammahbox{-}{rm Al}_{2}{rm O}_{3}$ thin film; LC sensor; moisture; ppm; sol-gel method;

fLanguage

English

Journal_Title

Sensors Journal, IEEE

Publisher

ieee

ISSN

1530-437X

Type

jour

DOI

10.1109/JSEN.2013.2294336

Filename

6679224