Journal
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
Volume 65, Issue 3, Pages 694-702Publisher
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
DOI: 10.1109/TIM.2015.2506302
Keywords
Capacitive sensor; metal-oxide; relative humidity (RH); response characteristics; signal frequency; sol-gel method
Funding
- Department of Science and Technology, New Delhi, India [SR/S2/CMP-011/2011]
Ask authors/readers for more resources
Efforts have been made by the researchers to enhance the sensitivity of a humidity sensor by selecting and fabricating different nanostructures thin films and optimizing their pore morphology. However, other characteristics, such as nonlinearity, hysteresis, reproducibility, response and recovery times, and selectivity, are equally important for real time measurement, monitoring, and controlling of humidity. It is reported that a low signal frequency is essential for enhanced sensitivity, but the effect of the signal frequency on other characteristics is rarely investigated. We have investigated the role of the signal frequency on the response characteristics of a nanostructure ceramic thin-film interdigitated electrode humidity sensor for the first time. Our studies show that although the sensitivity is high at low frequency, the performance of the sensor is highly nonlinear and frequency dependent. At high frequency above 100 kHz, the sensitivity is reduced, but other characteristics of the sensors are improved significantly. Improved characteristics are due to the reduced effect of double layer capacitance that plays a significant role for extreme sensitivity at low frequency. The effect of double layer capacitance is rarely considered for evaluating the response characteristics in the literatures. Results show that at 200-kHz frequency, nonlinearity and hysteresis are 9.39% and 16.77%, while at 100 Hz, these values are 5588% and 70.8%, respectively. Improve response characteristics will reduce the complexity of signal conditioning, particularly nonlinearity and hysteresis, the compensation of which is essential for almost all types of humidity sensors.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available