Title :
SNR improvement in MEMS electrothermal displacement sensors
Author :
Mohammadi, Arash ; Moheimani, S.O.R. ; Yuce, Mehmet Rasit
Author_Institution :
Sch. of Electr. Eng. & Comput. Sci., Univ. of Newcastle, Callaghan, NSW, Australia
Abstract :
Electrothermal displacement sensors are doped silicon resistors used for nanopositioning purposes. The displacement precision of the nanopositioners is strongly dependent on the signal to noise ratio (SNR) of the sensors. The sensitivity of the electrothermal sensor is proportional to the temperature of the sensor. However, higher temperature increases the thermal noise of the device. We propose new methods both in the device and the readout circuit to improve the SNR. The design of a multiple sensor architecture is reported in this work. Through experiments we show that with averaging multiple sensor signals the overall SNR is improved by the number of averaged sensor outputs. The experiments are carried out on SOI (Silicon on Insulator) MEMS (Microelectromechanical Systems) nanopositioners. By combining three sensor outputs, we achieved a 4 dB enhancement in SNR. Furthermore, the sensitivity of commonly used Wheatstone bridge and transimpedance amplifier (TA) readout circuits are investigated. We show analytically and experimentally that TA circuit offers four times higher sensitivity.
Keywords :
bridge circuits; displacement measurement; elemental semiconductors; microsensors; nanopositioning; nanosensors; operational amplifiers; readout electronics; resistors; sensor fusion; silicon; silicon-on-insulator; thermal noise; MEMS electrothermal displacement sensor; SNR; SOI; Si; TA; Wheatstone bridge; microelectromechanical system; multiple sensor architecture; nanopositioning purpose; noise figure 4 dB; readout circuit; signal to noise ratio; silicon on insulator; silicon resistor; thermal noise; transimpedance amplifier; Bridge circuits; Nanopositioning; Sensitivity; Signal to noise ratio; Temperature sensors;
Conference_Titel :
Advanced Intelligent Mechatronics (AIM), 2014 IEEE/ASME International Conference on
Conference_Location :
Besacon
DOI :
10.1109/AIM.2014.6878138