Title :
A chemical sensing microsystem utilizing an adaptive feedback circuit
Author :
Fan, X.Z. ; Siwak, N.P. ; Kanakaraju, S. ; Richardson, C. ; Ghodssi, R.
Author_Institution :
Dept. of Electr. & Comput. Eng., Univ. of Maryland, College Park, MD, USA
Abstract :
For the first time, a chemical sensor utilizing optical MEMS with a novel adaptive feedback circuit is presented. This circuit implementation of a hill climbing feedback algorithm is capable of autonomously detecting resonant frequency shifts for a range of MEMS resonators. Eight different cantilever-based sensors (width = 0.6-1.4 mum, length = 40-75 mum, and thickness = 1.8 mum), resonating between 200 kHz to 600 kHz, have been measured. Additionally, the circuit has been used to track resonant frequency shifts due to isopropanol (IPA) adsorption on three different chemical sensors. The frequency detection range, measurement resolution, and sensitivity of the system have been evaluated.
Keywords :
adsorption; cantilevers; chemical sensors; circuit feedback; micro-optomechanical devices; micromechanical resonators; microsensors; MEMS resonator; adaptive feedback circuit; cantilever-based sensor; chemical sensing microsystem; frequency 200 kHz to 600 kHz; hill climbing feedback algorithm; isopropanol adsorption; optical MEMS; resonant frequency shift detection; size 0.6 mum to 1.4 mum; size 1.8 mum; size 40 mum to 75 mum; Adaptive optics; Chemical sensors; Feedback circuits; Length measurement; Micromechanical devices; Optical feedback; Optical resonators; Optical sensors; RLC circuits; Resonant frequency; Feedback circuit; hill climbing algorithm; resonant frequency detection; resonator sensor;
Conference_Titel :
Solid-State Sensors, Actuators and Microsystems Conference, 2009. TRANSDUCERS 2009. International
Conference_Location :
Denver, CO
Print_ISBN :
978-1-4244-4190-7
Electronic_ISBN :
978-1-4244-4193-8
DOI :
10.1109/SENSOR.2009.5285958
