IJE TRANSACTIONS B: Applications Vol. 26, No. 11 (November 2013) 1275-1280   

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A. Hassanzadeh, Y. Zou and R. G. Lindquist
( Received: December 31, 2012 – Accepted: February 28, 2013 )

Abstract    In this paper excitation characteristics of the Liquid Crystal (LC) capacitive chemical and biological sensor are examined and the optimum frequency and voltage range for the sensor interface are introduced. Interdigitated capacitor has been used for the sensor capacitance measurement and two different molecular orientations, homeotropic and homogenous, have been considered. The LC sensor capacitance has been measured for different frequencies from 20Hz to 2MHz and voltages from 0/5V to 20V. In both cases, the effects of excitation on the capacitance value and the accuracy of the measurement are investigated. Simulation and experimental results support the proposed range of measurement.


Keywords    Liquid Crystal Capacitive Sensor, Liquid Crystal excitation, Interdigitated Capacitor.


چکیده    در این مقاله مشخصات سیگنال تحریک سنسورهای خازنی برای اشکارسازی مواد بیولوژیکی و شیمیایی مورد بررسی قرار گرفته و فرکانس و ولتاژ بهینه برای تحریک سنسور بدست آمده است. از خازن شانه ای برای اندازه گیری سنسور خازنی در دو ساختار هموژن و هوموتراپیک استفاده شده است. خازن سنسور برای رنج فرکانسی 20هرتز تا 2 مگا هرتز و ولتاژهای 5/0 ولت تا 20 ولت اندازه گیری شده است. در هر دو حالت اثر سیگنال تحریک روی مقدار خازن و دقت اندازه گیری مورد بررسی قرار گرفته اند. نتایج شبیه سازی و اندازه گیری های آزمایشگاهی رنج بهینه سیگنال تحریک بدست آمده را تایید میکند.


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