Calibration of SAW Based Capacitive Sensor Using Lumped Component and High Precision Gap Measurement

Abstract SAW device is widely used as filters, sensors, actuators in various technologies. And capacitive sensor is tremendously used to measure pressure, gap, etc. The application of SAW device as signal conditioner of capacitive sensor reduces noise level and enables high precision measurement. The response increase of SAW based capacitive sensor is produced just before the two capacitive electrode contacts by the existence of parasitic resistance of capacitive electrode. In this paper, we analyze the effects of parasitic resistance and propose the calibrating method using lumped component and execute the high precision gap measurement using calibrated system. And xx nm resolution and yy m stroke was attained. Key Words : Surface acoustic wave( ), Capacitive sensor( ), Calibration( ), Gap measurement(   ) 1. 서 론 (Surface acoustic wave device, SAW device) Inter digital transducer(IDT),   IDT        ! , IDT,    " # $% &'( )* + , -. , /0 12 345 67% &'8 7 93 ,  " # :;  ?@ A# BC8 DE +# FG H' IB [1]. & J A## H'K  LM& NO BC( ,  P5 QR 6> 8 # ST 6>U & ?@ HV 6>W &'8 XT , / Y P5 A# 5' Z[ \]^ , $_ P2  `ab & ?@ P2 c5 dH ef g8 hi  ?@ 6> _& € 0‚ " xJ P2 Y _ ƒ=„ 5'& o~! [5-8],  $ 6> W † ‡ˆ ‰‚o 5'& o~3 Š‹ , pB Œ BC8 7 yz{ , |} _ ƒ=„ Ž& o~B . t #  :; <= A# *  5' LM% &'( , _0 '‘ A