Electrical characterisation of high-frequency thickness-shear-mode resonators by impedance analysis

Citation
B. Zimmermann et al., Electrical characterisation of high-frequency thickness-shear-mode resonators by impedance analysis, SENS ACTU-B, 76(1-3), 2001, pp. 47-57
Citations number
27
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Spectroscopy /Instrumentation/Analytical Sciences","Instrumentation & Measurement
Journal title
SENSORS AND ACTUATORS B-CHEMICAL
ISSN journal
0925-4005 → ACNP
Volume
76
Issue
1-3
Year of publication
2001
Pages
47 - 57
Database
ISI
SICI code
0925-4005(20010601)76:1-3<47:ECOHTR>2.0.ZU;2-G
Abstract
Increasing the frequency of coated AT-cut quartz resonators should result i n an increase of the measuring signal of these devices in the application a s chemical sensors. A combined photolithographic/etching process allows a r eliable fabrication of mechanically stable resonators with frequencies up t o 75 MHz. The results of the electrical characterisation of the high-freque ncy resonators by means of impedance analysis are presented. The measured e -values are about 5 x 10(4), which is an excellent figure for high-frequenc y resonators. The separation of unwanted inharmonic from harmonic modes is improved by reducing the diameters of the deposited electrodes. The depende nce of the equivalent circuit values on frequency and electrode diameters a re investigated. The results reveal good agreement with theoretical values obtained from a one-dimensional transmission-line model for L and C-1 and q uite poor agreement in R and C-0. Investigations on the impedance behaviour under liquid load show an increase in damping for high-frequency resonator s as expected. The possibility for operating the high-frequency resonators in an oscillator circuit under liquid load depends on various influence par ameters. A general estimation is difficult to be made and should be tested experimentally for certain applications. However, the use of resonators wit h frequencies higher than 50 MHz in liquids seems not to be advisable. (C) 2001 Elsevier Science B.V. All rights reserved.