Title :
Quartz sensor for dielectric measurement in glass-fiber resins
Author :
Matko, V. ; Koprivnikar, J.
Author_Institution :
Fac. of Electr. Eng. & Comput. Sci., Maribor Univ., Slovenia
Abstract :
The dielectric sensor using the sensitive capacitive-dependent crystal is described. In addition, the new idea of excitation of the entire dielectric sensor with stochastic test signals and the dielectric surface-measuring method are given. It includes the influence of test signals on the weighting function uncertainty and on the A/D-D/A conversion. The results of the water absorption measurement in glass-fiber resins are shown experimentally. The uncertainty of the surface dielectric measurement is less than 0.2% (T=15-25/spl deg/C).
Keywords :
capacitance measurement; capacitive sensors; crystal oscillators; glass fibre reinforced plastics; moisture measurement; permittivity measurement; sorption; 15 to 25 C; A/D-D/A conversion; SiO/sub 2/; cross-correlation function; dielectric measurement; dielectric sensor; dielectric surface-measuring method; direct digital method; glass-fiber resins; high sensitivity; open capacitor; quartz oscillators; quartz sensor; relative permittivity; sensitive capacitive-dependent crystal; stochastic test signals; test signals influence; water absorption measurement; weighting function uncertainty; Absorption; Capacitive sensors; Dielectric measurements; Noise measurement; Pulse width modulation; Resins; Sensor phenomena and characterization; Temperature; Testing; Time measurement;
Conference_Titel :
Precision Electromagnetic Measurements Digest, 1998 Conference on
Conference_Location :
Washington, DC, USA
Print_ISBN :
0-7803-5018-9
DOI :
10.1109/CPEM.1998.700016
