Analysis of excitation frequency to performance of electrical capacitance tomography

Electrical capacitance tomography (ECT) is one of imaging technique based on permittivity distribution of object inside the sensor. The principle of ECT is injection of square or sine wave signal with a certain frequency. In this paper, excitation frequencies of ECT system are analyzed in term of accuracy and system's performance. The frequency excitation will be scanned from 10 to 1500 kHz with 10 kHz of increment, hence the impedance value of ECT system can be obtained. Experiments using cylinder rods were conducted to validate the result of image reconstruction against excitation frequency. The good performance is in the frequency of 170–1000 kHz, which is the area at smaller impedance.