Dielectric Constant Measurement of Liquids Using Nanosecond-Pulsed Signals

In this paper, we report a novel method to measure the dielectric constant of various liquids of limited amount. The liquid under test is sealed in a coaxial-like test device. The dielectric constant is determined by comparing the delay of a nanosecond-pulsed signal traveling through the test device with that traveling through a reference coaxial cable. The results show that the maximum error of this kind of measurement is within 15-30%, which is good enough for a semi-quantitative estimation of the dielectric constant of an unknown liquid, especially when the amount of the liquid is not enough for investigation with other existing approaches.