Dielectric Constant Measurement System Based on Rapid Switching

The goal of this paper is to develop a dielectric constant measurement system for insulation material of a coaxial cable, implemented via a field-programmable gate array (FPGA). The operation principle is based on the frequency-matched mechanism under rapid switching. Compared to the typical multiline method, this approach completely avoids the need for utilization of a vector network analyzer or a time domain reflectometer, thus eliminating the related calibration issues. It only requires two rapid switches that toggle on/off in opposite time sequences, along with the square signals generated by the FPGA to control the switches. As the measured results for the dielectric constant of the TEFLON material show that the measurement error is approximately around 3%.