Characterization of Dendritic Defects of Polyethylene Insulation Materials Based on Microstrip Gap Resonator

This article attempts to reveal the detection ability of microstrip slot resonator for water and electrical tree defects in insulating samples. The characteristics of microstrip gap resonator are analyzed in high-frequency electromagnetic simulation software. A gap capacitance extraction method is proposed based on two-port transmission theory, and the gap capacitances under different dielectric constants are analyzed based on this method. The resonant frequency of sensor is found to be negatively correlated with the dielectric constant of the materials. In the experimental part, the sensor made of double-sided copper clad plate with medium FR4 was used to detect the water tree and electrical tree in low-density polyethylene (LDPE) samples, and the experiment results showed good feasibility.