Tan delta measurement of paper insulated laminates using capacitance method from 300kHz to 50MHz

Tan delta measurement of oil impregnated kraft paper extracted from paper insulated lead covered cables (PILC) has been performed using a parallel plate capacitor and a vector network analyzer (VNA) from 30 kHz to 50 MHz. The material under test (MUT) is flat and thin sample clamped between the capacitor plates and connected to the VNA to obtain its two port S parameters. The S parameter is converted into impedance to calculate the complex permittivity using Matlab program. Techniques used to overcome the air gap and stray capacitance was described. Measurement obtained using the proposed method was compared with the free space method to validate its accuracy. The percent difference is less than 5%.