W-band characterization of dielectric constant and loss tangent based on substrate integrated non-radiating dielectric guide resonator method

This paper introduces a feasible method to accurately measure the dielectric constant and loss tangent of printed circuit boards based on the substrate integrated non-radiating dielectric (SINRD) cavity at 90 GHz. The SINRD cavity operates in LSM₁₂₀ mode with low conductor loss. A tested material with high dielectric constant makes the SINRD cavity having low radiation loss. In this case, the overall loss is primarily determined by the dielectric loss, thus the measured dielectric parameters are accurate. The dielectric constant can be determined by the resonant frequency. Then, a simple method is proposed to evaluate the loss tangent.