Effect of Different Shapes on the Measurement of Dielectric Constants of Low-Loss Materials With Rectangular Waveguides at X-Band

To quantify the effect of air gap on the dielectric constant measurement of low-loss materials, this letter presents the first quantitative study of the effect of five different shapes on the dielectric constant measurement using three low-loss materials as examples. The experimental results show that if low-loss materials' dielectric constant measurement error is controlled within 5%, the air gap cannot exceed 4%. The results of this letter can provide effective guidance and reference for improving the measurement accuracy of electromagnetic parameters of low-loss materials.