Dielectric measurements on substrate materials at microwave frequencies using a cavity perturbation technique

A cavity perturbation resonance technique suitable for microwave measurements on substrate materials is discussed. The technique makes use of thin rectangular samples placed in a rectangular waveguide cavity (Q∼5000). The availability of advanced microwave measurement equipment makes it possible to record experimental data at several frequencies (five in this present case). The estimated accuracy of measurements is ±2% for dielectric constant and 3×10^-4 for dielectric loss. Results are reported in the 8.2-12.4-GHz frequency range for alumina and specially prepared silica.