Comparisons of microwave dielectric property measurements by transmission/reflection techniques and resonance techniques

This review provides a general comparison of the two most commonly used techniques for measurement of complex permittivity at microwave frequencies: transmission/reflection and resonance. The transmission/reflectance techniques are analyzed using distributed and lumped impedance models. The resonance techniques are analyzed using both dielectric and cavity resonance models. The analysis, combined with experimental results, enables us to illustrate the advantages and disadvantages of the various techniques and provide guidance on which techniques to use under particular circumstances. In general, transmission/reflection techniques can be used over a broad band of frequencies, and are suitable for loss measurements on high loss materials. Resonance techniques do not have swept frequency capability, but have higher accuracy for measurement of the real part of permittivity and can measure the loss tangent of low loss materials with high resolution.