Abstract
This research focus on the mythology of material characterization at microwave frequency. According to shape and properties of material, different approach is required. There are two parts in this research. The first part of this research concentrates on the mythology of complex permittivity and permeability measurement of a bulk material based on transmission/reflection method. A new algorithm known as Two Steps Parameter Fitting algorithm and well-defined experimental process were developed. Through the new algorithm, the algebraic instability caused by resonant transmission is successfully suppressed. And the effect of conducting loss was also taken into consideration. By the means of well-defined experimental process, the error of misalignment and other unwanted effect were averaged out. The complex permittivity and permeability of Teflon and Al2O3 were measured in Ka band. The fluctuation and standard deviation of complex permittivity and permeability derived by new method is at least ten times smaller than that derived by conventional method. The first part of this research focuses on mythology of complex permittivity measurement for thick film. Theoretically, a cavity / cavity perturbation mixing method was proposed. And the important concept of time domain analysis of close cavity was clarified. Based on this concept, the capability of measuring the dielectric loss tangent of film was realized. Experimentally, a high sensitivity cavity measuring system was designed and fabricated. The effect of film is emphasized by the high Q cavity. And a set of well-defined experimental procedures is proposed as well as followed. Eventually, the complex permittivity of 11μm thick SU-8 2050 coated on quartz substrate was measured. Its real part of relative permittivity is 3.33 which is consistent with the provided datasheet. And its imaginary part of relative permittivity is 0.08.