Accuracy Improvement in Calibration Method for Complex Material Characterization by Coaxial Holder

In recent years, absorber coatings are extensively-used for electromagnetic interference (EMI) shielding in high-speed circuits. Therefore, it is crucial to characterize the complex electromagnetic properties of these absorber coatings. In this paper, an improved calibration method is proposed for broadband material characterization. Even though samples under test (SUT) are measured using non-ideal cascaded flanged coaxial holders, an improved calibration procedure and a criterion are proposed to enhance the calibration accuracy. Then, the reflection/transmission (T/R) method is employed for extracting the complex electromagnetic properties. To validate the accuracy of material characterization, the proposed calibration method is applied to two samples, including an acrylic sample and a commercial absorber sample. Great agreements between the datasheets and the extracted properties with the proposed method have been shown.