Akademik Veri Yönetim Sistemi
JOURNAL OF ELECTROMAGNETIC WAVES AND APPLICATIONS, cilt.23, ss.999-1010, 2009 (SCI-Expanded)
Microwave calibration-independent methods are promising and attractive for materials characterization since they eliminate any calibration before measurements and hence decrease any error arising from imprecise calibration standards. In the literature, there is a need for simultaneous determination of attenuation constant of wave propagation inside and the length of a line section, which is used effectively in calibration-independent measurements. In this research paper, we propose a simple, yet powerful, procedure for evaluation of these values using measurements of a thru connection and the line connection between error matrices at two different frequencies. It is noted that the accuracy and performance of the evaluation by the proposed procedure increases if longer line and measurements at two widely separated frequencies are selected in the evaluation. We also noted that the performance of measurements may significantly decrease if a line which contains any inhomogeneity throughout its length. In addition, it is important to monitor the repeatability of calibrationindependent measurements to evaluate the accuracy of calibration-independent methods. We have derived a metric function for this evaluation.