The method of extracting impedance parameters of surface mounted (SMD) electronic components by test is suitable for components with unknown model or material information, but requires consideration of errors caused by non-coaxial and measurement fixtures. In this paper, a fixture for impedance measurement is designed according to the characteristics of passive devices, and the fixture de-embedding method is used to eliminate errors and improve the test accuracy. The method of obtaining S parameters of fixture based on full wave simulation proposed in this paper can provide a thought for obtaining S parameters in de-embedding. Taking a certain patch capacitor as an example, the S parameters for de-embedding were obtained using methods based on full wave simulation, 2×Thru, and ADS simulation, and de-embedding tests were conducted. The results indicate that obtaining the S parameter of the testing fixture based on full wave simulation and conducting de-embedding testing compared to ADS simulation can accurately extract the impedance parameters of SMD electronic components, which provides a reference for the study of electromagnetic interference (EMI) coupling mechanism.

LCD Automatic Vision Inspection (AVI) systems automatically detect defect features and measure their sizes via camera vision. AVI systems usually report different measurements on the same defect with some variations on position or rotation mainly because we get different images. This is caused by possible variations in the image acquisition process including optical factors, non-uniform illumination, random noise, and so on. For this reason, conventional area based defect measuring method has some problems in terms of robustness and consistency. In this paper, we propose a new defect size measuring method to overcome these problems. We utilize volume information which is completely ignored in the area based conventional defect measuring method. We choose a bell shape as a defect model for experiment. The results show that our proposed method dramatically improves robustness of defect size measurement. Given proper modeling, the proposed volume based measuring method can be applied to various types of defect for better robustness and consistency.