Experimental Extraction Method for Primary and Secondary Parameters of Shielded-Flexible Printed Circuits

In recent years, the development of electronic devices are trending to be smaller and lighter, the techniques for suppressing electromagnetic (EM) radiation need to comply with these trends. EM shields are widely used to suppress EM radiation from transmission lines. EM shield for interconnection cable such as flexible-printed-circuits (FPC) requires flexibility of shielding-material. Consequently, EM shield becomes much more thin metallic shield and may be implemented near the transmission lines in the future. However, frequency response of the transmission coefficients of the shielded-FPC has dispersion due to insufficient shielding performance for near magnetic field. Elucidating the relationship between dispersion of frequency response and time response of transmission characteristics of shielded-FPC turns to be an important indicator of shielding techniques. In this paper, experimental extraction has been proposed for detailed investigating the frequency dispersion of shielded-FPC by using the RLGC equivalent-circuit model. The experimental extraction method used S-parameters measured by using vector network analyzer. The unnecessary components such as connectors are compensated correctly by using proposed method. The frequency response of primary and secondary parameters extracted using the proposed method reproduces all the dispersion characteristics of shielded-FPC successfully. More importantly, quantitative evaluation using the RLGC equivalent-circuit model considering dispersion characteristics can be performed experimentally.