Filter design using electromagnetic band gap in microstrip reference plane for packaging applications

In the current trend of technologic products is light, small and high-speed, so electronic products widely applied in high frequency. Due to high frequency, the parasitic effects and more noise are generated. To solve this problem, we used to add the band-pass filters behind the signal line to enhance signal integrity (SI) and reduce noise. But this method required to increase size of the circuit. In this study, microstrip is reference plane, a novel EBG structure enable the microstrip become bandpass filter. This new structure is still a transmission line. A section of transmission line embeded EBG in the bottom of transmission lines.EBG combine with ground plane of transmission lines to enable the signal which is not in the pass band will not have return path. The section of microstrip which combine with EBG possess band-pass filter characteristics. The purposes not only reduce the area effectively, but also decrease the cost. This study designs a 4GHz and 2.4GHz bandpass filter structure. The feature in this specifications correspond with provisions of the current range of wireless communication frequency (2.4GHz), and broadcasting TV (4GHz), and in the future there will be more application development.