| Signal integrity in transmission lines routed above an Electromagnetic Bandgap (EBG) structure is investigated in this thesis. The EBG structure can be designed to induce a wide omni-directional stopband and when it is employed in a conventional parallel plate power distribution network (PDN), efficient suppression of power/ground or simultaneous switching noise is provided. However, the signal lines that are routed above the EBG structure see an interrupted return current path. To investigate this loading effect, a number of signal routing scenarios in a PDN with an embedded mushroom-type EBG structure are investigated through full-wave simulations. Also, a sample prototype based on one of the routing scenarios was fabricated and characterized in frequency and time domain measurements by S-parameters and the output eye diagrams. Furthermore, an equivalent lumped-element circuit is developed to represent the EBG return path. This model is further developed to be applicable to the studied routing scenarios and can be easily incorporated in commercial circuit simulators. The proposed models enable rapid signal integrity analysis as well as global system simulations. Verified by both simulation and measurement results, the signal integrity characteristics of the signal lines backed by an EBG structure are degraded. In order to improve the quality of signal transmission, a modified configuration is introduced. This solution, which utilizes a solid conductor island in the EBG reference plane, offers an optimal insertion loss profile while maintaining noise suppression characteristics of the embedded EBG structure in the PDN. |
