Abstract: In a flat flex cable, signal lines are surrounded by logic ground planes above and below which are viaed together left and right. The ground planes coupled with the flex cable dielectric determine characteristic the impedance and attenuation of the cable and provide differential signal EMI shielding. All signal layers and logic ground planes are enclosed within the two outermost shield layers which are viaed together left and right and around the connectors to enclose both signal layers and logic ground planes to provide common mode EMI shielding.

Abstract: A method and apparatus are provided for implementing characteristic impedance discontinuity reduction in customized high-speed flexible circuit applications. A curved artwork region is selected and selected cells are scanned. An area on opposite sides of a signal wire within each cell is determined. The identified areas are compared using a user defined delta value. If the compared areas differ greater than the user defined delta value, then a coordinate change is computed for moving the signal wire to reduce characteristic impedance discontinuity.

Abstract: A method, structure and computer program product are provided for implementing high frequency return current paths within electronic packages. Electronic package physical design data is received for identifying a design layout. For each of a plurality of cells in a grid of a set cell size within the identified design layout, a respective number of signal vias, reference voltage vias, and ground vias are identified. A signal to reference via ratio is calculated for each of the plurality of cells. Each cell having a calculated signal to reference via ratio greater than a target ratio is identified. Vias are selectively added within each of the identified cells for providing high frequency return current paths.