The current trend pcb board in the silicon industry toward higher levels of integration generates chips with densities of tens of millions of transistors. As a consequence, the signal switching frequency in modem digital equipment is beyond the gigahertz range. When the bandwidth requirement increases pcb board, the electrical properties of the interconnects affect and limit the integrity of the traveling digital signals. These phenomena also have an impact on the electromagnetic compatibility (EMC) performance of the system since corrupted signals can pcb board easily increase the unwanted electromagnetic interference (EMI).
Until recently, designers performing high-speed PCB simulations were mostly concerned with finding IBIS models for drivers and receivers, but currently the complexity in high speed signals demands additional types of models, not only for IC buffers, but also for packages, vias and connectors. pcb board This is a really challenging task, therefore 3D EM field solvers have to be used in pcb board order to generate touchstone files or equivalent circuit models to be used in, for example, SPICE-based circuit simulators.
The work presented pcb board here was carried out with CST MICROWAVE STUDIO® (CST MWS) and summarises the work by Zianmin Zhang, Kelvin Qiu and Qinghua Bill Chen of Cisco Systems.
The picture illustrates a complex multilayer (26 layers) PCB imported into CST MWS by using the ODB++ file, which was directly generated from the Cadence® Allegro® *.brd file pcb board.
Some discrepancy in the results may be attributed to the measurement set-up. pcb board In this case, a micro-probing technique may be more appropriate. A more reliable TRL calibration would allow the length of the cable to be de-embedded as well as the connectors. Figure 5 shows the proposed measurement pcb board set-up based on these techniques. This study is planned and will be reported in a future article.
Furthermore, pcb board the dielectric properties of the material characterizing the PCB were not provided by the manufacturing company and pcb board a constant value of dielectric loss was assigned within the considered frequency range.
