The simulation results show an improvement of 3.74 dB at 13.28 GHz when using the multi via solution over the standard 1 via per pad solution, as shown in the following figures. The intended use case for this example is a network card running at a data rate of 25 Gb/s. Therefore, the measurement was taken above 12.5 GHz to ensure the result is above the Nyquist frequency.
Figure 1. Red: With GND Vias: –56.17 dB NEXT Between TX and RX
Figure 2. Green: Without GND Vias: –52.43 dB NEXT Between TX and RX
In the following figure, the green line indicates the original cross talk value when using 1 GND via per pad. Without GND vias, it is –52.43 dB NEXT between TX and RX. The red line indicates a new cross talk value when using a multiple GND via solution. With GND vias, it is –56.17 dB NEXT between TX and RX.
Figure 3. S Parameter Plot 1
