Signal intergrity analysis for SMA via on the PCB

SMA connector is widely used in the high-speed interconnection system. As more designs move toward high-speed serial links with picosecond edge rate, the signal integrity problems caused by the transition structure from SMA connector to the PCB cannot be neglected, especially for precise AFR calibration. To solve this problem, we present four optimization methods, including optimizing the size of anti-pad, back-drilling, adding GND vias around the signal vias and providing a diving board, which are investigated by HFSS. Finally, by testing two different commonly-used SMA connectors, we can see that the bandwidth after optimization is at least twice as high as that before the optimization. This effectively overcomes the signal effective bandwidth limitations brought by discontinuous impedance and ensures the accuracy of high-speed link verification.