De-embedding methods for characterizing PCB interconnections

When the bit rate of the digital signals exchanged between PCBs are in the gigabit per second range, the electrical characteristics of the PCB traces can alter the signal propagation. Consequently, the designer has to evaluate accurately the electrical behavior of PCB interconnects used for transmitting high speed digital signals. Measurements can be carried out on PCB traces usually connected to the measurement instrument using some kind of transition network or fixture (e.g. SMA connectors). To de-embed the effects of these fixtures, so to evaluate the electrical behavior of the only used traces, the paper proposes three simple methods in the frequency domain.