关键词: 信号完整性, 阻抗失配, 散射参数, 时域, 仿真

Abstract: For the signal integrity problems caused by reflection in high speed signal design, the mathematical expression of scattering parameters on impedance distribution in a single network is derived, and the influence of impedance mismatch degree and distribution length on return loss in transmission structure is clarified. Based on this expression, the difference of reflection calculation between frequency domain and time domain is further discussed. Combining common frequency domain phenomena and simulation predictions, it explains the causes of high frequency deterioration of return loss and asymmetric return loss, and proposes some unconventional methods for impedance design in specific frequency range, thus providing an in-depth understanding of impedance matching for those who are new to the field of signal integrity design.

Key words: signal integrity, impedance mismatch, scattering parameter, time domain, simulation