As System-on-Chip (SoC) has become more pervasive in recent years, the substrate noise coupling problem has become an increasing challenge in mixed-signal IC design. This book provides a thorough understanding of substrate noise generation mechanisms, 3D substrate modeling, and substrate noise suppression techniques. Furthermore, an active noise suppression technique, developed by the author, is presented in detail, including the theory analysis, 3D substrate and isolation structures modeling, simulation methodology, test site design, and data analysis. At the end, an insightful discussion is provided, helping readers comprehend the advantage, limit, and possible improvement of the technique. This comprehensive book serves as a manual of substrate noise, helping understand substrate noise and helping choose/create effective noise suppression techniques, for RF/mixed signal IC designs.