[show abstract][hide abstract] ABSTRACT: The electromagnetic compatibility simulation of the power delivery network inside the integrated circuit packaging becomes an important issue in the modern circuit design. In this paper, this complex power-ground plane is divided into the internal region and external region. These two regions are simulated by using the hybrid integral equations. The internal integral equation is described by using the rectangular cavity dyadic green functions, while the external integral equation is described by using the free-space green function. These two equations are coupled through the equivalent magnetic current placed on the periphery and gaps of the power-ground plane. This proposed method could accurately simulate both the coupling between vias inside the power-ground plane and the emission from the periphery and gaps of the power-ground plane. Through several examples, its accuracy and efficiency are validated.