Reconstructing Radiation Model of Chip in SiP Based on Magnetic Amplitude from Near-Field Scanning Measurements

With the continuous increase in chip frequency, the internal electromagnetic interference (EMI) of system-in-package (SiP) becomes more prominent. To perform an EMI simulation of a SiP, it is essential first to establish the radiation model of the chip. This article proposes a novel approach using only magnetic amplitude measurements of the near-field for reconstructing the radiation model of the chip within SiP. First, the magnetic field amplitude of the chip within the SiP is measured using near-field scanning technology. Considering that the high dielectric constant of the substrate material significantly influences the magnetic field around the chip, the numerical Green’s function (NGF) is derived on the sampling plane by numerical methods. Then, a magnetic field equation for the reconstruction model is established using the NGF and near-field magnetic field amplitude. And to mitigate the risk of the equation-solving process becoming trapped in local optima caused by the absence of phase information, a hybrid differential evolution algorithm combining simulated annealing with differential evolution is proposed, which conducts local searches within the solution space during the cooling process, to ensure that the result converges to the global optimum. Application examples demonstrate that the proposed reconstruction method can achieve satisfactory accuracy.