Numerical simulation and analysis of passive intermodulation caused by multipaction

In this paper, emphasis is put on passive intermodulation (PIM) caused by multipaction. The results are calculated by particle-in-cell simulation under the conditions of 2-tone and 4-tone carriers. A temporal evolution of the number of particles with different carrier powers is presented. The input and output signals in the time domain and the power spectrum densities of these signals in the frequency domain under different conditions are compared. The relationship between multipaction and PIM interference is discussed. It shows that the appearance of the PIM phenomenon follows the occurrence of saturation of multipactor discharge and the powers of PIM products basically increase as the carrier powers grow. In addition, to suppress the occurrence of PIM interference, an external magnetic field is added in the direction perpendicular to the electric field, which is a practical way to inhibit multipaction, and the effectiveness and the reliability of this method are also verified by simulation.