I. Introduction
The intensive passive intermodulation (PIM) interference, which is caused by the passive devices in all the satellite communication systems with large capacity and high power, becomes one of the important factors in the spectrum planning and the equipment performance estimation due to the nonlinear nature of materials and metal contact [1], [2]. The PIM of coaxial cables, connectors, and waveguides has been theoretically and experimentally investigated for many years [3]–[5]. Nevertheless, in terms of the mesh reflector antenna, the relevant research seems to be seldom reported. Due to the complexity of microscopic contact mechanism for metal mesh, the theoretical approach of the PIM modeling of the mesh reflector antenna is still in the infant stage. Summarily, in 2002, Pelosi’s group proposed that the PIM scattering was caused by the nonlinear metallic contact. They also predicted the PIM by applying the time-domain physical optics (TDPO) method to nonlinear space [6], [7]. However, one prominent shortcoming of the TDPO is that the method is not accurate in the calculation of complex microwave components since the incident wave is approximated to a plane wave and the time-domain algorithm have lots of serious accumulated error. In order to address this problem, Liu et al. [8] proposed the collaborative calculation method of PIM on solid reflector antenna consisting of metal plates and gaps based on the frequency-domain simulation and nonlinear circuit.