Detection of Passive Intermodulation by Super-Resolution Imaging of Subwavelength Structures

The demand for passive intermodulation (PIM) detection of the base station antennas has increased dramatically. However, when multiple PIM sources are in close proximity, they cannot be located due to the diffraction limit. Subwavelength structures can break the diffraction limit to achieve super-resolution imaging for detecting the multiple close PIM sources. In this paper, we initially investigate the performance of a subwavelength structure made of periodic metal wires to detect the PIM sources based on the super-resolution imaging mechanism by simulations. We analyze the bright spot peak and imaging resolution under different subwavelength structure periods and different positions of the PIM source in the subwavelength structure. Besides, we also find some new phenomena that are different from the traditional analysis of the super-resolution imaging properties of the subwavelength structure made of a metal wire array.