Research on Electromagnetic Scattering Characteristics of Transmission Tower With Different Tower Types in Short Wave Band Based on the Characteristic Mode Theory

This research aims to provide a suitable method to analyze high-frequency electromagnetic scattering from extra-high voltage (EHV) transmission line towers with different tower types using characteristic mode theory (CMT). Different from the traditional idea of passive protection based on spatial avoidance, this method combines the existing electromagnetic scattering and CMT with modal decomposition to decompose the total scattering responses of transmission towers into the superposition of characteristic modal responses through mathematical operators and energy relations. The research realizes the correlation analysis between the structural characteristics of transmission towers and the scattering field variation, which provides ideas for the future application of CMT to analyze the electromagnetic scattering from transmission line towers. In this paper, simulation calculations of different types of towers of EHV transmission lines are carried out, and the simulation results are compared and verified with those of the traditional method of moments (MoM). The results show that the tower structure will affect the electromagnetic scattering intensity, and the characteristic current with a larger weight factor will dominate the degree of electromagnetic scattering influence. Compared with the results of the traditional method, the maximum relative error of the simulation results of three different tower structures does not exceed 3%, which verifies the reliability and validity of the method.