Shielding effectiveness analysis of an infinite cylindrical structure with a lateral aperture by modal method of moments

In this study, an efficient and exact numerical technique based on modal method of moments (MoM) is presented to evaluate shielding effectiveness of an infinite cylindrical enclosure with a lateral aperture on its wall. To this end, modal vector wave functions are used to represent the electric field and consequently the surface magnetic current on the aperture. To calculate inside and outside magnetic fields, the circular waveguide dyadic Green's functions are utilised. The unknown magnetic current on the aperture is calculated using the MoM by enforcing the continuity of tangential magnetic field on the aperture. This method is employed for different enclosure sizes when illuminated by transverse magnetic (TM) polarised wave at two different incident angles.