Aperture arrays are often designed to provide airflow through shielding walls so that the interior temperature of electronics equipment can be controlled bellow a required level.The electromagnetic energy leakage through the aperture arrays is inevitable

thus the near-field shielding effectiveness must be analyzed when the distance between the radiator and the shielding wall or the distance between two adjacent shielding walls satisfies the near-field condition.In this paper

the FEM for apertures is firstly introduced based on electromagnetic field theory

and the calculation approach of shielding effectiveness by numerical method and the formulation based on the plane wave theory are compared.Then

the effects of some related parameters on near-field shielding effectiveness are analyzed thoroughly.As a result

an approach to improve near-field shielding effectiveness is presented.By the FEM

the shielding effectiveness of aperture arrays with different shapes is analyzed.As the theoretical analysis and simulation results showing

the shielding effectiveness of aperture arrays is greatly overestimated by the classical plane wave theory and the numerical method is more effective in the calculation of near field.The results from numerical simulation shows that the near-field shielding effectiveness can be elevated by reducing the ratio of the size of an aperture to the wave-length of radiator or increasing the number of apertures while the area of apertures keeps unchanged

and three kinds of aperture arrays commonly used in engineering have the similar near-field shielding effectiveness.