Abstract: In order to extract channel characteristics in specialized 5G application scenarios and reduce the deviations in simulation results under aperture-coupled models produced by ray tracing (RT) methods, this paper proposes a novel method for extracting channel features in wireless communication scenarios involving minuscule apertures. A metallic cavity model with dimensions of 100 mm×100 mm×15 mm is established, and through simulation, the differences in field strength distribution extracted by the full wave method and ray tracing method are compared. Based on the ray tracing and utilizing convolution operations, we propose a new method for field strength extraction that more closely aligns with actual field distribution characteristics. The channel modeling method and field strength extraction method proposed in this study provide a new theoretical basis for the propagation of electromagnetic waves in specific enclosed scenarios. This method improves simulation efficiency compared to the full wave method and enhances simulation accuracy compared to the ray tracing method when dealing with enclosed mental scenarios that include apertures.