Application of Mode Filtering in Near-Field Measurements

This paper briefly introduces the theory of planar near-field measurement and applies cylindrical mode filtering to correct errors in planar near-field measurements. This method decomposes the far-field pattern obtained from planar near-field measurements into cylindrical wave modes. By exploiting the spatial constraint relationship between the cylindrical wave spectrum and the tested antenna, scattering components are filtered out. Finally, the processed far-field pattern is obtained through cylindrical wave spectrum to far-field transformation. By measuring a horn antenna, the algorithmically processed directional pattern is compared with the pattern from simulation software. The results indicate that the algorithm effectively reduces the impact of scattering errors on the far-field pattern.