Research On Spherical Near-Field Fast Measurement Technology Based On Interpolation Method

With the rapid development of 5G technology and 6G technology,there is a growing demand for high-performance antennas,leading to increased requirements for antenna measurement techniques.However,due to the influence of measurement distance and electromagnetic environment,far-field measurement techniques are unable to meet the measurement requirements of complex structures and large-scale antennas.Therefore,near-field measurement techniques have garnered extensive attention from researchers.Among these,spherical near-field measurement technology is the most accurate method for antenna near-field measurements.This thesis is based on the theory of spherical mode expansion and primarily focuses primarily on the issues of measurement errors and efficiency in spherical near-field measurement.It proposes a fast measurement scheme for spherical near-field based on the interpolation concept.The main content of this thesis includes the following three aspects:1.To address the issue of measurement errors caused by unexpected missing near-field antenna data,a machine learning-based interpolation method for near-field data is proposed.Through simulation validation,it is demonstrated that the interpolated near-field dataset,when subjected to spherical near-field to far-field transformation,can accurately reconstruct the far-field radiation pattern of the antenna,thereby avoiding the need for re-measurement and reducing measurement time costs.2.Based on the iterative optimization concept,a spherical phaseless near-field to far-field transformation algorithm is proposed and its effectiveness is validated through simulations.By analyzing the impact of different double-sampling spherical distances and sampling intervals on the transformation results,it is concluded that the double-sampling spherical distance should be greater than 10 times the wavelength and that a smaller sampling interval should be used to ensure measurement accuracy.3.To address the issue of decreased accuracy in spherical phaseless near-field to far-field transformation due to increased sampling intervals,a 2D interpolation method is proposed to interpolate and complete the missing near-field magnitude data in the azimuth and elevation directions.Through simulation validation,it is demonstrated that the proposed method can achieve higher accuracy in the transformation results using only 25%of the original sampling strategy’s near-field data.