Improved Extrapolation Method With Prior Aperture Phase Distribution

The extrapolation method is widely used to determine the gain of antennas at reduced range distances. A key technique of the conventional extrapolation technique is the use of a full-order polynomial to fit the coupled signals, which inevitably generates redundant terms. In this article, an improved extrapolation method with prior aperture phase distribution is proposed, based on the plane wave expansion theory. By strictly distinguishing the series expansion of different aperture phase distributions, we divide the conventional extrapolation model into an even-order polynomial series model and a full-order polynomial series model. Benefiting from the elimination of redundant terms, full-wave simulation results demonstrate that the proposed method can achieve more accurate gain extrapolation with fewer fitting terms compared with the conventional method. Further experimental validation confirms the strong robustness and effectiveness of the proposed extrapolation technique.