## 6 Conclusions  
In this paper, the influences of the feed offset error and scanning error on antenna microwave holographic measurement are simulated and analyzed, and compensation methods are proposed. The main conclusions and contributions include the following two parts:  
First, the influence of feed offset error on far-field pattern is analyzed by geometric optics, and the influence mechanism of feed offset error on antenna gain and surface shape measurement error is established. Through simulation analysis, the relationship between feed offset error and antenna gain loss is quadratic. The greater the feed offset error, the more serious the antenna gain loss, and the smaller the antenna focal diameter ratio, the greater the influence of the feed offset error on the antenna gain loss. There is a linear relationship between the feed offset error and the RMS of the surface measurement error. The larger the feed offset error, the larger the RMS of the surface measurement error caused by the feed offset error, which leads to a decrease in measurement accuracy. The smaller the antenna focal diameter ratio, the greater the influence of the feed offset error on the RMS of the surface measurement error. Finally, the actual offset of the feed is solved by using the phase distribution of the aperture field with the feed offset error, and the actual feed offset obtained by the inverse solution is used to compensate the surface measurement results, which basically eliminates the influence of the feed offset error. Secondly, the scanning error of the antenna during the scanning process is simulated by changing the coordinates of the far-field sampling points. Due to the randomness of the scanning error, it is difficult to directly perform quantitative analysis like the feed offset error. The influence of scanning error on antenna gain loss and surface shape measurement accuracy can only be studied by probability statistics. Through research, it was found that although the scanning error is very small in the actual measurement process, it will also affect the measurement results, reduce the antenna efficiency, and reduce the measurement accuracy. Finally, a compensation method to reduce the influence of scanning error is provided, and the feasibility of the method is verified by simulation cases. By comparing the results of surface shape measurement error before and after compensation, the influence of scanning error on surface shape measurement accuracy is effectively reduced. Finally, in the actual scanning process of the antenna, there are many factors, such as feed offset error, misalignment of feed phase center and focus, pointing error, noise error, scanning error, and so on. This paper only analyzes the influence of feed offset error and scanning error, and the error influencing factors are not comprehensive enough. Future research should consider more comprehensive error sources, adopt more comprehensive error analysis methods, and consider more influencing factors, which will be the key to improving the accuracy of antenna performance evaluation and system optimization. Conceptualization, formal analysis, B.X. and Y.Z. ([PERSON]); methodology, B.X., S.L. and Y.Z. ([PERSON]); software, data curation, writing--original draft preparation, Y.Z. ([PERSON]); investigation, Y.Z. ([PERSON]) and W.W.; project administration, funding acquisition, B.X. ; All authors have read and agreed to the published version of the manuscript. This research was funded by the Natural Science Foundation of Xinjiang Uygur Autonomous Region (No. 2023D01C22), the National Natural Science Foundation of China (No. 12363011, 52275270, 52275269), the Tianchi Talents Program of Xinjiang, the National Key Basic Research Program of China (No. 2021 YFC2203501) and the Xinjiang Postdoctoral Foundation. Not applicable.