Abstract: A method was presented to mitigate the errors from uncompensated antenna pattern effects in circular near-field monostatic radar measurements. Firstly, a near field signal model was formulated in the presence of an antenna pattern based on the same scattering approximation used in the isotropic situation. Then a modified version of the near field to far field was derived with this model, jumping the traces of multi direction antenna demanded in near field extrapolation. Numerical simulation and experiment results show that the technique can remove antenna pattern errors and improve the accuracy of the far field RCS patterns.