Error Reduction of Absolute Gain Patterns in a Single-Cut Near-Field to Far-Field Transformation

We have proved the equivalence of the Kim method and the Omi method that are promising methods in single-cut near-field far-field transformations in spite of the different appearances [1] . The errors of the absolute gain patterns using those methods come from the deviations of the radiation parts from the center of the rotation in the measurements. In this paper, we propose an improved method to reduce the errors from about 1 dB to below 0.1 dB. In addition, the new method does not need to set the phase center of an antenna under test (AUT) at the center of a measurement turntable: this merit is of great value in real measurements for antennas such as Log-periodic dipole antennas (LPDA), of which phase centers are moving according to the measurement frequencies. The proposed method is based on the new Kim-Omi equation as