Evaluation and Correction of Cable Phase Stability in High Frequency Near-Field Measurement

In case of the near-field measurement, the radiated field by the measured antenna is received by two- dimensional scanner in defined points. During the process of the field scanning, the cable between the VNA and the scanner antenna is moved and its parameters are changed. This paper deals with the evaluation of the cable parameters changes. The dominant change is represented by the phase deviation of the cable transmission coefficient. The paper also proposes the method of the cable errors correction and evaluation of the correction method efficiency. The correction can be based on the full calibration at the reference plane of the scanner antenna feeding in all points of scanned field. The aforementioned approach is more time consuming than the proposed method, where the full calibration is performed in one selected point, while the correction of the cable parameters is based on the estimation based on the input impedance of the cable loaded by the scanner antenna.