Gain Antenna Measurement using Single Cut Near Field Measurements

Technical Publications
Tuesday, November 29, 2016

This  paper  presents  a  near-field  antenna  test procedure providing  single  or  double  main plane  patterns  including  the gain.  The procedure  is  applicable  to  antennas,  with separable excitation in the two main planes. The test set-up is based on an azimuth positioner and near to far-field transformation based on expansion in cylindrical modes. The paper shows results for gain measurements. Near to  far-field transformation  is  performed using  the cylindrical  modes  expansion  assuming  a  zero-height cylinder. This allows the use of a FFT in the calculation of the far field pattern including probe correction. In the case of gain, the near to far-field transformation factor is calculated for bore sight direction, taking advantage of the separable excitation properties of  the  antenna. This  factor  is  used in  the  gain  calculation by comparison technique.