Spatial Filtering in Planar Near Field Antenna Measurement System and Comparison of Two Gain Calculation Approaches

In this study, a planar near field antenna measurement system with 4 m x 1.8 m rectilinear scanning area is introduced for evaluating far-field radiation characteristics and gain of directive antennas which are physically large and heavy. Its initial results are validated by using a standard horn antenna with medium gain at 13 GHz - 18 GHz frequency band. An optimum spatial filter is employed to decrease the error in radiation patterns. In the calculation of gain, two approaches based on pattern integration technique are investigated. Obtained radiation patterns for principal planes and the calculated gains are compared to the reference measurements and the ones provided in data sheet, respectively.