Sampling Effect on Radiation Characteristics of Automotive 5G Antenna in Spherical-Near-Field Test Range

Since integrated antennas are strongly coupled with the vehicle body structures, antenna measurements on vehicle level are necessary to accurately characterize the antenna performance. Due to large Fraunhofer regions of typical vehicles, especially at higher frequencies for mobile communications, near field measurement ranges are in many cases implemented. This contribution addresses a sampling requirement issue during the spherical near field measurement of automobile integrated antennas. The measurement results demonstrate a significant deviation on measured radiation patterns and total radiated power (TRP) value of an integrated automobile antenna by using 1 degrees and 10 degrees sampling step in spherical near field measurements. Therefore, a sufficiently fine sampling step is necessary to guarantee a correct measurement results of radiation characteristics in spherical near field test range. In this paper a 5G antenna integrated on vehicle roof is taken as an example, but note that the phenomenon mentioned here is not limited to a specific antenna type.