Maximum Determinant Sampling Using Spline-Based Trajectories in a Robot-Based mm-Wave Antenna Test Range

Robot-based measurement systems provide new degrees of flexibility in antenna measurement technology. However, in order to exploit the potential of these systems, they should not be used analogously to conventional positioning systems, such as linear axes or roll-over-azimuth positioners. Spline-based measurement paths are one way of exploiting the potentials and, in addition to almost arbitrary measurement paths, also allow more precise trigger signals at the desired sampling points. Furthermore, sampling grids exist which require significantly fewer sampling points for a stable calculation of the far field, such as the maximum determinant sampling grid (MDSG). Since the MDSG cannot be efficiently implemented with conventional positioning systems, it has been of rather theoretical interest. It is shown that robot-based systems allow an efficient implementation of such complex sampling grids. The resulting deviations, depending on the choice of MDSG, show a maximum equivalent error signal of approximately −30dB, shown for frequencies of 60GHz and 90GHz. Compared to a spline-based equiangular reference measurement, the MDSG allows a 25% shorter measurement duration using the same path speed.