Development of a Motion-Capable Model for a Robot-Based Antenna Measurement System to Simulate Scattering-Induced Interference

An antenna measurement system at the Institute of High Frequency Technology at RWTH Aachen University is being established containing a six-axis robot arm allowing the realization of numerous measurement geometries. Room scattering is one of the most crucial uncertainty terms in every antenna measurement which becomes even more interesting in a dynamic scattering situation. To determine the scattering-induced interference caused by the robot, a motion-capable model is developed and firstly simulated using the multi-level fast multipole method between 8 GHz and 12 GHz to qualitatively assess the surface currents. Secondly, asymptotic simulations are carried out using physical optics for the most important robot positions at 60 GHz which is in the frequency range where the system is operated. For example, differences in the same simulation points of up to 20 dB are shown for different robot positions. Based on the simulation results, the measurement sequences can be optimized by selecting a trajectory which reduces the scattering effects. In addition, the strongest scattering sources of the robot are identified in order to cover these parts by absorbers. Therefore, the knowledge gained from the simulations can be applied to the measurement system to improve the performance of antenna measurements.