Calibration approaches in Multi-Node Antenna Characterization Setups

In this work we present calibration approaches aimed at mitigating the measurement error in testbenches featuring multiple sensor-nodes and operating over-the-air. Such errors can arise from fluctuations in component responses and mechanical tolerances of the setup. The calibration approaches are detailed for the case of the Antenna Dome measurement setup previously presented by the authors.In the current implementation, the Antenna Dome employs multiple dual linearly-polarized scalar sensing nodes, to enable real-time 2D (theta and phi) radiation pattern acquisition. The variation of the electrical response among the different sensing elements as well as their position, with respect to the nominal one, due to the mechanical tolerances, introduce systematic error in the generated radiation patterns.Over-the-air procedures to linearize the power conversion asymmetry within the dually polarized nodes as well as the linearity response across them are described. Proposed approach provides a reduction of the angular dependent error within ±0.5 dB across the various nodes. Moreover, to minimize the impact of mechanical deviations an over-the-air method is described to transfer the sensor coordinates from the mechanical reference system to the antenna under test one.