In spherical Near Field (NF) measurements postprocessing techniques based on spatial filtering have been presented as promising tools for the mitigation of echoes or stray signals deriving from the surrounding environment.
The spatial filtering is very efficient in measurement scenarios with a stationary Antenna Under Test (AUT). Whenever the AUT is rotating, in order to increase the effectiveness of the echo reduction, the antenna needs to be displaced outside the center of rotation. Unfortunately, the measurement of the AUT in an offset configuration requires the acquisition of a number of samples higher respect to the onset configuration. An innovative spherical NF/FF transformation algorithm for offset measurements based on a Translated Spherical Wave Expansion (TSWE) has been recently proposed. In this paper, we investigate by experiment the echo reduction properties of offset AUT measurements using TSWE.