Scattering reduction in spherical near-field measurements

Reflections in antenna test ranges can often be the largest source of measurement errors. This paper will show the results of a new technique developed by NSI to reduce scattering from the walls or other objects in the measurement chamber. The technique, named mathematical absorber reflection suppression (MARS), is a post-processing technique that involves analysis of the measured data and a filtering process to suppress the undesirable scattered signals. The technique is a general technique that can be applied to any spherical near-field test range. It has also been applied to extend the useful frequency range of microwave absorber in an anechoic chamber. The paper will show typical improvements in pattern performance and directivity measurements, and will show validation of the MARS technique by comparing results between a high quality anechoic chamber and a range with limited or no absorber.