Reflection Suppression in Cylindrical Near-Field Antenna Measurement Systems - Cylindrical MARS
Authors: Stuart Gregson, Allen Newell, Greg Hindman
Reflections in antenna test ranges can often be the largest source of measurement error within the error budget of a given facility. Previously, a technique named Mathematical Absorber Reflection Suppression (MARS) has been used with considerable success in reducing range multi-path effects in spherical near-field antenna measurements. Whilst the technique presented herein is also a general purpose measurement and postprocessing technique; uniquely, this technique is applicable to cylindrical near-field antenna test ranges. Here, the postprocessing involves the analysis of the cylindrical mode spectrum of the measured field data which is then combined with a filtering process to suppress undesirable scattered signals.
This paper provides an introduction to the measurement technique and a description of the novel near-field to farfield transform algorithm before presenting preliminary results of actual range measurements. These results illustrate the success of the technique by showing a circa 10 to 20 dB reduction in spectral reflections (i.e. a reduction in the scattering from a known scatterer within the measurement environment) which is comparable to the degree of improvement attained with the pre-existing, comparable, spherical MARS technique.