General And Effective Sampling Strategy And Clutter Filtering Strategy For Quiet Zone In Tri-Reflector Compact Range

As one of the most important unit in the terahertz system, antenna plays a very important role in the setup of terahertz measuring system. Compact antenna test range (CATR) is an advanced technique for millimeter and sub-millimeter wave antenna test which combining advantages of near field test and far field test based on physical optics and geometrical optics. Tri-reflector compact antenna test range is a promising method for electrically large antenna measurement due to that it can generate a pseudo-plane wave region, which is often referred to as quite zone.Now BUPT-QMUL laboratory has designed a tri-reflector CATR system, which works from100GHz to500GHz. In the previous system simulation work, the feed in the system is assumed as ideal Gaussian feed without cross-polarization and other factors that have profound impact on the performance of the tri-reflector CATR. Thus the aim of this paper is to provide a effective and general sampling method to measure the quiet zone performance. Besides, a filtering strategy is proposed to diminish quiet zone clutter noise in quiet zone.The quiet zone performance of terahertz tri-reflector CATR is evaluated by an efficient sampling strategy with rectilinear plane scanning. The method relies on the non-redundant sampling expression of the scattered fields, the theory of digital signal processing and the optimal sampling interpolation method. Numerical results show that the performance of quiet zone can be evaluated by a remarkably reduced number of sampling points. Besides, a brief and general method to deduce clutter noise of a CATR quiet zone is proposed. Results show that quiet zone performance can be greatly enhanced by the proposed clutter noise filtering strategy.