The ISOFILTERTM Technique: Isolating an Individual Radiator from Spherical Near-Field Data Measured in a Contaminated Environment

Author: Doren W. Hess
Publication: AMTA 2006
Copyright Owner: NSI-MI Technologies

This paper describes a novel method termed the IsofilterTM Technique, of isolating the radiation pattern of an individual radiator from among a composite set of radiators that form a complex radiation distribution. This technique proceeds via three successive steps: A spherical NFFF transform on an over-sampled data set, followed by a change of coordinate system followed in turn by filtering in the domain of the spherical modes to isolate a radiating source. The end result is to yield an approximate pattern of the individual radiator largely uncontaminated by the other competing sources of radiation.

Traditional Antenna Measurements and CTIA OTA Measurements Merging the Technologies

Authors: Donald J. Gray, Ike Lin
Publication: AMTA 2006
Copyright Owner: NSI-MI Technologies

This paper describes traditional antenna measurements and the relationship to the Over-the- Air (OTA) measurements specified by the Cellular Telecommunications & Internet Association (CTIA). It discusses the differences, the likenesses, and the importance of providing a system that can provide both traditional antenna measurements and CTIA OTA measurements. It will address the processes of providing a complete turn-key system – including chamber – that will meet CTIA certifications. Further, this paper shows the unique flexibility and features that the 700S-90 provides for meeting the customer’s needs, for a wide-variety of applications.

Reflection Suppression To Improve Anechoic Chamber Performance

Authors: Greg Hindman, Allen C. Newell
Publication: AMTA 2006
Copyright Owner: NSI-MI Technologies

Reflections in anechoic chambers can limit the performance and can often dominate all other error sources. This paper will show the results of a new technique developed by NSI to suppress reflections and improve performance in anechoic chambers. The technique, named Mathematical Absorber Reflection Suppression (MARS), is a post-processing technique that involves analysis of the measured data and a special filtering process to suppress the undesirable scattered signals. The technique is a general technique that can be applied to any spherical range. It has also been applied to extend the useful frequency range of microwave absorber in a spherical near-field system. The paper will show typical improvements in pattern performance, and will show validation of the MARS technique using data measured on an antenna in a conventional anechoic chamber.


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