1987 Technical Papers

A Low-Cost Spherical Near-Field Range Facility

Authors: John R. Jones, Doren W. Hess, Jr. Curtis E. Green, Ken H. Teegardin
Publication: AMTA 1987
Copyright Owner: NSI-MI Technologies

In any type of electromagnetic measurements, the ideas of "precision and accuracy" and "low cost" tend to be mutually exclusive. At Scientific-Atlanta, for instance, production testing of antenna products is conducted in low cost miniature "anechoic chambers" which are fabricated in-house. These "chambers" are actually mediumsized to large (64-200 cubic feet) rectangular boxes with absorber attached to their walls. They are usually equipped with single axis positioners at one or both ends, and their usefulness is limited to the measurement of axial ratio on low gain small antennas...

Antenna Boresighting

Author: Doren Hess
Publication: AMTA 1987
Copyright Owner: NSI-MI Technologies

The difficulty of discussing the practical aspects of boresighting in general terms has been circumvented by writing two parallel sections - one pertaining to antennas with a fixed mechanical reference and one pertaining to antennas with adjustable optical - mechanical references

The reader is advised to concentrate first on the section that pertains most specifically to his particular antenna boresight problem. Either of Sections I or II may be read without prior knowledge of the other; they are partially repetitive when discussing overlapping material. Those antennas whose boresight reference is defined by touch points on the mounting structure are covered in Section I; those antennas having boresight telescopes are covered in Section II.

Rotated Feed Horns in a Compact Range for RCS Measurements

Authors: Charles Luke, Billy C. Brock, Marion Baggett
Publication: AMTA 1987
Copyright Owner: NSI-MI Technologies

A way has been found to utilize the reflector return in a compact range as a source of continuous drift compensation. This is performed by translating receive polarizations 45 degrees with respect to the transmit polarizations to ensure returns in co- and cross-polarizations. An added benefit is the simplicity of alignment for the polarization calibration standard.