1999 Technical Papers

The Effect Of Measurement Geometry On Alignment Errors In Spherical Near-Field Measurements

Authors: Allen C. Newell, Greg Hindman
Publication: AMTA 1999
Copyright Owner: NSI-MI Technologies

Papers were presented at the last two AMTA meetings reporting on the effect of rotator system alignment on the results of spherical near-field measurements. When quantifying the effect of non-intersection errors on the AUT directivity, these two papers presented very different results. One AMTA paper1 and an earlier study at The Technical University of Denmark2 found that the directivity error was extremely sensitive to non-intersection errors while the other AMTA paper3 found a very small sensitivity. During the past year, scientists at the Technical University of Denmark, The National Institute of Standards and Technology, and Nearfield Systems Inc. have been working together to determine the reasons for these differences. It now appears that the major reason for the difference is due to the method used to acquire data on the sphere. Theta scans that pass through the pole, or equivalently, phi spans of 180 degrees, produce both plus and minus phase errors that tend to cancel in the on-axis direction. Theta scans that do not pass through the pole, or equivalently phi spans of 360 degrees, produce phase errors of the same sign over the sphere which are concentrated in the on-axis direction. Examples of measurements and recommendations for using this information in spherical measurements will be presented.

 

Atlanta

1125 Satellite Blvd. NW,
Ste. 100
Suwanee, GA 30024 USA

+1 678 475 8300
+1 678 542 2601

Los Angeles

19730 Magellan Dr.
Torrance, CA 90502 USA

+1 310 525 7000
+1 310 525 7100

NSI-MI UK

C/O AMETEK LAND,
Stubley Lane,
Dronfield, S18 1DJ UK

+44 1246 581500

Space-Comm Expo

Farnborough, UK Finding your local time... 9 Days www.space-comm.co.uk
This site is using cookies for analytical purposes and to provide a better user experience. Read our Privacy Policy for more information.