NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Case study of sample spacing in planar near-field measurement of high gain antennasFar field antenna patterns can be reconstructed from planar near field measurements acquired at a sample spacing of lambda/2 or less. For electrically large antennas, sampling at the Nyquist rate may result in errors due to system electronic drift over long acquisition times. The computer capacity may limit the largest size of the near field data set. The requirement to sample at the Nyquist rate is relaxed for high gain antennas which concentrate most of the radiated energy into a small angular region of the far field. The criteria for sample spacing at greater than lambda/e through the use of a priori information of the antenna radiation characteristics are presented. Far field patterns of a 30 GHz dual offset reflector system with a 2.7 m parabolic main reflector are computed from near field data obtained at sample spacings ranging from 0.1 lambda to 10 lambda. The effects of sampling interval and spectrum cutoff on the far field patterns are discussed.
Document ID
19850001927
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Acosta, R. J.
(NASA Lewis Research Center Cleveland, OH, United States)
Lee, R. Q.
(NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
September 5, 2013
Publication Date
January 1, 1984
Subject Category
Communications And Radar
Report/Patent Number
NASA-TM-86872
E-2301
NAS 1.15:86872
Meeting Information
Meeting: Antenna Appl. Symp.
Location: Montecello, IL
Country: United States
Start Date: September 18, 1984
End Date: September 21, 1984
Sponsors: Illinois Univ.
Accession Number
85N10234
Funding Number(s)
PROJECT: RTOP 506-58-22
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
No Preview Available