Accession Number : ADA117744

Title :   Ultralow Sidelobe Planar Near Field Measurement Study.

Descriptive Note : Final rept. 1 Jan-30 Jun 82,


Personal Author(s) : Grimm,K R

PDF Url : ADA117744

Report Date : 30 Jun 1982

Pagination or Media Count : 79

Abstract : An analytic study has extended existing methods of estimating antenna pattern errors when testing by the method of planar near field probing. Improved error bounds are given for very low sidelobe levels based only on the measured near field data and known tolerances due to probe positioning and multipath. These bounds are useful for certifying array performance independent of standard far field antenna range tests. They also can serve as improved design criteria for the construction of quality near field testing systems. An optimum probe for low sidelobe testing is shown to be one which minimizes its back scatter while simultaneously contributing minimum mean square error to the sidelobe region. That this is impossible for the commonly used dominant-mode waveguide probes is shown, and a recommendation is made to design an alternate probe based on single (or small array cluster) of radial mode dipoles. Finally, the feasibility of a highly thinned measurement/processing technique is shown using existing Navy-owned near field data from a moderate sidelobe array. The principle study recommendation is to confirm the improved error estimates developed herein by conducting a test of a qualified very low sidelobe array at the National Bureau of Standards, in order to demonstrate the fundamental limits of measurement accuracy of planar near field probing. (Author)

Descriptors :   *Antenna radiation patterns, *Antenna arrays, *Sidelobes, Error analysis, Near field, Scanning, Waveguides, Short range(Distance), Accuracy, Far field, Measurement, Multipath radar

Subject Categories : Electrical and Electronic Equipment
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE