Rectilinear Planar Near-Field Measurements From the Perspective of the Synthetic Phased Array

• Published in: IEEE transactions on antennas and propagation Vol. 70; no. 10; pp. 9806 - 9818
• Main Authors: Cutshall, Ryan T., Dobbins, Justin A., Freking, Jacob A., Hertneky, Brandon J.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.10.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Amplitude taper; Antenna arrays; Antenna measurements; Antenna radiation patterns; Antennas; dipole antennas; Directivity; Electric fields; Far fields; measurement uncertainty; Near fields; Phase measurement; Phased arrays; planar near field; Plane waves; Probes; Tapering; Transmitting antennas; truncation; window
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2022.3191203

A new far-field valid angle equation for rectilinear planar near-field measurements is derived. The new valid angle equation is derived by viewing the near-field to far-field transformation process as the generation of a pseudo plane wave by a synthetic phased array and subjecting the antenna-under-test (AUT) to the radiation from this synthetic array. The synthetic phased array does not physically exist; rather, the array is formed during the postprocessing of the planar near-field measurements. The resultant valid far-field angle computed with the new equation is compared against previously established and popularly accepted valid angle equations. A brief discussion is offered on the measurement of low-directivity antennas with a planar near-field measurement system and on amplitude tapering of the near-field measurements to improve the quality of the pseudo plane wave inside the test zone.