A brief history of the development of the near-field measurement technique at the Georgia Institute of Technology

Abstract

The activity of the Georgia Institute of Technology in the development of the near-field measurement technique is reviewed. The work conducted during the years 1967-1973 is given primary importance, and the major near-field developments in the 1973-1980 time period are also briefly described.HE GEORGIA Institute of Technology has historically T had a strong interest in antenna measurement techniques. Scientific-Atlanta, Inc. is a Georgia Tech spin-off company formed in the mid-1950's to produce instrumentation for antenna measurements. The reflector compact antenna measurement technique was developed at Georgia Tech in the mid-1960's under the leadership of Richard C. Johnson. Georgia Tech was awarded a patent for the compact antenna measurement range in 1967 [l].Also in the mid-l960's, Demetrius T. Paris became interested in the near-field behavior of antennas in his study of radomes, which are often located in the radiating near field of an antenna. He showed that greater accuracy in far-field pattern calculation of an antenna can be achieved using the vector formulation of the diffraction equation which requires knowledge of both the electric and magnetic aperture fields versus the scalar formulation which requires knowledge of only one. These results were published in 1968 [2]. He likewise formulated a radome analysis technique which required knowledge and manipulation of both the electric and magnetic near fields of an antenna, as presented in a 1970 J . Searcy Hollis and Larry Clayton, Jr., of ScientificAtlanta had envisioned the practicality of planar surface nearfield measurements and had performed amplitude and phase near-field measurements of a Ku-band antenna, compared the calculated far-field patterns to measured far-field patterns and published these results as early as 1960 [4]. They used the scalar diffraction integral of the planar surface aperture fields to calculate the far-field pattern of the antenna. The scalar diffraction integral reduces to a Fourier transform of the planar surface aperture fields for far-field determination. Toward this end, Scientific-Atlanta had developed a 100-in by 100-in planar scanner, a phase-amplitude receiver, and a Fourier integral analog computer by 1961. paper ~31.Paris approached Scientific-Atlanta in his search for research support for his graduate student, the writer of this paper, in 1967. The topic of mutual interest was the theory and practical implementation of planar surface near-field measurements. Scientific-Atlanta provided a three-year research assistantship for the writer and donated a 100-in by 100-in planar scanner and associated manual position control unit to Georgia Tech. Over the course of the following three years, Hollis educated the writer in the state of the art in antenna measurement techniques including the pioneering work conducted at Scientific-Atlanta in near-field antenna measurements.The planar scanner was assembled in the basement of the Electronics Research Building of the Georgia Tech Engineering Experiment Station. The basement...

Realization of Wideband Hologram Compact Antenna Test Range by Linearly Adjusting the Feed Location

“…Therefore, in practice, the down distance or the distance from the hologram to the quiet zone, , needs to be (6) where is the size of the quiet zone. Equation (6) is derived similarly as the angle of validity in the near field measurements [2], [4]. The distance is empirically set to be .…”

“…The environment can be controlled, and thus, the atmospheric effects become less severe. The near field amplitude and phase need to be sampled discretely with a probe over a surface close to the AUT and the far-field pattern can be calculated by numerical algorithms [3], [4]. The sampling has usually to be dense enough to satisfy the Nyquist sampling criteria.…”

Near‐Field Scanning Measurements: Theory and Practice

“…transformation based on a scattering-matrix approach. A detailed history of the development of near-field scanning methods can be found in Gillespie [13], especially the papers by Baird et al [14], Hansen and Jensen [15], and Joy [16]. An extensive bibliography is given in these historical papers and also in Yaghjian [17].…”