How to measure in the near field and in the far field. Figure 4 antenna nearfield onaxis power density normalized for various aperture illuminations. Near field antenna measurements shows you how to calculate antenna gain, pattern, and beam pointing faster and more accurately than ever before. Principles of planar nearfield antenna measurements stuart. Nf sites allow for hologram analysis, low sidelobes characterization, and do not require a rotating pedestal capable of bearing the weight of the phased array. In this article, antenna patterns measured by the developed system are. Introduction this paper describes the efforts of several groups of scientists and engineers to determine the side lobes of a very lowsidelobe array antenna using the nearfield technique and to. Application of the global optimization approaches to. Planar near field antenna measurements using nonideal measurement locations. May 14, 2008 at last, a musthave complete reference source for the foundations, principles and practice of planar near field antenna measurements. Principles of planar nearfield antenna measurements. Study of radiation characteristics for reflector antennas using the planar near field measurements of primary feed with area truncation level michio takikawa 1, yoshio inasawa 1, hiroaki miyashita 1. Uncertainty considerations in spherical nearfield antenna. In this article, this volume has been penned for a very specific purpose.
For various aperture illuminations for far field measurements. Request pdf the principles of planar near field antenna measurements, this single volume provides a comprehensive introduction and explanation of both the theory and practice of planar. Small vertical planar nearfield measurement systems can be supplied with a variety of options and can be upgraded to allow for cylindrical or spherical measurements to expand system utility. Nearfield antenna measurements shows you how to calculate antenna gain, pattern, and beam pointing faster and more accurately than ever before. A single data set provides information on antenna gain, side lobes structure, beam pointing and cross polarization. In planar nearfield measurements the radiated field is measured on a flat rectangular surface in front of an antenna aut. Yaghjw, senior member, eee abstractafter a brief history of nearfield antenna measurements with and without probe correction, the theory of nearfield antenna. Exceptions though certain applications use a half wave dipole antenna as a reference antenna, but use of the concept of isotropic radiator is. The development of very lowsidelobe antennas raises the question whether this technique can be used to accurately measure these antennas. The principles are presented in user friendly math from the maxwellian basis, to the plane wave spectra, to the latest advances. Nearfield farfield antenna measurements springerlink. Application of the global optimization approaches to planar nearfield antenna phaseless measurements jan puskely, zdenek novacek dept. To do this the book initially examines the properties of antennas that allow them to enhance the free.
At last, a musthave complete reference source for the foundations, principles and practice of planar near field antenna measurements. Abstract the planar near field measurement technique is a proven technology for measuring ordinary antennas operating in the microwave region. In fact, rigorous threedimensional probe correction, as pioneered by kerns, distinguishes modem near field antenna measurements from less accurate, nonprobecorrected near field measure ments that could have been formulated shortly after maxwell. The theoretical treatment of the method is detailed. Institute of high frequency technology planar nearfield. We propose a new antenna diagnostics technique for spherical near field. We will use the source antenna to illuminate the antenna under test with a plane wave from a specific direction. Antenna diagnostics on planar arrays using a 3d source. This paper describes the development of a spherical nearfield to farfield transform that can efficiently process data acquired on a nonuniform grid. Back projection allows one to transform the measured tangential efields to the fields across the aperture of the aut. The nearfield measurement scanner has provided a versatile testing method for satellite high gain datalink antennas. Variations of the spatial field strength, resulting from either amplitude or phase variations, are subject to averaging. Shafai, exploration of the feasibility of adaptive spherical nearfield antenna measurements part ii, in proc. The idea of planar cuts such as eplane or hplane are introduced for measuring 3d radiation patterns.
Antenna measurements through planar near field apparatus. The nearfield of dualchannel qon system at the output position has been obtained by a planar scanning in the two dimensions, where the sampling space can be chosen as dx dy principles of planar nearfield antenna measurements 9. Typically measurements are made using using a nearfield spherical or planar antenna measurement setup, in this case planar, where there is a distance z 0 between the probe and the antenna under test aut. The near field measurement scanner has provided a versatile testing method for satellite high gain datalink antennas. Frequency range 750mhz to 60ghz, dimensions 8m x 6m x sm, measurement capability as above. Computational electromagnetic model of a planar nearfield measurement process. Hessy, peter meincke, oscar borries, cecilia cappellin and jeff fordhamy ticra l. Error analysis techniques for planar near field measurements author. Adaptive spherical nearfield antenna measurements, in proc.
Apr 12, 2016 we present the design and characterization of planar mmwave patch antenna arrays with waveguidetomicrostrip transition using both near and far field methods. Planar nearfield measurements of lowsidelobe antennas. Pdf phaseless near field antenna measurements from two. The main factor which limits emf measurement accuracy in the near field is the antenna dimensions. Study of radiation characteristics for reflector antennas. Somewhere along line r9, the near field ends,and the far field begins. Analysis, national bureau of standards, boulder, october 1975. The nsi planar nearfield to farfield antenna measurement scanner is an ideal system for measuring medium and high gain antennas 15 dbi with small apertures, making it suitable for testing feeds and small arrays or. Electronic warfare and radar systems engineering handbook. Antenna diagnostics on planar arrays using a 3d source reconstruction technique and spherical nearfield measurements erik jorgensen, doren w.
Spherical nearfield farfield transformation for quasi. This book represents the specific measurement technique known as the spherical near field method. Abstract the planar nearfield measurement technique is a proven technology for measuring ordinary antennas operating in the microwave region. Before sharing sensitive information, make sure youre on a federal government site. Figure 3 shows an antenna with two lines, r and r9 line r traverses from a point along the antenna at z to point p in space. Moreover, the transformations are mathematically simple to describe and easy to implement.
Near field measurements require a sensitive and accurate mechanical infrastructure as well as a mathematical transformation of the near field data to far field. Jan 25, 2012 typically measurements are made using using a near field spherical or planar antenna measurement setup, in this case planar, where there is a distance z 0 between the probe and the antenna under test aut. Phaseless near field antenna measurements from two surface scans numerical and experimental investigations article pdf available in ieee transactions on antennas and propagation pp99. Line r 9goes from the midpoint of the antenna to point p. When exploring the topic of nearfield to farfield transformation, i found various methods on how to complete the task of producing a farfield pattern from nearfield measurements, such as multiple unclear ways on how to produce an angular map of the transformed data. In planar near field measurements the radiated field is measured on a flat rectangular surface in front of an antenna aut. Point antennas would be the best to use, because otherwise an antenna causes averaging of the measured emf values. Near field source solution is based on field equivalence principle the field equivalence principle states that original sources j and m which produce e and h fields, picture a. Study of radiation characteristics for reflector antennas using the planar nearfield measurements of primary feed with area truncation level.
Error analysis techniques for planar near field measurements. Application of the global optimization approaches to planar. Emphasizing practical solutions to realworld problems, it presents a detailed technical overview of the theory and practice of antenna near field measurements. The issue then becomes transforming the data acquired with nonuniform spacing.
Small vertical planar nearfield measurement system. Pdf principles of planar nearfield antenna measurements. Received 15 december 2012, accepted 25 january 20, scheduled 27. So far, several techniques, commonly based on far field, planar or spherical near field measurements, have been developed, all presenting limitations in their practical and theoretical realization 12. Introduction this paper describes the efforts of several groups of scientists and engineers to determine the side lobes of a very lowsidelobe array antenna using the near field technique and to. The geometry of the diagram shows that r 9is longer than r. Near field nf ranges offer a convenient alternative to compact antenna test ranges catr and anechoic far field ranges for the measurement of phased arrays 1,2,3,4,5,6,7,8,9. So far, several techniques, commonly based on farfield, planar or spherical nearfield measurements, have been developed, all presenting limitations in their practical and theoretical realization 12. Planar, cylindrical and spherical nearfield scanning capability for antennas up to about 2. There are three test configurations available for nearfield measurements. In order to obtain a lowcost, maintainable and native near field antenna measurement system, an engineering study was conducted in tubitak bilgem uekae emc laboratory and a near field measurement system was developed. Antenna measurements, phased arrays, near field scanners, planar near field, data acquisition. This single volume provides a comprehensive introduction and explanation of both the theory and practice of planar nearfield antenna measurement from its basic postulates and assumptions, to the intricacies of its deployment in complex and demanding measurement scenarios. Jan 15, 2014 when exploring the topic of near field to far field transformation, i found various methods on how to complete the task of producing a far field pattern from near field measurements, such as multiple unclear ways on how to produce an angular map of the transformed data.
Thus the isotropic antenna is a theoretical reference antenna. The isotropic antenna or radiator is a conceptual lossless radiating antenna with which any practical radiating antenna is compared. Planar nearfield antenna measurements using nonideal. Nearfield antenna measurements short course course description this course will cover theoretical and practical aspects of nearfield antenna testing. Yaghjian, upperbound errors in farfield antenna parameters determined from planar nearfield measurements, nbs tech. The general idea and necessary steps are indicated. In turn they shorten the distance between antenna under test aut and measuring probe to several times of the wavelength of measurement frequency. The intended audience is engineers and technicians using and operating nsimi nearfield antenna test systems. Again, as stated in the preface, to do this the volume will confine itself to considering the radiative coupling between electronic systems in free space for a number of very sound reasons. Field measurements for the validation of antennas are, in current practice, obtained in the near field region nearer to the antenna than where the ultimate angular intensity pattern is apparent to improve measurement quality and reduce cost. Antenna diagnostics back projection using planar nearfield.
The principles of planar near field antenna measurements. Measurements practicalities of planar nearfield antenna measurements. Theoretical basis for planar near field measurements l scattering matrix theory developed by dr. Full text pdf 1106k browse advance publication version.
Antenna diagnostics back projection using planar near. Measuring an antenna s radiation pattern and gain is discussed. Near and farfield characterization of planar mmwave. We propose a new antenna diagnostics technique for spherical nearfield. The polarization and antenna gain for the fields radiated toward the test antenna of the source antenna should be known. The approach provides a good alternative to space limited direct far. This book represents the specific measurement technique known as the spherical nearfield method. If in the antenna nearfield can estimate uncertainty. Posted on january 7, 2008 a book, principles of planar nearfield antenna measurements, coauthored by prof clive parini, together with antennas group collaborators stuart gregson and john mccormick, has been published by the institution of engineering and technology in december 2007. The subject of antenna measurements is one which has undergone revolutionary changes in recent years, in particular within space applications, where high demands are placed upon antenna design and construction.
Now that we have our measurement equipment and an antenna range, we can perform some antenna measurements. When free space measurements are performed at a known distance from a source, it is often necessary to know if the measurements are being performed in the far field. Emphasizing practical solutions to realworld problems, it presents a detailed technical overview of the theory and practice of antenna nearfield measurements. This geometry allows a simple and inexpensive mechanical setup. Field measurements for the validation of antennas are, in current practice, obtained in the nearfield region nearer to the antenna than where the ultimate angular intensity pattern is apparent to improve measurement quality and reduce cost. These results have been achieved by assuming the aut as enclosed in a prolate or oblate ellipsoid and by developing an optimal. This paper describes the development of a spherical near field to far field transform that can efficiently process data acquired on a nonuniform grid.
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