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This paper provides the experimental assessment of an effective near-field-to-far-field (NF-FF) transformation technique with spherical-spiral scanning, particularly suitable for long antennas. Such a technique allows a remarkable measurement-time saving, due to the use of continuous and synchronized movements of the positioning systems, and due to the reduced number of required near-field measurements. This is made possible by a non-redundant sampling representation of the voltage measured by the probe, obtained by using the unified theory of spiral scans for non-spherical antennas, and adopting a prolate-ellipsoidal source modeling. The near-field data needed by the classical spherical near-field-to-far-field transformation are then efficiently retrieved from those acquired along the spiral by an optimal sampling interpolation formula. [ABSTRACT FROM AUTHOR]

Traditional wireless position-location systems, operating using propagating waves, suffer reduced performance in non-line-of-sight (NLoS) applications. Traditional systems that use quasistatic fields have instead been limited to short ranges, progressive direction-finding applications, require RF fingerprinting, or do not provide complete immunity to dielectric obstacles (use of electric fields). These limitations impose severe restrictions in applications such as tracking an American football during game play, where position and orientation tracking may be required over long ranges, and when the line-of-sight (LoS) is blocked by groups of people. A technique using magneto-quasistatic fields and complex image theory was recently shown to circumvent these problems, and to enable accurate long-range one-dimensional and two-dimensional measurements. In this work, we present three-dimensional position and orientation measurements using the magneto-quasistatic system and complex image theory over an area of 27.43 m ? 27.43 m. Inverting the theoretical expression for the voltage measured at the terminals of the receiving loops to determine three-dimensional position and orientation resulted in mean and median geometric position errors of 0.77 m and 0.71 m, respectively; inclination orientation mean and median errors of 9.67? and 8.24?, respectively; and azimuthal orientation mean and median errors of 2.84? and 2.25?, respectively. [ABSTRACT FROM PUBLISHER]

This article describes the possible factors that can introduce discrepancies between measurements and three-dimensional EM simulations of millimeter-wave (mm-wave) antennas. The effects of the choice of the simulation solver, the relative permittivity and the homogeneity of the substrate material, the manufacturing tolerance, and the measurement errors are discussed. It is concluded that a fair comparison between measurements and simulations of mm-wave antennas can only be made if all these possible causes of discrepancies are taken into account. [ABSTRACT FROM AUTHOR]

A key concern in making near-fi eld antenna measure ments is measurement time, since most often the use of near-fi eld processes entails stepping up to additional sampling. This month's Measurements Corner article features excellent antenna-measurement comparisons based on derived non-redundant minimum near-fi eld samples for two fundamentally different collection geometries. [ABSTRACT FROM AUTHOR]

This month's Measurements Corner article, by Ron Pogorzelski (Pogo, to many if us), features a very interesting application of a constrained iterative algorithm for solving a linear system of equations to the problem of antenna diagnostics. The paper presents both an intuitive description and a mathematical derivation of the technique, along with a numerical example of its capability. [ABSTRACT FROM PUBLISHER]