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This work concerns the development of an efficient near-fleld/far-field (NF/FF) transformation with spherical scan for an offset mounted antenna under test (AUT), with a quasi-planar shape, employing a number of NF data minimum and practically equal to that for a centred mounting. Such a result has been achieved by applying the nonredundant sampling representation of electromagnetic fields to the...
Measurement techniques in the antenna near-field (NF) region play a significant role in the evaluation of far-field (FF) patterns. In fact, for electrically large antennas, the required size of the conventional FF range becomes prohibitively large. Moreover, the development and the spreading of NF-FF transformation techniques employing planar, cylindrical or spherical scanning systems is justified...
This work provides the experimental assessment of an efficient technique which allows the correction of known positioning errors in a near-field — far-field (NF-FF) transformation with bipolar scan requiring a minimum number of NF data. The NF-FF transformation uses a 2-D optimal sampling interpolation expansion, obtained by modeling the antenna under test with an oblate ellipsoid and applying the...
A non-redundant near field — far field (NF-FF) transformation technique with spherical scanning for offset mounted quasi-planar antennas is here proposed. Unlike the classical NF-FF transformation, it allows the reconstruction of the far field radiated by the antenna under test (AUT) from a minimum number of NF data, which does not change when the AUT is mounted in an offset configuration. This interesting...
This communication concerns the experimental validation of a probe compensated near-field — far-field (NF-FF) transformation technique with bi-polar scanning for quasi-planar antennas requiring a minimum number of NF data. Such a technique properly exploits the nonredundant sampling representations of the electromagnetic fields to obtain an efficient representation of the voltage measured by the probe...
An effective probe compensated near-field - far-field (NF-FF) transformation with spherical scanning for an offset mounted long antenna, requiring a number of NF data that is minimum and equal to that needed in a centred configuration, is developed in this work, by applying the nonredundant sampling representations of the electromagnetic field and modelling the antenna under test (AUT) by a prolate...
Two fast and accurate probe compensated planar spiral near-field–far-field (NF–FF) transformation techniques, using nonredundant NF data, are experimentally assessed. These techniques allow a remarkable measurement time saving since they require a reduced number of NF data, which are collected on fly by properly and continuously moving the positioners. They have been achieved by applying the unified...
This work concerns the development of an optimal sampling interpolation algorithm in the time domain, which allows a very efficient reconstruction of the transient field over a plane in the near field region from a minimum number of data acquired via a nonconventional plane-rectangular scanning. This result is obtained by properly exploiting the nonredundant sampling representations of electromagnetic...
A technique to effectively compensate known positioning errors in a near field — far field (NF-FF) transformation with plane-polar scanning, requiring a minimum number of NF data and adopting an oblate ellipsoid to model the antenna under test, is proposed. It makes use of an iterative scheme to recover the probe voltage samples at the points fixed by the nonredundant sampling representation from...
An efficient near-field - far-field (NF-FF) transformation with planar spiral scanning particularly suitable for quasi-planar antennas is experimentally validated. It relies on a nonredundant sampling representation of the voltage measured by the probe, obtained by applying the unified theory of spiral scan for nonspherical antennas and assuming that the antenna under test is enclosed in a surface...
An efficient near-field - far-field (NF-FF) transformation with spherical scanning for long antennas, requiring a minimum number of irregularly spaced data, is experimentally validated in this work. It is based on a nonredundant sampling representation of the voltage measured by the probe, obtained by assuming the antenna under test as enclosed in a prolate ellipsoid, a modelling particularly suitable...
The experimental assessment of an effective near-field - far-field (NF-FF) transformation technique with plane-polar scanning, which requires a nonredundant, i.e. minimum, number of NF data, is provided in this communication. Such a technique relies on the nonredundant sampling representations of the electromagnetic fields and, to shape the antenna, adopts a surface formed by two circular bowls with...
An efficient technique for compensating known probe positioning errors in a nonredundant spherical near-field — far-field (NF-FF) transformation, using an oblate ellipsoid to model a quasi-planar antenna, is experimentally assessed in this work. It employs an iterative approach to recover the nonredundant NF samples at the points fixed by the sampling representation from the collected irregularly...
This work deals with the experimental validation of a probe compensated near-field — far-field (NF-FF) transformation with plane-polar scanning, which makes possible to lower the number of needed measurements, as well as the time required for the data acquisition when dealing with quasi-planar antennas. It relies on the use of the nonredundant sampling representations of electromagnetic fields, employing...
This work concerns the experimental validation of an efficient near-field - far-field (NF-FF) transformation using a nonconventional plane-rectangular scanning, particularly suitable from the NF data reduction and time saving viewpoints when dealing with quasi-planar antennas. Such a NF scanning technique has been named planar wide-mesh scanning, since the sample grid is characterized by meshes wider...
This communication provides the experimental assessment of an efficient near-field - far-field (NF-FF) transformation with spherical spiral scanning for elongated antennas, which allows a remarkable measurement time saving with respect to the classical spherical NF-FF transformation. Such a saving is due both to the use of continuous and synchronized movements of the positioning systems and to the...
An experimental validation of a near-field - far-field transformation technique with spherical scanning for quasi-planar antennas requiring a minimum number of near-field data is provided in this work. Such a technique is based on the nonredundant sampling representations of the electromagnetic fields and on the optimal sampling interpolation expansions, and makes use of an oblate ellipsoid to model...
Measurement techniques in the antenna near-field (NF) region have a significant role in the evaluation of far-field (FF) patterns. In fact, for electrically large antennas the required size of the conventional FF range becomes prohibitively large. Moreover, NF facilities provide a controlled and secure environment, and all weather capability. Among the NF-FF transformation techniques, that employing...
Among the near field-far field (NF-FF) transformation techniques, that employing the bi-polar scanning, proposed by Rahmat-Samii et al. in [1], is particularly attractive due to its peculiar characteristics. In such a scanning, the antenna under test (AUT) rotates axially, whereas the probe is attached to the end of an arm which rotates around an axis parallel to the AUT one. This allows one to collect...
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