Near-field (NF) measurement techniques and the related NF to far-field (FF) transformations are gaining interest for their ability to allow an accurate evaluation of the radiation characteristics of those antennas whose electric sizes do not make it possible to perform direct FF measurements in a controlled and reflection-free environment, such as the anechoic chamber.
This book provides a comprehensive treatment of classical NF-FF transformation techniques and describes the significant improvements achieved in their performance by correctly applying the non-redundant sampling representations of antenna radiated electromagnetic (EM) fields.
Non-Redundant Near-Field to Far-Field Transformation Techniques is designed to meet the needs of students of antenna NF measurements, as well as of engineers and physicists working in the area. It has been written keeping in mind the fulfilment of two main objectives. The former is to provide all the analytical details on the derivation of the classical NF-FF transformation techniques without and with probe compensation, which are not easily available elsewhere in the literature. The latter is to give a comprehensive description of effective representations of the EM fields radiated over arbitrary rotational surfaces, which make use of a non-redundant (i.e., minimum) number of samples collected on these surfaces or along proper spirals wrapping them.
Author(s): Claudio Gennarelli, Flaminio Ferrara, Rocco Guerriero, Francesco D'Agostino
Series: IET Energy Engineering Series, 549
Publisher: Scitech Publishing
Year: 2023
Language: English
Pages: 305
City: London
Contents
About the Authors
Preface
1 Introduction
1.1 Motivation and background
1.2 The versatile NF facility at the UNISA antenna characterization lab
1.3 Structure of the book
2 Non-redundant sampling representations of electromagnetic fields
2.1 The choice of the optimal parameterization and phase factor
2.2 Spheroidal source modellings
2.3 Flexible source modellings
2.4 Cardinal series representations
2.5 Optimal sampling interpolation expansions
2.6 Application to far-field interpolation
Appendix
2A.1 Some details on the evaluation of the azimuthal bandwidth
2A.2 Number of samples to represent the field on a closed surface surrounding the source
2A.3 Evaluation of the optimal parameter and phase factor: spheroidal modellings
2A.4 On the choice of the azimuthal enlargement bandwidth factor
2A.5 On the Tschebyscheff sampling function
3 Theoretical foundations of spiral scannings
3.1 The unified theory of spiral scannings for quasi-spherical antennas
3.2 The unified theory of spiral scannings for non-spherical antennas
3.3 The spheroidal spiral case
4 Near-field to far-field transformations in planar scanning geometry
4.1 Introduction
4.2 Classical plane-rectangular NF-FF transformation without probe compensation
4.3 Classical plane-rectangular NF-FF transformation with probe compensation
4.4 Error due to the truncation of the scanning area
4.5 Non-redundant NF-FF transformations with non-conventional plane-rectangular scanning
4.5.1 NF-FF transformation with planar wide-mesh scanning: the oblate spheroidal modelling case
4.5.2 NF-FF transformation with planar wide-mesh scanning: the double bowl modelling case
4.6 Non-redundant NF-FF transformations with plane-polar scanning
4.6.1 Non-redundant NF-FF transformation with plane-polar scanning: the oblate spheroidal modelling case
4.6.2 Non-redundant NF-FF transformation with plane-polar scanning: the double bowl modelling case
4.7 Non-redundant NF-FF transformations with bi-polar scanning
4.7.1 Non-redundant NF-FF transformation with bi-polar scanning: the oblate spheroidal modelling case
4.7.2 Non-redundant NF-FF transformation with bi-polar scanning: the double bowl modelling case
4.8 Non-redundant NF-FF transformations with planar spiral scanning
4.8.1 NF-FF transformation with uniform planar spiral scanning
4.8.2 Non-redundant NF-FF transformation with planar spiral scanning: the double bowl modelling case
4.8.3 Non-redundant NF-FF transformation with planar spiral scanning: the oblate spheroidal modelling case
Appendix
4A.1 Plane wave expansion
4A.2 Relation between the antenna far field and the plane wave spectrum
4A.3 Relevant to the probe-compensated PR NF-FF transformation
4A.4 On the software co-rotation
5 Near-field to far-field transformations in cylindrical scanning geometry
5.1 Introduction
5.2 Classical cylindrical NF-FF transformation without probe compensation
5.3 Classical cylindrical NF-FF transformation with probe compensation
5.4 Error due to the truncation of the scanning area
5.5 Non-redundant NF-FF transformations with cylindrical scanning
5.5.1 Non-redundant cylindrical NF-FF transformation: the prolate spheroidal modelling case
5.5.2 Non-redundant cylindrical NF-FF transformation: the rounded cylinder modelling case
5.5.3 Direct non-redundant NF-FF transformation with cylindrical scanning
5.6 Half-wavelength helicoidal scanning
5.7 Non-redundant NF-FF transformations with helicoidal scanning
5.7.1 NF-FF transformation with uniform helicoidal scanning
5.7.2 Non-redundant helicoidal NF-FF transformation: the prolate spheroidal modelling case
5.7.3 Non-redundant helicoidal NF-FF transformation: the rounded cylinder modelling case
Appendix
5A.1 Cylindrical wave expansion
5A.2 Cylindrical wave expansion valid in the antenna far-field region
6 Near-field to far-field transformations in spherical scanning geometry
6.1 Introduction
6.2 Classical spherical NF-FF transformation without probe compensation
6.3 Classical spherical NF-FF transformation with probe compensation
6.4 Non-redundant NF-FF transformations with spherical scanning
6.4.1 Non-redundant spherical NF-FF transformations: spheroidal AUT modellings
6.4.1.1 The oblate modelling case
6.4.1.2 The prolate modelling case
6.4.2 Non-redundant spherical NF-FF transformations: flexible AUT modellings
6.4.2.1 The rounded cylinder modelling case
6.4.2.2 The double bowl modelling case
6.5 Non-redundant NF-FF transformations with spherical spiral scanning
6.5.1 Non-redundant NF-FF transformations with spherical spiral scanning: spheroidal AUT modellings
6.5.1.1 The prolate modelling case
6.5.1.2 The oblate modelling case
6.5.2 Non-redundant NF-FF transformations with spherical spiral scanning: flexible AUT modellings
6.5.2.1 The double bowl modelling case
6.5.2.2 The rounded cylinder modelling case
Appendix
6A.1 Spherical wave expansion
Appendices
A.1 Radiation and auxiliary vector potentials
A.2 Solution of the scalar Helmholtz equation in cylindrical coordinates
A.3 Solution of the scalar Helmholtz equation in spherical coordinates
A.4 Method of the stationary phase
A.4.1 Single integrals
A.4.2 Double integrals
A.5 The fast Fourier transform
References
Index
