Principles of Planar Near-Field Antenna Measurements

Abstract

The organisation of the book 1.4 References 2 Maxwell's equations and electromagnetic wave propagation 13 2.1 Electric charge 2.2 The EM field 2.3 Accelerated charges 2.4 Maxwell's equations 2.5 The electric and magnetic potentials 2.5.1 Static potentials 2.5.2 Retarded potentials 2.6 The inapplicability of source excitation as a measurement methodology 2.7 Field equivalence principle 2.8 Characterising vector EM fields 2.9 Summary 2.10 References 3 Introduction to near-field antenna measurements 3.1 Introduction 3.2 Antenna measurements vi Principles of planar near-field antenna measurements 3.3 Forms of near-field antenna measurements 3.4 Plane rectilinear near-field antenna measurements 3.5 Chambers, screening and absorber 3.6 RF subsystem 3.7 Robotics positioner subsystem 3.8 Near-field probe 3.9 Generic antenna measurement process 3.10 Summary 3.11 References Plane wave spectrum representation of electromagnetic waves 4.1 Introduction 4.2 Overview of the derivation of the P WS 64 4.3 Solution of the scalar Helmholtz equation in Cartesian coordinates 4.3.1 Introduction to integral transforms 4.3.2 Fourier transform solution of the scalar Helmholtz equation 4.4 On the choice of boundary conditions 4.5 Operator substitution (derivative of a Fourier transform) 4.6 Solution of the vector Helmholtz equation in Cartesian coordinates 4.7 Solution of the vector magnetic wave equation in Cartesian coordinates 4.8 The relationship between electric and magnetic spectral components 4.9 The free-space propagation vector k_ 4.10 Plane wave impedance 4.11 Interpretation as an angular spectrum of plane waves 4.12 Far-field antenna radiation patterns: approximated by the angular spectrum 4.13 Stationary phase evaluation of a double integral 4.14 Coordinate free form of the near-field to angular spectrum transform 4.15 Reduction of the coordinate free form of the near-field to far-field transform to Huygens' principle 4.16 Far-fields from non-planar apertures 4.17 Microwave holographic metrology (plane-to-plane transform) 4.18 Far-field to near-field transform 4.19 Radiated power and the angular spectrum 4.20 Summary of conventional near-field to far-field transform 4.21 References List of contents vn Measurements-practicalities of planar near-field antenna measurements 5.1

Riset Antena – State of the Art

“…Teknik pengukuran besaran-besaran antenna merupakan langkah yang sulit. Telah dikembangkan berbagai teknik pengukuran, yang di-standarisasi oleh IEEE [56] dan didokumentasikan dalam beberapa buku [57][58][59][60].…”

Indirect Off-Axis Holography for Antenna Metrology

“…Planar, cylindrical, or spherical surfaces are the most common acquisition surfaces, with recent extensions to arbitrary geometry [9] or noncanonical domains [10,11]. The acquired NF can be employed to obtain the FF radiation pattern of the antenna by means of mathematical NF-FF transformations based either in wave expansions [1,12,13] or integral equation methods such as the sources reconstruction method (SRM) [3,9]. Diagnostics applications can also be developed from NF data using backpropagation techniques toward the AUT aperture [1,13] or the SRM [3,9].…”

“…The acquired NF can be employed to obtain the FF radiation pattern of the antenna by means of mathematical NF-FF transformations based either in wave expansions [1,12,13] or integral equation methods such as the sources reconstruction method (SRM) [3,9]. Diagnostics applications can also be developed from NF data using backpropagation techniques toward the AUT aperture [1,13] or the SRM [3,9]. After several decades of research and development, NF ranges have become the preferred approach for antenna testing.…”

“…Special attention must be given to the probe pattern and positioning accuracy [1] as well as to the effects that error sources in NF acquisitions, such as truncation of the measurement plane, cable flexing, stray signals, leakage, etc., can introduce in the FF pattern of the AUT [1,2,13,14]. 1 The far-field distance is defined by R ¼ 2D 2 =λ (R >> λ), being D the maximum dimension of the antenna and λ the wavelength [1].…”

“…Nevertheless, phase acquisition, particularly at mm-and submm-wave bands, is a challenging task that requires sophisticated and expensive equipment due to the high thermal stability requirements and the effect of the errors, mostly resulting from thermal drift and cable flexing [1,[13][14][15][16].…”