Theory and Practice of Modern Antenna Range Measurements, Volume 1

Description

Cover Contents Volume 1 About the authors List of Abbreviations Foreword to volumes 1 and 2 Preface to volumes 1 and 2 1 Introduction 1.1 The phenomena of antenna coupling 1.2 Characterisation via a measurement process 1.3 Measurable properties of antennas 1.3.1 Antenna gain and directivity 1.3.2 Antenna cross-section 1.3.3 Free-space radiation pattern 1.3.4 Polarisation 1.3.5 The far-field 1.3.6 The phase in the measurement 1.3.7 Reciprocity 1.3.8 Measurement limitations 1.4 The content of this text References 2 EM theory and the mechanism behind antenna coupling 2.1 Maxwell’s classical electromagnetic field theory 2.2 Electric charge and EM fields 2.3 Power flux in an EM field 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 electromagnetic fields 2.9 Reflection and scattering of electromagnetic fields by extended objects 2.10 Antenna port definition 2.11 Summary References 3 Antenna measurements 3.1 Antenna measurements and alignment 3.2 Rotation methodologies 3.3 Far-field ranges 3.4 Free-space conditions 3.4.1 Far-field chambers 3.5 Alternatives to conventional far-field ranges 3.5.1 Tapered anechoic chambers 3.5.2 The compact antenna test range 3.5.3 Indirect measurements 3.5.3.1 Spherical near-field ranges 3.5.3.2 Planar near-field measurements 3.5.3.3 Cylindrical near-field measurements 3.5.3.4 Other geometries for scanning measurements 3.6 Antenna test range RF test equipment 3.6.1 RF instrumentation for test ranges 3.6.1.1 Receivers and sources 3.6.1.2 Down conversion mixers and up conversion multipliers 3.6.1.3 Amplifiers 3.6.1.4 Probes 3.6.1.5 Couplers 3.6.1.6 Switches 3.6.1.7 Attenuators 3.6.1.8 RF cables 3.6.1.9 Integrated facility instrumentation 3.6.2 Generic near-field antenna measurement process 3.7 Summary References 4 Antenna pattern plotting: coordinate systems and polarisation bases 4.1 Coordinate systems and antenna measurements 4.1.1 Azimuth over elevation 4.1.2 Elevation over azimuth 4.1.3 Polar spherical 4.1.4 True-view (azimuth and elevation) 4.1.5 Direction cosine 4.1.6 Arcsine-space plotting coordinate system 4.1.7 Transformation between coordinate systems 4.1.8 Coordinate systems and elemental solid angles 4.1.9 One-dimensional great circle pattern cuts 4.2 Polarisation basis and antenna measurements 4.2.1 Ludwig I (Cartesian) 4.2.2 Polar spherical 4.2.3 Ludwig II (Az/El, El/Az) 4.2.4 Ludwig III (co-polar, cross-polar and cross-polar discrimination) 4.2.5 Conversion between polarisation bases 4.2.5.1 Conversion from polar spherical to azimuth over elevation bases 4.2.5.2 Conversion from polar spherical to elevation over azimuth bases 4.2.5.3 Conversion between LII definitions 4.2.6 Elliptical polarisation, axial ratio and tilt angle 4.2.7 Linear and circular polarisation bases – complex vector representations 4.2.8 Measures of polarisation discrimination 4.3 Isometric rotation of coordinate systems 4.3.1 Illustration of the problem with antenna pattern plotting – Gauss’s Theorema Egregium 4.3.2 Use of direction cosine matrices in the rotation of coordinate systems 4.3.3 Azimuth, elevation and roll angles 4.3.4 Euler angles 4.3.5 Quaternions 4.3.6 Orientation of viewer plotting antenna patterns 4.3.7 Plotting antenna patterns on earth maps References 5 Compact range measurements 5.1 Introduction 5.2 Collimation of electromagnetic fields 5.2.1 Reflector edge diffraction 5.2.1.1 Serrated edge reflectors 5.2.1.2 Blended rolled edges 5.2.1.3 Shaped feed illumination 5.2.2 Feed spillover 5.2.3 Lenses as collimators 5.2.4 Hologram CATRs 5.2.5 Reflector surface errors and panel gaps 5.2.6 Time-gating and the absorber-less chamber 5.3 Types of ranges and their design issues 5.3.1 Single-offset reflector CATR 5.3.2 Dual cylindrical reflector CATR 5.3.3 Dual shaped reflector CATR 5.3.4 Tri-reflector CATR 5.3.5 Hologram CATR 5.3.6 Lens CATR 5.4 Quiet zones and performance evaluation 5.4.1 How does a CATR actually work? 5.4.2 Measurement of the quiet zone by field probing 5.4.3 Phase-less quiet zone scanning 5.4.4 Quiet zone evaluation using RCS of a known target 5.4.5 Improving measured CATR patterns 5.4.5.1 Mathematical absorber reflection suppression (MARS) 5.4.5.2 Antenna pattern comparison (APC) methods 5.4.6 Feed scanning for static AUT measurements 5.5 Radiation pattern and power parameter measurement 5.5.1 Radiation pattern measurement 5.5.2 Power parameter measurement 5.5.2.1 Gain measurement using the substitution technique 5.5.2.2 The three-antenna gain method 5.5.2.3 Direct gain measurement 5.5.2.4 EIRP measurement 5.5.2.5 Saturating flux density measurement 5.6 Radar cross-section measurements 5.6.1 RCS measurement in a CATR 5.6.2 Sources of RCS measurement error in a CATR 5.6.3 RCS model towers 5.6.4 Time-gating for RCS 5.6.5 Target imaging 5.7 Radome testing 5.7.1 Radome measurements in a CATR 5.7.2 Positioner overview – mechanically scanned AUTs 5.7.3 Measurement of reflectivity, transmission efficiency, pattern distortion, boresight shift, flash lobe 5.7.3.1 Reflectivity 5.7.3.2 Transmission efficiency 5.7.3.3 Pattern distortion 5.7.3.4 Boresight shift 5.7.3.5 Flash lobe 5.7.4 Examples of radome measurement ranges 5.8 Satellite testing 5.8.1 Satellite and telecommunications payload testing in a CATR 5.8.2 End-to-end testing and the compensated CATR 5.8.3 EIRP measurements 5.8.4 SFD measurements 5.8.5 G/T measurements 5.8.6 Group delay measurements 5.9 OTA testing for 5G antennas 5.9.1 Simulating a communications system using OFDM References 6 Planar near-field antenna measurements 6.1 Introduction 6.2 Near-field measurement facility 6.2.1 RF sub-system 6.2.2 Robotics positioner system 6.2.3 Near-field probe 6.3 Limitations in the accuracy of the near-field measurement data 6.3.1 Mechanically based limitations 6.3.2 RF system limitations 6.4 Solution of Maxwell’s equations in Cartesian coordinates 6.4.1 Plane wave spectrum 6.5 Probe pattern compensation 6.5.1 Effect of the probe pattern on far-field data 6.5.2 Scanning probe characteristics 6.6 Plane-polar near-field antenna measurements 6.6.1 Application of spectral methods to plane-polar antenna measurements 6.6.2 Conventional and alternate plane acquisition types 6.6.3 Plane-polar alignment 6.6.4 Remaining data acquisition factors of planar scanning 6.7 Sampling (interpolation theory) and aliasing 6.8 Finer than Nyquist sampling 6.9 Introduction to non-canonical near-field scanning – planar transform example 6.10 Electro-optical planar near-field scanning 6.11 Summary References 7 Cylindrical near-field antenna measurements 7.1 Introduction 7.2 Solution of Maxwell’s equation in cylindrical coordinates 7.3 Solution of the scalar wave equation in cylindrical coordinates 7.4 Construction of vector fields 7.5 Derivation of cylindrical mode coefficients from cylindrical near-field data 7.5.1 Orthogonality properties of cylindrical wave vectors 7.5.1.1 Property A 7.5.1.2 Property B 7.5.1.3 Properties C and D 7.5.2 Determining cylindrical mode coefficients from measured near electric field components 7.5.2.1 Derivation of B1 cylindrical mode coefficients 7.5.2.2 Derivation of B2 cylindrical mode coefficients 7.6 Derivation of asymptotic far-field parameters from cylindrical mode coefficients 7.7 Development of the transmission formula 7.7.1 The coupling equation – derivation of probe-compensated cylindrical near-field antenna measurements 7.7.2 Probe and test antenna 7.7.3 Effect of probe compensation in cylindrical near-field measurements 7.7.4 Calculation of probe cylindrical mode coefficients from far-field data 7.8 Sampling requirements for cylindrical near-field measurements 7.9 Implementation of cylindrical near-field to far-field transformation 7.10 Conical near-field antenna measurements 7.11 Summary References Index Back Cover