Microwave Measurements. 3rd Edition. Edited by RJ. Collier and A.D. Skinner. The Institution of Engineering and Technology

Transcription

1 Microwave Measurements 3rd Edition Edited by RJ. Collier and A.D. Skinner The Institution of Engineering and Technology

2 Contents List of contributors Preface xvii xix 1 Transmission lines - basic principles 1 R. J. Collier 1.1 Introduction Lossless two-conductor transmission lines - equivalent circuit and velocity of propagation Characteristic impedance Reflection coefficient Phase velocity and phase constant for sinusoidal waves Power flow for sinusoidal waves Standing waves resulting from sinusoidal waves Two-conductor transmission lines with losses - equivalent circuit and low-loss approximation Pulses on transmission lines with losses Sinusoidal waves on transmission lines with losses Lossless waveguides Plane (or transverse) electromagnetic waves Rectangular metallic waveguides The cut-off condition The phase velocity The wave impedance' The group velocity General solution 16 Further reading 17 Scattering parameters and circuit analysis 19 P. R. Young i, 2.1 Introduction One-port devices 19

3 vi Contents 2.3 Generalised scattering parameters Impedance and admittance parameters Examples of S-parameter matrices Cascade parameters Renormalisation of S-parameters De-embedding of S-parameters Characteristic impedance Characteristic impedance in real transmission lines Characteristic impedance in non-tem waveguides Measurement of Zo Signal flow graphs 36 Appendices 37 2.A Reciprocity 37 2.B Losslessness 39 2.C Two-port transforms 40 References 41 Further reading 41 3 Uncertainty and confidence in measurements 43 John Hurll Introduction Sources of uncertainty in RF and microwave measurements RF mismatch errors and uncertainty Directivity Test port match RF connector repeatability Example - calibration of a coaxial power sensor at a frequency of 18 GHz References Using coaxial connectors in measurement 59 Doug Skinner 4.1 Introduction Coaxial line sizes Connector repeatability Handling of airlines Assessment of connector repeatability Coaxial connector specifications Interface dimensions and gauging Gauging connectors f Connector cleaning ' Cleaning procedure Cleaning connectors on static sensitive devices Connector life

4 Contents vii 4.7 Adaptors Connector recession Conclusions ' 66 4.A Appendix A 66 4.B Appendix B 66 4.C Appendix C 85 4.D Appendix D 86 4.E Appendix E ^ 87 Further reading 88 Attenuation measurement 91 Alan Coster 5.1 Introduction Basic principles Measurement systems Power ratio method Voltage ratio method The inductive voltage divider AF substitution method IF substitution method RF substitution method The automatic network analyser Important considerations when making attenuation measurements Mismatch uncertainty RF leakage Detector linearity Detector linearity measurement uncertainty budget System resolution System noise Stability and drift Repeatability Calibration standard A worked example of a 30 db attenuation measurement Contributions to measurement uncertainty 117 References 119 Further reading 120 RF voltage measurement 121 Paul C. A. Roberts i * 6.1 Introduction RF voltage measuring instruments Wideband AC voltmeters Fast sampling and digitising DMMs 124

5 viii Contents RF millivoltmeters Sampling RF voltmeters Oscilloscopes Switched input impedance oscilloscopes Instrument input impedance effects Source loading and bandwidth AC and RF/microwave traceability Thermal converters and micropotentiometers Impedance matching and mismatch errors Uncertainty analysis considerations Example: Oscilloscope bandwidth test Harmonic content errors Example: Oscilloscope calibrator calibration RF millivoltmeter calibration 140 Further reading Structures and properties of transmission lines 147 R. J. Collier Introduction Coaxial lines Rectangular waveguides Ridged waveguide Microstrip Slot guide Coplanar waveguide Finline Dielectric waveguide References Further reading Noise measurements David Adamson Introduction Types of noise Thermal noise Shot noise Flicker noise Definitions Types of noise source Thermal noise sources The temperature-limited diode Gas discharge tubes Avalanche diode noise sources

6 Contents IX Measuring noise The total power radiometer Radiometer sensitivity Measurement accuracy Cascaded receivers Noise from passive two-ports Mismatch effects Measurement of receivers and amplifiers Automated noise measurements Noise figure meters or analysers On-wafer measurements Conclusion t Acknowledgements References Connectors, air lines and RF impedance 179 N. M. Ridler 9.1 Introduction Historical perspective Coaxial connectors Coaxial air lines RF impedance Connectors Types of coaxial connector Mechanical characteristics Electrical characteristics Airlines Types of precision air line Air line standards Conductor imperfections RF impedance Airlines Terminations Future developments 200 Appendix: 7/16 connectors 201 References Microwave network analysers 207 Roger D. Pollard 10.1 Introduction Reference plane ', Elements of a microwave network analyser Network analyser block diagram 214 Further reading 216

7 x Contents 11 RFIC and MMIC measurement techniques 217 Stepan Lucyszyn 11.1 Introduction Test fixture measurements Two-tier calibration One-tier calibration Test fixture design considerations Probe station measurements Passive microwave probe design Probe calibration Measurement errors DC biasing MMIC layout considerations Low-cost multiple DC biasing technique Upper-millimetre-wave measurements Thermal and cryogenic measurements Thermal measurements Cryogenic measurements Experimental field probing techniques Electromagnetic-field probing Magnetic-field probing Electric-field probing Summary 254 References Calibration of automatic network analysers 263 Ian Instone Introduction Definition of calibration Scalar network analysers Vector network analyser Calibration of a scalar network analyser Transmission measurements Reflection measurements Problems associated with scalar network analyser measurements Calibration of a vector network analyser Accuracy enhancement What causes measurement errors? Directivity Source match Load match Isolation (crosstalk) Frequency response (tracking)

8 Contents xi 12.9 Characterising microwave systematic errors One-port error model One-port device measurement Two-port error model TRL calibration TRL terminology TrueTRL/LRL The TRL calibration procedure Data-based calibrations References Verification of automatic network analysers 291 Ian Instone ' 13.1 Introduction Definition of verification Types of verification Verification of error terms Verification of measurements Calibration scheme Error term verification Effective directivity Effective source match Effective load match Effective isolation Transmission and reflection tracking Effective linearity Verification of measurements Customised verification example Manufacturer supplied verification example 302 References Balanced device characterisation 305 BerndA. Schincke 14.1 Introduction ' Physical background of differential structures Characterisation of balanced structures Balanced device characterisation using network analysis Characterisation using physical transformers Modal decomposition method Mixed-mode-S-parameter-matrix Characterisation of single-ended to balanced devices Typical measurements 320

9 xii Contents 14.3 Measurement examples Example 1: Differential through connection Example 2: SAW-filter measurement (De)Embedding for balanced device characterisation 326 Further reading RF power measurement James Miall 15.1 Introduction 15.2 Theory Basic theory Mismatch uncertainty 15.3 Power sensors Thermocouples and other thermoelectric sensors Diode sensors Thermistors and other bolometers Calorimeters Force and field based sensors Acoustic meter 15.4 Power measurements and calibration Direct power measurement Uncertainty budgets 15.5 Calibration and transfer standards Ratio measurements 15.6 Power splitters Typical power splitter properties Measurement of splitter output match The direct method of measuring splitter output 15.7 Couplers and reflectometers Reflectometers 15.8 Pulsed power 15.9 Conclusion Acknowledgements References Spectrum analyser measurements and applications 349 Doug Skinner 16.1 Part 1: Introduction Signal analysis using a spectrum analyser f Measurement domains ' The oscilloscope display The spectrum analyser display Analysing an amplitude-modulated signal 351

10 Contents xiii 16.2 Part 2: How the spectrum analyser works Basic spectrum analyser block diagram Microwave spectrum analyser with harmonic mixer The problem of multiple responses Microwave spectrum analyser with a tracking preselector Effect of the preselector Microwave spectrum analyser block diagram Spectrum analyser with tracking generator Part 3: Spectrum analyser important specification points The input attenuator and IF gain controls Sweep speed control Resolution bandwidth c Shape factor of the resolution filter Video bandwidth controls Measuring low-level signals - noise Dynamic range Amplitude accuracy Effect of input VSWR Sideband noise characteristics Residual responses Residual FM Uncertainty contributions Display detection mode Spectrum analyser applications Measurement of harmonic distortion Example of a tracking generator measurement Zero span The use of zero span Meter Mode Intermodulation measurement Intermodulation analysis Intermodulation intercept point Nomograph to determine intermodulation products using intercept point method Amplitude modulation AM spectrum with modulation distortion Frequency modulation FM measurement using the Bessel zero method FM demodulation FM demodulation display Modulation asymmetry - combined AM and FM Spectrum of a square wave Pulse modulation Varying the pulse modulation conditions 389

11 xiv Contents 'Line' and 'Pulse' modes Extending the range of microwave spectrum analysers EMC measurements Overloading a spectrum analyser 16.5 Conclusion Further reading Measurement of frequency stability and phase noise 395 David Owen 17.1 Measuring phase noise Spectrum analysers Use of preselecting filter with spectrum analysers Delay line discriminator Quadrature technique FM discriminator method Measurement uncertainty issues Future method of measurements Summary Measurement of the dielectric properties of materials at RF and microwave frequencies 409 Bob Clarke 18.1 Introduction Dielectrics - basic parameters Basic dielectric measurement theory Lumped-impedance methods Wave methods Resonators, cavities and standing-wave methods The frequency coverage of measurement techniques Loss processes: conduction, dielectric relaxation, resonances International standard measurement methods for dielectrics Preliminary considerations for practical dielectric measurements Do we need to measure our dielectric materials at all? Matching the measurement method to the dielectric material Some common themes in dielectric measurement Electronic instrumentation: sources and detectors Measurement cells Q-factor and its measurement Good practices in RF and MW dielectric measurements 429

12 Contents xv 18.9 A survey of measurement methods Admittance methods in general and two- and three-terminal admittance cells Resonant admittance cells and their derivatives TEoi-mode cavities Split-post dielectric resonators Substrate methods, including ring resonators Coaxial and waveguide transmission lines Coaxial probes, waveguide and other dielectric probes Dielectric resonators Free-field methods The resonator perturbation technique Open-resonators Time domain techniques How should one choose the best measurement technique? Further information 449 References ' Calibration of ELF to UHF wire antennas, primarily for EMC testing 459 M. J. Alexander 19.1 Introduction Traceability of E-field strength High feed impedance half wave dipole Three-antenna method Calculability of coupling between two resonant dipole antennas Calculable field in a transverse electromagnetic (TEM) cell Uncertainty budget for EMC-radiated E-field emission Antenna factors Measurement of free-space AFs The calculable dipole antenna Calibration of biconical antennas in the frequency range MHz Calibration of LPDA antennas in the frequency range 200 MHz to 5 GHz Calibration of hybrid antennas Calibration of rod antennas Calibration of loop antennas Other antenna characteristics 468

13 xvi Contents 19.4 Electro-optic sensors and traceability of fields in TEM cells 469 Acknowledgements 470 References 470 Index 473