Broadband Reflectometry for Enhanced Diagnostics and Monitoring Applications (eBook)

Preface 8
Contents 11
Introduction 16
The Concept Behind This Book 16
Survey of Typical Applications of BMR 18
Electrical Components Characterization: Testing and Localization of Faults 18
Measurements on Soil for Agricultural and Geotechnical Purposes 19
Civil Engineering and Infrastructural Monitoring 19
Dielectric Spectroscopy Measurements 20
Applications in Industrial Monitoring 20
Organization and Content of the Book 20
References 22
Basic Physical Principles 25
Transmission Line Basics 25
Coaxial Transmission Line 26
Bifilar Transmission Line 28
Microstrip Line 28
Reflected Waves 29
Characteristic Parameters of Electrical Networks 30
Reflectometry Measurements for Dielectric Spectroscopy 33
Dielectric Relaxation Models 34
References 37
Broadband Reflectometry: Theoretical Background 39
Broadband Microwave Reflectometry: Theoretical Background 39
Time Domain Reflectometry (TDR) 40
Typical TDR Measurements 43
Typical TDR Instrumentation 44
Frequency Domain Reflectometry (FDR) 47
TD/FD Combined Approach 49
Preserving Measurement Accuracy in the TDR/FDR Transformation 50
The Sensing Element 51
Strategies for Enhancing Accuracy in BMR Measurements 55
Calibration Procedure in Time Domain 55
Calibration Procedure in Frequency Domain 56
Time-gated Frequency Domain Approach 57
Transmission Line Modeling and Inverse Modeling 58
References 61
Quantitative and Qualitative Characterization of Liquid Materials 64
Introduction 64
Estimation of Levels and Permittivities of Industrial Liquids Directly from TDR 66
Probe Design and Realization 67
Sources of Errors and Compensation Strategies in TD 69
Validation of the Method on Dielectric Liquids 71
Estimation of Levels and Permittivities of Industrial Liquids 73
Transmission Line Modeling of the Measurement Cell 74
Measurement Setup and Enhanced Probe Design 75
Experimental Validation of the Method 77
Dielectric Spectroscopy of Edible Liquids: The Vegetable Oils Case-Study 84
Design of the Measurement Cell and Transmission Line Modeling 85
Experimental Results for Vegetable Oils 90
References 95
Qualitative Characterization of Granular Materials and Moisture Measurements 97
Introduction 97
Dielectric Models for the Estimation of Water Content 99
Evaluation of Moisture Content Directly from TDR 101
Details on the Experimental Procedure 102
Uncertainty Evaluation for Apparent Dielectric Permittivity Measurement and Individuation of the Calibration Curves 103
Measurement Results and Instrumental Performance Comparison 105
Moisture Content Measurements through TD/FD Combined Approach 109
Moisture Content Measurements through Dielectric Mixing Model 109
Triple-Short Calibration Procedure 110
Enhancements of TDR-Based Static Electrical Conductivity Measurement 119
Traditional TDR-Based Static Electrical Conductivity Measurement 120
Innovative Calibration Strategies: The TLM and the ICM Methods 122
Validation of the Methods 127
Practical Considerations 131
Noninvasive Moisture Content Measurements 131
Basic Theory of Microstrip Antennas 132
Experimental Validation of the Method: Measurements on Moistened Sand Samples 134
References 140
BMR Characterization of Antennas through the Combined TD/FD Approach 144
Introduction 144
Measurement Setup for the Validation of the Method 145
Acquisition in Time Domain 146
RFId Antenna Results 148
Practical Guidelines for Retrieving Accurate Measurements 149
Biconical Antenna Results 156
References 158