Electromagnetic Measurements in the Near Field

by Bienkowski, Pawel; Trzaska, Hubert

• ISBN13: 9781891121067
• ISBN10: 1891121065
• Edition: 2nd
• Format: Hardcover
• Copyright: 2011-11-15
• Publisher: Scitech Pub Inc

Summary

SciTech Series on Electromagnetic Compatibility Alistair Duffy, PhD - Series Editor This book is devoted to the specific problems of electromagnetic field (EMF) measurements in the near field and to the analysis of the main factors which impede accuracy in these measurements. It focuses on careful and accurate design of systems to measure in the near field based on a thorough understanding of the fundamental engineering principles and on an analysis of the likely system errors. Beginning with a short introduction to electromagnetic fields with an emphasis on the near field, it then presents methods of EMF measurements in near field conditions. It details the factors limiting measurement accuracy including internal ones (thermal stability, frequency response, dynamic characteristics, susceptibility) and external ones (field integration, mutual couplings between a probe and primary and secondary EMF sources, directional pattern deformations). It continues with a discussion on how to gauge the parameters declared by an EMF meter manufacturer and simple methods for testing these parameters. It also details how designers of measuring equipment can reconsider the near field when designing and testing, as well as how users can exploit the knowledge within the book to ensure their tests and results contain the most accurate measurements possible. The SciTech Publishing Series on Electromagnetic Compatibility provides a continuously growing body of knowledge in the latest development and best practices in electromagnetic compatibility engineering. This series provides specialist and non-specialist professionals and students practical knowledge that is thoroughly grounded in relevant theory.

Author Biography

Pawel Bienkowski is affiliated with the EM Environment Protection Lab at the Technical University of Wroclaw, Poland where he researches electromagnetic compatibility and electromagnetic field measurements and standards. He is the author or co-author of over 100 publications and over 20 patents. Hubert Trzaska is a Professor in the EM Environment Protection Lab at the Technical University of Wroclaw, Poland where he researches electromagnetic field measurements and standards. He is a Charter Member of the Bioelectromagnetic Society and is the author or co-author of over 300 publications and over 50 patents.

Table of Contents

Preface	p. vii
Preface to the Second Edition	p. ix
Acknowledgments	p. xi
Introduction	p. 1
The Near Field and the Far Field	p. 11
An EMF Generated by a System of Currents	p. 11
The Far Field and the Near Field	p. 14
EMF from Simple Radiating Structures	p. 19
EMF Measurement Methods	p. 27
E, H, and S Measurement	p. 28
Temperature Rise Measurements	p. 33
SAR Measurement	p. 40
Current Measurements	p. 41
Electric Field Measurement	p. 51
Field Averaging by a Measuring Antenna	p. 52
Influence of Fields from beyond a Probe Measuring Band	p. 55
Mutual Interaction of the Measuring Antenna and the Field Source	p. 69
Changes in the Probes' Directional Pattern	p. 74
E-Field Probe Comparison	p. 80
Comments and Conclusions	p. 85
Magnetic Field Measurement	p. 89
The Sizes of the Measuring Antenna	p. 89
Frequency Response of the Magnetic Field Probe	p. 92
Directional Pattern Alternations	p. 95
Measurement Accuracy vs. Antenna Distance from Radiation Source	p. 100
Magnetic Field Probe with a Loop Working above Its Self-Resonant Frequency	p. 105
Comments and Conclusions	p. 109
Power Density Measurement	p. 113
Power Density Measurement Methods	p. 113
Power Density Measurement Using the Antenna Effect	p. 122
Conclusions and Comments	p. 128
Directional Pattern Synthesis	p. 133
A Probe Composed of Linearly Dependent Elements	p. 134
Spherical Radiation Pattern of an E/H Probe	p. 137
A Probe Composed of Three Mutually Perpendicular Dipoles	p. 140
Comments and Conclusions	p. 145
Other Factors Limiting Measurement Accuracy	p. 151
Thermal Stability of a Field Meter	p. 151
The Dynamic Characteristics of the Detector	p. 158
Measured Field Deformations	p. 164
Susceptibility of the Meter to External EMF	p. 167
Resonant Phenomena	p. 172
Human Factor	p. 175
Uncertainty Budget	p. 177
Photonic EMF Measurements	p. 183
The Photonic EMF Probe	p. 186
Frequency Response of the Probe	p. 190
Sensitivity of the Photonic Probe	p. 194
Magnetic Field Photonic Probe	p. 199
Detector Linearity	p. 200
Synthesis of the Spherical Directional Pattern	p. 201
The "Future Meter"	p. 203
Final Comments	p. 207
Index	p. 215
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