RF and Microwave Engineering
Description
A comprehensive guide to the fundamentals of radio frequency (RF), microwave engineering, and the physical aspects of wireless communications.
Combining physical-technical fundamentals with numerical simulations, RF and Microwave Engineering presents a wide range of RF topics with emphasis on physical aspects such as electromagnetic (EM) and voltage waves, transmission lines, passive circuits, and antennas. The text discusses the propagation of waves and their representation, effects, and utilization in passive circuits and antenna structures, incorporates various design examples using circuit and EM simulation software, and gives examples of modern RF tools to show how methods can be applied productively in RF engineering practice.
This revised edition includes new chapters on monostatic and bistatic radar cross sections (RCS), horn antennas, 5G mobile communications, substrate-integrated-waveguides (SIW), slot antennas, characteristics of resonators, and other topics.
A list of practice problems is provided at the end of each chapter and a companion website hosts solutions to the problem sets.
Written by a highly qualified professor this is the English language translation of the German original. RF and Microwave Engineering includes:
- Transmission line theory and transient signals on lines, covering characteristic line impedances, voltage waves, idealized lossless lines and cables with low losses, impedance transformation, reflection coefficient, and Smith chart diagram
- Waveguides, covering coaxial lines, including weak losses, parallel wire lines, microstrip lines, rectangular waveguides, substrate-integrated-waveguides, and three-wire systems
- Scattering parameters, covering multiport equations in matrix form, special network properties of circuits, and the signal flow method
- High-frequency components and circuits, covering line filters, couplers, power dividers, and matching circuits
- Antenna concepts and radio wave propagation in complex environments
RF and Microwave Engineering is an essential text for undergraduate and graduate students in electrical engineering courses including microwave engineering, basic circuit theory, electromagnetic fields, and wireless communications as well as early-stage RF practitioners and engineers.
Frank Gustrau has been a Professor at the University of Applied Sciences and Arts in Dortmund, Germany since 2003. Throughout his career in industry and academia, Professor Gustrau has supervised students in their project work, given lectures on different RF related topics, and worked extensively with EM and RF circuit simulation tools.
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Content
Preface x
Symbols and Abbreviations xii
About the Companion Website xvi
1 Introduction 1
1.1 Radiofrequency and Microwave Applications 1
1.2 Frequency Bands 4
1.3 Physical Phenomena in the High Frequency Domain 5
1.3.1 Electrically Short Transmission Line 5
1.3.2 Transmission Line with Length Greater Than One-Tenth of Wavelength 7
1.3.3 Radiation and Antennas 8
1.4 Outline of the Following Chapters 9
References 10
2 Electromagnetic Fields and Waves 11
2.1 Physical and Mathematical Basics 11
2.1.1 Electrostatic Fields 11
2.1.2 Steady Electric Current and Magnetic Fields 18
2.1.3 Differential Vector Operations 23
2.2 Maxwell's Equations 24
2.2.1 Differential Form in the Time Domain 24
2.2.2 Differential Form for Harmonic Time Dependence 25
2.2.3 Integral Form 26
2.2.4 Constitutive Relations and Material Properties 28
2.2.5 Boundary Conditions 31
2.3 Classification of Electromagnetic Problems 32
2.3.1 Static Fields 32
2.3.2 Quasi-Static Fields 33
2.3.3 Coupled Electromagnetic Fields 33
2.4 Skin Effect 33
2.5 Electromagnetic Waves 36
2.5.1 Wave Equation and Plane Waves 36
2.5.2 Polarization of Waves 40
2.5.3 Reflection and Refraction 42
2.5.4 Spherical Waves 48
2.6 Summary 50
2.7 Problems 51
References 52
Further Readings 52
3 Transmission Line Theory and Transient Signals on Lines 55
3.1 Transmission Line Theory 55
3.2 Transient Signals on Transmission Lines 84
3.3 Eye Diagram 94
3.4 Summary 95
3.5 Problems 97
References 98
Further Readings 98
4 Transmission Lines and Waveguides 99
4.1 Overview 99
4.2 Coaxial Line 102
4.3 Two-Wire Line 108
4.3.1 Characteristic Line Impedance 109
4.3.2 Areas of Application 109
4.4 Microstrip Line 1104.
4.1 Characteristic Line Impedance and Effective Permittivity 110
4.4.2 Dispersion and Technical Frequency Range 113
4.4.3 Areas of Application 114
4.5 Stripline 114
4.5.1 Characteristic Line Impedance 114
4.5.2 Technical Frequency Range 115
4.5.3 Areas of Application 115
4.6 Rectangular Waveguide 115
4.6.1 General Considerations 116
4.6.2 Dominant Mode 119
4.6.3 Higher Order Modes 122
4.6.4 Areas of Application 123
4.6.5 Excitation of Waveguide Modes 125
4.6.6 Cavity Resonators 126
4.7 Substrate-Integrated Waveguide (SIW) 128
4.7.1 Geometrical Structure and Electrical Characteristics 128
4.7.2 Microstrip-to-SIW Transition 131
4.8 Three-Conductor Transmission Line 131
4.8.1 Even and Odd Modes 131
4.8.2 Characteristic Line Impedances and Propagation Constants 135
4.8.3 Line Termination for Even and Odd Modes 136
4.9 Problems 137
References 138
5 Scattering Parameters 139
5.1 Multi-Port Network Representations 139
5.2 Normalized Power Waves 141
5.3 Scattering Parameters and Power 142
5.4 S-Parameter Representation of Network Properties 145
5.4.1 Matching 145
5.4.2 Complex Conjugate Matching 146
5.4.3 Reciprocity 148
5.4.4 Symmetry 148
5.4.5 Passive and Lossless Circuits 148
5.4.6 Unilateral Circuits 149
5.4.7 Specific Characteristics of Three-Port Networks 149
5.5 Calculation of S-Parameters 150
5.5.1 Reflection Coefficients 150
5.5.2 Transmission Coefficients 150
5.5.3 Renormalization 153
5.6 Signal Flow Method 154
5.6.1 Source 156
5.6.2 One-port Network/Load Termination 156
5.6.3 Two-port Network 156
5.6.4 Three-port Network 157
5.6.5 Four-port Network 157
5.7 S-Parameter Measurement 160
5.8 Problems 164
References 166
Further Readings 166
6 RF Components and Circuits 167
6.1 Equivalent Circuits of Concentrated Passive Components 167
6.1.1 Resistor 167
6.1.2 Capacitor 169
6.1.3 Inductor 170
6.2 Transmission Line Resonator 172
6.2.1 Half-Wave Resonator 172
6.2.2 Quarter-Wave Resonator 174
6.3 Impedance Matching 175
6.3.1 LC-Networks 176
6.3.2 Matching Using Distributed Elements 178
6.4 LC-Filter 181
6.4.1 Classical LC-Filter Design 182
6.4.2 Butterworth Filter 184
6.5 Transmission Line Filter 190
6.5.1 Edge-Coupled Line Filters 191
6.5.2 Hairpin Filter 195
6.5.3 Stepped Impedance Filter 195
6.5.4 Parasitic Box Resonance 195
6.5.5 Waveguide Filter 198
6.6 Circulator 200
6.7 Power Divider 201
6.7.1 Wilkinson Power Divider 201
6.7.2 Unequal Split Power Divider 202
6.8 Branchline Coupler 204
6.8.1 Conventional 3 dB Coupler 204
6.8.2 Unequal Split Branchline Coupler 206
6.9 Rat Race Coupler 208
6.10 Directional Coupler 210
6.11 Balanced-to-Unbalanced Circuits 212
6.12 Electronic Circuits 213
6.12.1 Mixers 215
6.12.2 Amplifiers and Oscillators 217
6.13 RF Design Software 218
6.13.1 RF Circuit Simulators 218
6.13.2 Three-Dimensional Electromagnetic Simulators 219
6.14 Problems 222
References 223
7 Antennas 225
7.1 Fundamental Parameters 225
7.1.1 Antennas as Wave-Type Converters 225
7.1.2 Nearfield and Farfield 225
7.1.3 Isotropic Radiator 227
7.1.4 Radiation Pattern and Related Parameters 228
7.1.5 Impedance Matching and Bandwidth 233
7.2 Standard Types of Antennas 234
7.3 Mathematical Treatment of the Hertzian Dipole 237
7.4 Wire Antennas 241
7.4.1 Half-Wave Dipole 241
7.4.2 Monopole 244
7.4.3 Concepts for Reducing Antenna Height 245
7.5 Slot Antennas 246
7.6 Aperture Radiators and Horn Antennas 248
7.6.1 Aperture Radiators 248
7.6.2 Horn Antennas 251
7.7 Planar Antennas 252
7.7.1 Rectangular Patch Antenna 253
7.7.2 Circularly Polarizing Patch Antennas 257
7.7.3 Planar Dipole and Inverted-F Antenna 260
7.8 Antenna Arrays 261
7.8.1 Single Element Radiation Pattern and Array Factor 261
7.8.2 Phased Array Antennas 264
7.8.3 Beam Forming 271
7.9 Modern Antenna Concepts 275
7.10 Problems 276
References 277
8 Radio Wave Propagation 279
8.1 Propagation Mechanisms 279
8.1.1 Reflection and Refraction 279
8.1.2 Absorption 279
8.1.3 Diffraction 280
8.1.4 Scattering 282
8.2 Basic Propagation Models 284
8.2.1 Free Space Loss 284
8.2.2 Attenuation of Air 286
8.2.3 Reflection at Scattering Targets (Radar Cross-Section) 287
8.2.4 Doppler Effect 294
8.2.5 Plane Earth Loss 296
8.2.6 Point-to-Point Radio Links 299
8.2.7 Layered Media 301
8.3 Path Loss Models 303
8.3.1 Multipath Environment 304
8.3.2 Clutter Factor Model 306
8.3.3 Okumura-Hata Model 306
8.3.4 Physical Models and Numerical Methods 307
8.4 Summary 310
8.5 Problems 311
References 311
A Mathematical Relations and Resonant Circuits 313
A.1 Coordinate Systems 313
A.1.1 Cartesian Coordinate System 313
A.1.2 Cylindrical Coordinate System 314
A.1.3 Spherical Coordinate System 315
A.2 Characteristics of Resonant Circuits 316
A.2.1 Series Resonant Circuit 316
A.2 Parallel Resonant Circuit 321
A.3 Logarithmic Representation 326
A.3.1 Dimensionless Quantities 326
A.3.2 Relative and Absolute Ratios 326
A.3 Link Budget 327
Index 329
1
Introduction
1.1 Radiofrequency and Microwave Applications
Today at home or on the move, every one of us uses devices that employ wireless technology to an increasing extent. Figure 1.1a shows a selection of wireless communication, navigation, identification and detection applications.
In the future we will see a growing progression of the trend to apply components and systems of high-frequency technology in new areas of application. Development and maintenance of such systems requires an extensive knowledge of high-frequency behavior of basic elements (e.g. resistors, capacitors, inductors, transmission lines, transistors), components (e.g. antennas), circuits (e.g. filters, amplifiers, mixers) including physical issues such as electromagnetic wave propagation (Figure 1.1b).
Table 1.1 shows a number of standard RF and microwave applications and their associated frequency bands [1-3]. The applications include terrestrial voice and data communication, which means cellular networks and wireless communication networks, as well as terrestrial and satellite-based broadcasting systems. Wireless identification systems (RFID) within industrial, scientific, and medical (ISM) bands enjoy increasing popularity among cargo traffic and logistics businesses. As for the field of navigation, GPS should be pointed out, which today is already installed in numerous vehicles and mobile devices. Looking at the automotive sector, radar systems are being used to monitor the surrounding area or serve as sensors for driver assistance systems.
The various application areas are developing rapidly. Let's take a look at the development of mobile telephony as an example. In the early days of mobile telephony, the focus was on voice communication. Analog terminals were bulky and expensive. With the second generation (2G/GSM), digital technology was introduced to mobile telephony in the 1990s. Terminals became more compact and affordable for the masses. In addition to voice communication, a text service or short message service (SMS) was established. At the turn of the millennium, the third generation (3G/UMTS) saw the development of mobile broadband applications with the possibility of using multimedia content (photo, video, music) and the Internet on the move. Under the influence of the new technical possibilities, the operating concepts of the end devices changed (touchscreen instead of the keyboard) and the equipment of the devices became more complex (e.g. built-in cameras).
Figure 1.1 (a) Examples of wireless applications and (b) RF components and propagation of electromagnetic waves.
With the fourth-generation mobile communications standard (4G/LTE-Advanced1) from around 2010, mobile broadband access was further developed, data rates were increased and capacity (number of simultaneously active subscribers in the network) was increased. Inexpensive devices and tariffs led to mobile broadband access for everyone. In addition to fast mobile broadband access, an expansion of the LTE standard (NB-IoT2) also included applications in the area of Industry 4.0 and the Internet of Things. The data rates in this field of application are comparatively low, but the requirements for energy efficiency and reliability are very high.
A fifth-generation mobile communications standard (5G) is currently being established in order to meet increasing requirements and open up further fields of application for mobile communications [4, 5]. A total of three application scenarios are being addressed:
- Improvements in mobile broadband applications (eMBB = enhanced Mobile Broadband): Higher data rates and reduced delay rates for VR3 and AR4 applications, among others.
- Communication between a large number of low-cost and energy-efficient devices for industrial applications (mMTC = massive Machine Type Communications).
- Applications with low latency and high reliability for autonomous driving, for example (URLLC = Ultra Reliable Low Latency Communications).
Table 1.1 Wireless applications and frequency ranges
Cellular mobile telephony GSM Global System for Mobile Communication 900 MHz, 1800 MHz (2nd generation mobile communication standard) UMTS Universal Mobile Telecommunications System 2100 MHz (3rd generation mobile communication standard) LTE Long Term Evolution 800 MHz, 1800 MHz, 2600 MHz (4th generation mobile communication standard) 5G 5th generation mobile communication standard 700 MHz, 3400 3800 MHz, ((*) Other frequency ranges planned) 28 GHz (*) Tetra Trunked radio 450 MHz Wireless networks WLAN Wireless local area network 2.45 GHz, 5 GHz Bluetooth Short range radio 2.45 GHz Navigation GPS Global Positioning System 1.2 GHz, 1.575 GHz Identification RFID Radio-Frequency Identification 13.56 MHz, 868 MHz, 2.45 GHz, 5 GHz Radio broadcasting FM Analog broadcast transmitter network MHz DAB Digital Audio Broadcasting 200 MHz DVB-T2 Digital Video Broadcasting - Terrestrial MHz DVB-S Digital Video Broadcasting - Satellite GHz Radar applications SRR Automotive short range radar 24 GHz ACC Adaptive cruise control radar 77 GHzSignificant changes have been made to the radio interface, among other things, in order to meet the requirements of the various application scenarios. All previous standards operated in the frequency range below 3 GHz (Table 1.1). The radio interface of the fifth generation of mobile communications (5G NR = 5G New Radio) distinguishes between the frequency range FR1 (Frequency Range 1) below 6 GHz and the frequency range FR2 (Frequency Range 2) above 24.25 GHz. The low frequencies (e.g. 700 MHz) are suitable for good network coverage in the area and for coverage in critical building areas (e.g. basements). In the 3-4 GHz range, propagation conditions are similar to those of the previous standards. The newly added millimeter wave range (e.g. 28 GHz) allows very high data rates and a very high capacity in small spatial areas. Multi-antenna concepts with beamforming can be realized at high frequencies with the help of very compact antenna systems. Overall, the development in the field of mobile radio is not foreseeable. In this book, we will lay the physical-technical foundations for understanding the high-frequency technical aspects of the various radio technologies and, for example, discuss antenna technology and wave propagation on lines, in circuits and in complex spatial environments.
However, high-frequency technology does not only play a decisive role in radio technology. Due to the increasing processing speed of digital circuits, high-frequency signal components are emerging, which means that high-frequency engineering design methods are also used for fast digital circuits.
Due to its proximity to electromagnetic field theory, high-frequency technology also extends into the field of electromagnetic compatibility.5 On the one hand, the measurement setups used here with cables and antennas are based directly on high-frequency principles. On the other hand, non-compliance with specified EMC limits generally requires a detailed analysis of the situation in order to achieve improvements. The inclusion of high-frequency aspects often leads to significant progress.
1.2 Frequency Bands
For better orientation, the electromagnetic spectrum is divided into a number of frequency bands. Various naming conventions have been established in different parts of the world, which often are used in parallel. Table 1.2 shows a customary classification of the frequency range from 3 kHz to 300 GHz into eight frequency decades according to a recommendation of the International Telecommunications Union (ITU) [6].
Figure 1.2a shows commonly used designation of different frequency bands according to...
