Antennas. Yi Huang

      Prof Yi Huang received BSc in Physics (Wuhan, China) in 1984, MSc (Eng) in Microwave Engineering (Nanjing, China) in 1987, and DPhil in Communications from the University of Oxford, United Kingdom, in 1994. He has been conducting research in the areas of antennas, wireless communications, applied electromagnetics, and radar since 1987. More recently, he is focused on mobile antennas, wireless energy harvesting, and power transfer. His experience includes three years spent with NRIET (China) as a Radar Engineer and various periods with the Universities of Birmingham, Oxford, and Essex in the United Kingdom as a member of research staff. He worked as a Research Fellow at British Telecom Labs in 1994 and then joined the Department of Electrical Engineering & Electronics, the University of Liverpool, United Kingdom, as a Faculty in 1995, where he is now a Chair Professor in Wireless Engineering, the Head of High Frequency Engineering Group.

      Dr Huang has published over 400 refereed papers in leading international journals and conference proceedings and authored three books. He has received many patents, research grants from research councils, government agencies, charity, EU, and industry and is a recipient of over 10 awards (e.g. BAE Systems Chairman’s Award 2017 for Innovation for Next Generation GNSS Antenna, Highly Recommended IET Innovation Award 2018, and Best Paper Awards). He has served on a number of national and international technical committees and been an Editor, Associate Editor, or Guest Editor of five international journals. In addition, he has been a keynote/invited speaker and organizer of many conferences and workshops (e.g. IEEE iWAT2010, LAPC2012, and EuCAP2018). He is at present the Editor‐in‐Chief of Wireless Engineering and Technology, Associate Editor of IEEE Antennas and Wireless Propagation Letters, United Kingdom, and Ireland Rep to European Association of Antenna and Propagation (EurAAP), a Fellow of IET and IEEE, and Senior Fellow of HEA.

      More information about him can be found from:

       https://www.liverpool.ac.uk/electrical‐engineering‐and‐electronics/staff/yi‐huang/

      About the Companion Website

      Antennas: From Theory to Practice, Second Edition is accompanied by a companion website:

      www.wiley.com//legacy/wileychi/huang_antennas2e/

      The website includes:

       Lecture PowerPoint Slides

       Answers to questions

1 Introduction

      1.1 A Brief History of Antennas

Work on antennas started many years ago. The first well‐known satisfactory antenna experiment was conducted by the German physicist Heinrich Rudolf Hertz (1857–1894), pictured in Figure 1.1. The SI (International Standard) frequency unit, Hertz, is named after him. In 1888, he built a system, as shown in Figure 1.2, to produce and detect radio waves. The original intention of his experiment was to demonstrate the existence of electromagnetic radiation. In the transmitter, a variable voltage source was connected to a dipole (a pair of 1 m wires) with two conducting balls (capacity spheres) at the ends.

Figure 1.1 Heinrich Rudolf Hertz

Figure 1.2 1887 experimental setup of Hertz's apparatus

      The gap between the balls could be adjusted for circuit resonance as well as for the generation of sparks. When the voltage was increased to a certain value, a spark or break‐down discharge was produced. The receiver was a simple loop with two identical conducting balls. The gap between the balls was carefully tuned to receive the spark effectively. He placed the apparatus in a darkened box to see the spark clearly. In his experiment, when a spark was generated at the transmitter, he also observed a spark at the receiver gap at almost the same time. This proved that the information from location A (the transmitter) was transmitted to location B (the receiver) in a wireless manner – electromagnetic (EM) waves! The information in his experiment was actually in binary digital form by tuning the spark on and off. This could be considered as the very first digital wireless system that consisted of two of the best‐known antennas: the dipole and the loop. For this reason, the dipole antenna is also called Hertz (dipole) antenna (Figure 1.2).

While Heinrich Hertz conducted his experiments in a laboratory and did not quite know what radio waves might be used for in practice, Guglielmo Marconi (1874–1937, pictured in Figure 1.3), an Italian inventor, was the man who developed and commercialized wireless technology by introducing a radiotelegraph system, which served as the foundation for the establishment of numerous affiliated companies worldwide. His most famous experiment was the transatlantic transmission from Poldhu, UK, to St Johns, Newfoundland, in the USA in 1901 employing un‐tuned systems. He shared the 1909 Nobel Prize in Physics with Karl Ferdinand Braun ‘in recognition of their contributions to the development of wireless telegraphy’. Monopole antennas (near quarter wavelength) were widely used in his experiments, thus vertical monopole antennas are also called Marconi antennas.

Figure 1.3 Guglielmo Marconi.

      Source: https://commons.wikimedia.org/wiki/File:Marconi_1909.jpg#/media/File:Marconi_1909.jpg

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