Reconfigurable MIMO antennas are presented in Chapter 7, which discusses the following: reconfigurable antennas for MIMO applications, isolation techniques in MIMO antennas, pattern diversity scheme, reconfigurable polarization MIMO antennas, MIMO antenna performance parameters, and finally some reconfigurable MIMO antenna examples. Chapter 8 offers discussion on the MIMO antennas in multifunctional systems, MIMO antennas in Radar systems, MIMO antennas in communication systems, MIMO antennas for sensing applications, MIMO antennas for 5G systems, massive MIMO arrays, dielectric lens for millimeter wave MIMO, beamforming in massive MIMO, MIMO in imaging systems, and MIMO antenna in medical applications. Use of metamaterials in reconfigurable antennas have been addressed in Chapter 9. This chapter focuses the discussion on metamaterials in antenna reconfigurability, metamaterial‐inspired reconfigurable antennas, and metasurface‐inspired reconfigurable antennas.
Chapter 10 provides detailed discussion on the multifunctional antennas for user equipments (UEs) with emphasis on the lower/sub‐6 GHz 5G band antennas, 5G mm‐wave antenna arrays, collocated sub‐6 GHz and mm‐Wave 5G array antennas, and RF and electromagnetic fields (EMF) exposure limits. The department of defense (DoD) related reconfigurable antennas are presented in Chapter 11 with a focus on the tactical air navigation system (TACAN) antennas, sea‐based X‐Band Radar 1 (SBX‐1) antennas, the advanced multifunction RF concept (AMRFC) antennas, integrated topside (InTop) antennas, the Defense Advanced Research Projects Agency (DARPA) arrays of commercial timescales (ACT), and the Air Force Research Laboratory (AFRL) transformational element level array (TELA). Finally, Chapter 12 discusses 5G silicon RFICs‐based phased array antennas, which introduces silicon beamformer technology. It includes a short discussion of three phase shifting topologies using local oscillator (LO) based phase shifting, intermediate frequency (IF) based phase shifting and RF based phase shifting for beam steering array antennas. Several flat panel phased array antenna examples using the silicon beamforming chipsets both at Ku‐ and Ka‐band with linear and circular polarizations are also presented.
We would like to mention that the slight overlap between the content in couple of chapters is acknowledged. We have done this intentionally so that discussion is complete in the respective chapters. While the contributors and authors have made great effort to present details for each topic area, they are by no means complete as the body of work in this field is large. They do represent the interpretations of each chapter’s contributors. As time progresses, further improvements and innovations in the state‐of‐the‐art technologies in reconfigurable antennas is anticipated. Therefore, it is expected that interested readers should continually refresh their knowledge to follow the growth of communication technologies.
Professor Satish K. Sharma, PhDJia‐Chi S. Chieh, PhD
1 February 2021
San Diego, CA, USA
Acknowledgements
We would like to offer our sincere thanks to the chapter coauthors for their valuable contributions, patience and timely support throughout the development of this book. We would also like to thank the Wiley team members especially, Brett Kurzman, Victoria Bradshaw, Sarah Lemore, Sukhwinder Singh and most importantly S. M. Amudhapriya for their immense help throughout the completion of this book.
Professor Satish K. Sharma will like to take this opportunity to thank his research collaborators, past and present graduate students, post‐doctoral fellows, visiting scholars, and undergraduate students at San Diego State University (SDSU) who have been the continuous source for his research growth. He thanks Dr. Jia‐Chi S. Chieh for agreeing to work on this book. He also thanks the funding agencies: National Science Foundation (NSF) for the prestigious CAREER award, the Office of Naval Research (ONR), the Naval Information Warfare Center‐Pacific (NIWC‐PAC), the Space and Naval Warfare Systems Command (SPAWAR)‐San Diego, and the SBIR/STTR Phase I and II research grants subcontracted through the local industries, which have helped him pursue his research work. Finally, he thanks his spouse Mamta Sharma (Author and Artist) and daughters Shiva Shree Sharma (Doctoral Student in Material Science Engineering at University of California, Riverside, California) and Shruti Shree Sharma (Undergraduate Student in Electrical Engineering at University of California, Irvine, California) who spared their valuable time to let him work on this book and offered their unconditional love and support as always. He also thanks his pet dog and cat Charlie Sharma and Razzle Sharma, respectively, for their unconditional love to him. Lastly, he is grateful to his parents (Mr. Rama Naresh Sharma and Mrs. Taravati Sharma), elders in his extended family, research advisors (Professors L. Shafai, the University of Manitoba and B. R. Vishvakarma, Indian Institute of Technology, Banaras Hindu University), teachers, colleagues, friends and the almighty God for bestowing continuous blessings on him.
Dr. Jia‐Chi S. Chieh is grateful to his research group at the Naval Information Warfare Center in San Diego for their tireless efforts in the development of low‐cost phased array antennas over the last decade. He is also grateful for the research collaboration opportunities he has had with Prof. Satish K. Sharma from San Diego State University (SDSU), as well as his mentorship and friendship over the years. He is thankful to his family for their love and support, and who have allowed him to complete this work including his wife Kristine, and his two daughters Joanna and Audrey. Lastly, he is grateful to his parents (Dr. Shih‐Huang Chieh and Mrs. Dolly Chieh), who taught him the importance of learning and to never stop.
Professor Satish K. Sharma, PhDJia‐Chi S. Chieh, PhD
1 February 2021
San Diego, CA, USA
1 Introduction
Satish K. Sharma and Jia‐Chi S. Chieh
1.1 Introduction
In this chapter, we provide basic discussion about an antenna and its importance, type of antennas, and introductory information about the reconfigurable antenna, frequency agile antenna, multifunctional antenna, and antenna measurements.
1.2 Antenna: an Integral Component of Wireless Communications
An antenna is described as a device that radiates or receives transverse electromagnetic waves (TEM) from its surface, or structure. It is an integral component of all the wireless communication systems. As shown in Figure 1.1, the transmitter block which usually consists of the signal generator, modulator, and power amplifiers is terminated with an antenna to radiate the power in free space. A poor choice and design of antenna will result in the power being reflected to the source and cause waste of power, which is undesirable. Efficient power utilization becomes critical in applications such as onboard circuits in satellite communications. To emphasize the importance of antennas for the receiver circuitry, maximum power should be obtained from the incident wave to relax the burden on the succeeding blocks such as low noise amplifiers to maintain the required signal‐to‐noise‐ratio (SNR) for satisfactory wireless links. Different communication application demands different minimum required SNR for a satisfactory link and efficient antenna design plays a big role in achieving this goal.
