Dedicated to a new class of wideband antenna, significantly developed over the past two decades, this book is the ultimate reference on magnetoelectric dipole antennas. The author is world-renowned for his pioneering work on antennas and has continuously developed the magnetoelectric dipole antenna since 2006. With contributions from the author and his students as well as results from research groups worldwide, the development of this novel antenna is fully captured. The theory and design are presented step-by-step, using simple technical explanations, making the contents accessible to readers without specialized training in antenna designs. Including the various applications of the antenna such as communications, global positioning, sensing, radar, medical imaging, and IoT, this book endeavors to demonstrate the versatility and interdisciplinarity of the antennas.

Major techniques for enhancing the bandwidth of magnetoelectric (ME) dipoles available in the literature are reviewed and discussed. Designs with single-input port and differential input ports are reported. Hopefully, it can help the readers to appreciate the beauty of these interesting designs and inspire innovative designs for future applications.

In this chapter, techniques for size reduction of the magnetoelectric dipole available in the literature are reviewed. The relative advantages of employing the folded patch technique, dielectric-loaded method, and the metamaterial-loaded approach are compared. Designs with single-input port and differential input ports are also reviewed. Hopefully, possible new techniques will be achieved by readers after reviewing all these interesting designs.

The performance of the basic linearly polarized magnetoelectric dipole is reviewed in detail to prepare the readers to appreciate other sophisticated designs in the chapters to follow. A new equivalent circuit of the antenna is given, which is different from the previous one proposed in the literature. The current density distributions on the antenna surfaces are provided to help understand the operating principle of the magnetoelectric antenna. The effect of ground plane size and sidewall height on the radiation patterns is given. Finally, a design guideline is suggested.

Substantial amount of work on the development of ME dipoles has been published by the originator’s group and other researchers and scholars over the past decade. It is now the appropriate time to review those findings and put those useful designs into appropriate perspectives. After providing the necessary background in understanding the importance of the ME dipoles in this introductory chapter, the detailed design guideline and performance of various ME dipoles with different characteristics will be presented and discussed in the chapters to follow.

Various feeding techniques and antenna structures for achieving dual-polarized and circularly polarized ME dipoles will be reviewed. Since some circularly polarized ME dipoles can be developed from dual-polarized ME dipoles, these two classes of ME dipoles are considered and reviewed together here.

The development of linearly polarized magnetoelectric (ME) dipoles operated at lower microwave frequencies is reviewed. Magnetoelectric dipoles can be fabricated at low costs, as they are purely made of metal plates at a few GHz range. Designs with modified L-shaped probe feeds for various purposes are first presented. Magnetoelectric dipoles with modified dipole shapes and feeds for enabling the antennas to be d.c. grounded are summarized. The aperture coupling technique was widely applied for the designs of microstrip antennas. Magnetoelectric dipoles with aperture-coupled feeds were also proposed in the literature. Their characteristics are presented. Differentially fed ME dipoles are also reviewed. The performance of ME dipoles for MIMO systems is discussed, which is of topical interest for 5G applications. Some recent applications of linearly polarized ME dipoles in different array environments are also presented.

A comprehensive review on using different transmission lines for feeding ME dipole antennas and arrays is presented, including the SIW, ridge gap waveguide, packaged microstrip line, and substrate-integrated coaxial line feeds. In addition, the developments of low profile of ME dipole arrays, filtering ME dipoles, and all-metal ME dipole arrays for high-power applications are summarized. Some other recent applications are briefly reported. Hopefully, our readers can appreciate the attractiveness of the ME dipoles for future wireless applications at millimeter-wave and terahertz frequencies.

This chapter covers digital information sources in some depth. It provides intuition on the information content of a digital source and introduces the notion of redundancy. As a simple but important example, discrete memoryless sources are described. The concept of entropy is defined as a measure of the information content of a digital information source. The properties of entropy are studied, and the source-coding theorem for a discrete memoryless source is given. In the second part of the chapter, practical data compression algorithms are studied. Specifically, Huffman coding, which is an optimal data-compression algorithm when the source statistics are known, and Lempel–Ziv (LZ) and Lempel–Ziv–Welch (LZW) coding schemes, which are universal compression algorithms (not requiring the source statistics), are detailed.

The basics of digital modulation over additive white Gaussian noise (AWGN) channels are studied. To facilitate a formal study, the concepts of signal space and signal constellations are introduced. The Gram–Schmidt orthonormalization procedure, a systematic method to obtain an orthogonal and normalized basis for a given set of signals, is described. Binary antipodal signaling is studied in detail; the MAP and ML receivers are derived, and the average probability of error is computed. The concepts are then generalized to the case of M-ary signaling, and the union bound is introduced as a performance analysis tool. Correlation-type and matched filter-type receivers are described. The properties of the matched filter are summarized. Different signal constellations are compared in terms of their error rate performance through a simplified (asymptotic) analysis. As specific examples, the details of two important digital modulation schemes, pulse amplitude modulation and orthogonal signaling, are given. Finally, timing recovery techniques are briefly studied.