Volume 3 is devoted to electromagnetic analysis and applications of antennas, antenna arrays, and microwave devices. It is designed to help the reader to get an insight into some modelling and simulation techniques as well as state of the art in wireless communication technologies. In Chapter 1, the finite element method (FEM) for wave propagation problems is presented. Special attention is paid to stability problems of different formulations in the low-frequency range. Chapter 2 deals with the Partial Element Equivalent Circuit (PEEC) method — a volume integral equation technique. In the framework of that method, a dual-grid scheme is introduced, which facilitates the treatment of electric and magnetic materials. Chapter 3 contains a high-level review of metamaterials and metasurfaces. Such materials have found their application in antenna design. In addition to a general introduction to the topic, the reader should get an understanding of the broad range of potential applications of these materials. Chapter 4 is also dedicated to metamaterials, especially to their application to electrically small directional antennas, ultra-wideband antennas with band-notches and high-density antenna arrays with reduced inter-element coupling. Chapter 5 is devoted to the so-called rectifying antennas, important for energy supply of wireless sensor nodes. The development process utilizing open-source tools is highlighted. In Chapter 6, the relatively new technologies — Radio Frequency Identification (RFID) and Near Field Communication (NFC) — are discussed. In addition to a historical review of these technologies, both theoretical fundamentals and simulation-based analysis and synthesis of loop antennas for these technologies are presented. An extension of the RFID technology to the so-called backscatter systems is presented in Chapter 7. Here, special attention is paid to the design parameters essential for reliable communication between the RFID tag and the reader. Chapter 8 is dedicated to topology optimization of antenna structures. An introduction to this subject area is given, and the applicability of topology optimization is demonstrated on important realistic problems. Inverse problems of electromagnetic scattering are discussed in Chapter 9. A method is introduced to determine material parameters of a scatterer meeting the constraints on the scattered field. Finally, in Chapter 10 a pseudo-analytical method for cylindrically symmetric electromagnetic structures is introduced, which enables, e.g. computationally inexpensive modelling of special sensors.