Wireless communications are based on the launching‎,‎ propagation‎,‎ and detection of electromagnetic waves emitted primarily at radio or microwave frequencies‎.‎ Their history can be traced back to the mid‎-19th century when James Clerk Maxwell formulated the basic laws of electromagnetism and Heinrich Hertz demonstrated the propagation of radio waves across his laboratory‎.‎ Recent engineering breakthroughs have led to wireless communication systems that have not only revolutionized modern lifestyles‎,‎ but have also launched new industries‎.‎Based on the author‎'‎s course in the physics of wireless communications‎,‎ "Physical Principles of Wireless Communications" provides students with a solid foundation in modern wireless communication systems‎.‎ It offers rigorous analyses of the devices and physical mechanisms that constitute the physical layers of these systems‎.‎ Starting with a review of Maxwell‎'‎s equations‎,‎ the textbook details the operation of antennas and antenna arrays‎,‎ teaching students how to perform the necessary design calculations‎.‎ It also explores the propagation of electromagnetic waves‎,‎ leading to important descriptions of mean path loss‎.‎ The text also reviews the principles of probability theory‎,‎ enabling students to calculate the margins that must be allowed to account for statistical variation in path loss‎.‎In addition‎,‎ it covers the physics of Geostationary Earth Orbiting ‎(‎GEO‎)‎ satellites and Low Earth Orbiting ‎(‎LEO‎)‎ satellites so students may evaluate and make first‎-order designs of satellite communications ‎(‎SATCOM‎)‎ systems‎.‎