Gigahertz and Terahertz Technologies for Broadband Communications, Second Edition is a cutting-edge resource for understanding current, emerging, and future broadband communications systems, as well as the industry's major players and their products. Nowadays, our powerful mobile phones are the center of our digital lives, and this depends on gigahertz and terahertz technologies for broadband communications. This second edition covers more material on the massive and radical technological developments that have occurred in the past two decades.With the world becoming more digitalized, particularly with the rise of remote work, video conferencing, and devices such as gaming systems, there is an increase in the utilization of broadband communication technologies. This includes broadband fiber-optics (cable), free-space optics (FSO), mmWave terrestrial radio links, high-altitude platform services (HAPS), and satellite communications (SATCOM). The second edition of this resource covers the key aspects and provides numerous examples of these communication technologies.This second edition provides engineers with the necessary tools to navigate the complexities of designing communication systems for 5G, 6G, terrestrial, space, and satellite applications. In summary, it serves as an indispensable guide for professionals seeking to stay informed of the latest advancements in broadband communication technologies. This is a great resource for a skilled engineer or a newcomer to the field, it provides valuable insights and practical advice to navigate the challenges of modern communication systems.