Book excerpt: Microwave and millimeter-wave (mm-wave) circuits and systems have been widely employed in various emerging technologies such as 5G and beyond wireless mobile communication systems, autonomous driving, electronic warfare, and radar systems. To better understand the benefits, challenges, and opportunities of this technology, further study is required. The Handbook of Research on Emerging Designs and Applications for Microwave and Millimeter Wave Circuits describes the latest advances in microwave and mm-wave applications and provides state-of-the-art research in the domain of microwave, mm-wave, and THz devices and systems. Covering key topics such as antennas, circuits, propagation, and energy harvesting, this major reference work is ideal for computer scientists, industry professionals, researchers, academicians, practitioners, scholars, instructors, and students.