This book presents innovation in MIMO communication wireless networks and antennas. The book comprehensively reviews massive MIMO systems, key technologies, challenges, and future directions. The book presents green RF technologies and systems for MIMO antenna systems. Moreover, the book presents innovation in massive MIMO cellular networks and antennas. The family of LML detectors and the family of LAS detectors for massive MIMO communications are presented in the book. Active shielding methods for space radiation protection are also presented in the book. This book evaluates massive MIMO performance with Rayleigh, Rician, and Nakagami fading channels and compares half-duplex and full-duplex modes using the HMR protocol. MIMO antenna arrays and sparse polarimetric arrays for MIMO systems are discussed in the book. In MIMO antenna networks, multiple antennas are used to transmit and receive elements. The antenna’s electromagnetic signals are combined at each port of the RF communication system to improve the communication system specifications and improve the system’s electrical performance by enabling data to be processed in real-time over many signal RF channels. MIMO systems provide better signal strength even without a clear line of sight as they utilize the bounced and reflected RF transmissions. MIMO systems provide better quality and quantity of video information sent over the network. Multiple data links minimize the number of lost data packets, which results in better video and audio quality. The book may be a valuable resource for MIMO antenna designers, academy researchers, communication engineers, and communication systems project managers involved in developing and manufacturing MIMO arrays and communication systems. The information presented aims to inspire further innovation and application in this field.