This book provides a simple explanation of existing antenna arrays, their advances and limitations. It will lead you to nature-inspired next generation antenna array design and their advances. Why antenna arrays? Because antennas or antenna arrays are the primary element in any sensory system or circuit. Any artificial intellect, computer, vision, communication, or detection system cannot work properly without a properly designed sensor system or antenna array. They include not only technical areas like communication, navigation and radars, but also health care, medical imaging and even amateur metal detectors and RC vehicle design. The purpose of this book is to provide a comprehensive and accessible explanation of antenna arrays, their advancements, and their limitations. By exploring the principles of antenna arrays and their applications, readers will gain a deeper understanding of their design and potential advancements inspired by nature. Antennas and antenna arrays play a crucial role in sensory systems and circuits, serving as the primary components for various technologies. Without well-designed sensor systems or antenna arrays, it is challenging for Artifcial Intelligence, computers, vision systems, communication systems, and detection systems to operate effectively.