The authors present low-cost design solutions for smart antenna systems. This is very important as the realizations of 5G mobile communication, next-generation broadband satellite communications and Internet Of Things (IOT) have huge demands for smart antennas which have low cost, low power and compact size, which cannot be met by traditional smart antenna systems due to their high cost, high power consumption and bulky size. Up to date, there is no book addressing this topic, and case studies in each chapter will be helpful for people to understand the theory and technology better. Current literature focuses on signal processing algorithms – the software – of the antenna. This book is unique in focusing on the antenna hardware, and will cover fundamental theories and advanced topics, suitable for readers at varying levels of study and experience.