Hunter Scott's talk from the 2018 Hackaday Superconference explains what phased arrays are, their basic architecture, their benefits, and how to make one yourself. He also talks about how we can take advantage of new chips for the coming 5G standard to reduce hardware cost and complexity.
Read the article on Hackaday:
http://hackaday.com/?p=339609
Slides Hunter's talk are available on his website:
https://www.hscott.net/phasedarray/
Visit for full list of talks and workshops : https://hackaday.io/superconference/