[emusan]

If you're interested in the cantenna radar you might also find Henrik Forsten's radar interesting: https://hforsten.com/6-ghz-frequency-modulated-radar.html. It uses largely the same high-level design, but is a bit more integrated as a single unit (rather than a series of minicircuits components).

I've built the MIT radar before and it is a great way to learn the basics of radar!

In either design you can likely get away with <$500 worth of materials.

Henrik has follow-up blogs adding and modifying this design for more functionality, it's a pretty neat project to follow!

[thmsths]

Quick question regarding DYI radars. What's the legality of it? I would assume the radar frequency bands are reserved (I could not find much information on this with a quick google search). I wouldn't want to get a visit from the FCC because my hobby project is interfering with the nearby airport. In the project you linked he is using WiFi bands, but they come with their own restrictions (the very low power limits immediately comes to mind).