Radar is kind of fun to get into, though 2 Ghz isn't a very good frequency for (through-wall) imaging. http://ocw.mit.edu/resources/res-ll-003-build-a-small-rad

Radar is kind of fun to get into, though 2 Ghz isn't a very good frequency for (through-wall) imaging. http://ocw.mit.edu/resources/res-ll-003-build-a-small-radar-system-capable-of-sensing-range-doppler-and-synthetic-aperture-radar-imaging-january-iap-2011/ http://ocw.mit.edu/resources/res-ll-003-build-a-small-radar-... has some SAR demos, and if you follow to Dr. Charvat's website you can see he made a 10 Ghz system that images through concrete walls very well.