submitted this past spring.
This paper describes a S-band UWB rail SAR imaging radar system that
i developed using a discarded Genie garage door opener, some crystal
filters from a communications receiver, a bunch of surplus parts
combined with a Labview NI card. The results were surprisingly good,
especially considering the low-budget available to develop this system. See web article: http://www.mit.edu/~gr20603/Dr.%20Gregory%20L.%20Charvat%20Projects/Low-Power%20S-Band%20Rail%20SAR.html
If you find this sort of UWB S-band rail SAR stuff interesting then
stay tuned to IEEE APS Transactions.