The modules use both the RCWL-9616 and the BISS-0001 but it seems the schematics are all labeled BISS-0001. The parts values are different. He gives some good information about them. They operate at 3.5 and 3.98 GHz – the ones I have were advertised at 5 GHz. Also he shows his own version that uses a dual opamp.
http://www.ko4bb.com/getsimple/index.php?id=rcwl-0516-microwave-doppler-module
