Quad-flat no-lead (QFN) is one of the standard packaging technologies used in electronics. MMIC is wire bonded to a pre-produced lead frame. Then, whole package is molded on top with plastic. Having 0.4mm to 0.6mm pitch, it is easy to handle for surface mount technologies (SMT) for assembly printed circuit boards (PCB). For more detailed information: Wikipedia - QFN
Cheap and Reliable
Suitable for series production and series testing
Short RF bond wires are not possible
RF signal loss due to long bond wires for RF pads
RF signal loss over the molding material for on chip antenna versions
Since this technology is very well known and widely used around the globe, Silicon Radar is trying to keep its standard layouts even for other packaging technologies.