A GPS receiver depends on CMOS technology for both its GPS digital signal
processing (DSP) and radio frequency (RF) stages. A resulting increase in
RF input noise generated by the CMOS RF input is overcome by placing the
antenna on-chip or on a lid of an application specific integrated circuit
(ASIC) that includes the DSP and RF stages, and matching it for the best
noise figure rather than the best impedance match. The on-chip antenna is
matched to the natural high impedance of the CMOS RF input without
requiring matching networks that can attenuate already weak signals.
Using CMOS technology for both the GPS DSP and RF stages eliminates the
need for level shifts between what would otherwise be a 3-volt RF section
and a 1.2-volt DSP section.