A mixer-first receiver with enhanced selectivity by capacitive positive feedback achieving +39dBm IIP3 and <3dB noise figure for SAW-less LTE Radio

A mixer-first receiver enhanced with capacitive positive feedback is proposed to obtain a steeper filter roll-off and enhanced linearity, while keeping low noise figure. It covers all sub-6GHz cellular bands and achieves a high IIP3 of +39dBm and blocker 1dB gain compression point of +12dBm for a blocker frequency-offset of 80MHz at f
_LO
=2GHz. The NF ranges from 2.4dB at f
_LO
=1GHz to 5.4dB at f
_LO
=6GHz. The chip has been fabricated in Globalfoundries 45nm SOI technology on a high resistivity substrate.