Integrated Blocker Filtering RF Front Ends

This paper presents integrated blocker filtering RF front-ends (BF-RF). In wireless cellular systems the blockers are from either self transmitters, such as WCDMA or form the other users´ transmitters such as GSM. The proposed blocker filtering deploys the concept of blocker injection through feedforward or feedback paths to create arbitrary narrowband notches for the out-of-band blockers, while not affecting the gain of the desired signal. The BF-RF obviates the use of the off-chip SAW filters. Fabricated in a 0.18 mum CMOS technology the prototype achieves a 50 dB of signal to blocker ratio. The receiver path draws 24 from a 1.8 V voltage supply, and the blocker filtering path adds on average only 2 mA to the total power consumption. The die area is 1.5times1.2 mm².