Using capacitive cross-coupling technique in RF low noise amplifiers and down-conversion mixer design

We report an approach to improve the noise performance of RF low noise amplifiers (LNAs) and down-conversion mixers. The technique we described here is based on capacitive cross-coupling across the two sides of a differential input stage. A LNA and mixer have been implemented in 0.5µ CMOS process to demonstrate the viability of this technique. The measurements show that the LNA achieves 3.0dB noise figure and 12.2 dB voltage gain (optimized for the maximum power transfer), and the mixer has 5.2dB DSB noise figure and 13.2 dB voltage conversion gain. Both LNA and mixer operate at 2.7V voltage supply and consume 27mW and 8.1mW power, respectively.