A Ka band CMOS differential LNA with 25dB gain using neutralized bootstrapped cascode amplifier

This paper presents a Ka band two-stage differential LNA in standard CMOS technology. Neutralized bootstrapped cascode amplifier (NBCA) is implemented to improve the gain and noise performance of the LNA while maintaining the stability. By using 1: 3 transformer and larger common gate transistor in the output buffer, the output matching is improved. The effects of neutralization and bootstrapped capacitor on the noise figure, gain and stability are further analyzed. Measurements show that the whole circuit offers a 25 dB peak gain and 4.1 dB NF at 34.5 GHz, with better than 10 dB return losses at the frequency band of interest (33.5 GHz-36 GHz).