A CMOS LNA with Transformer-Based Integrated Notch Filter for Ku-Band Satellite Communications
Jiajun Zhang, Dixian Zhao, Xiaohu You
Abstract
A low-noise amplifier (LNA) for Ku-band satellite communications with transformer-based integrated notch filter is implemented in 65-nm CMOS. The notch filter is integrated in a 3-coil transformer in the matching network. While the primary coil and the secondary coil build a magnetically coupled resonator (MCR) and achieve wideband inter-stage matching, the tertiary coil is coupled with the primary coil to attenuate the interferers. The LNA exhibits a measured power gain of 19.5 dB at 12.2 GHz with a −3-dB bandwidth of 9.2-12.7 GHz. With Q- enhancement circuit, the LNA achieves up-to-50-dB gain suppression. The noise figure (NF) is 2.3 dB at 10.6 GHz and below 2.7 dB from 9.2 to 12.7 GHz. The input return loss is better than −15 dB from 8.8 to 18.5 GHz. The LNA consumes 5.9-6.5 mW from a 1-V supply.