A Concurrent Tri-Band Low-Noise Amplifier With a Novel Tri-Band Load Resonator Employing Feedback Notches

A concurrent tri-band low-noise amplifier (LNA) with a novel feedback tri-band load has been designed around 13.5/24/35 GHz. The feedback tri-band load is composed of two passive LC notch filters with feedback and provides stable and high stopband rejection especially needed in multiband components. It overcomes the dependency of stopband rejection performance on the low quality factor of integrated passive inductors. The comparative analysis and comprehensive design principles of the conventional, modified, and new feedback tri-band loads are presented. The concurrent tri-band LNA has been fabricated in a 0.18-mu m SiGe BiCMOS process and occupies an area of 1180 mu m x 500 mu m. The measured power gains are 22.4/23.7/20.2 dB at 13.5/24/35 GHz, respectively, with 36-mW power consumption from a 1.8-V supply. The tri-band LNA achieves the best noise figure (NF) of 3.4/3.2/3.7 dB and IIP3 of -13.5/-17.1/-16.1 dBm at the respective passbands. The tri-band LNA also attains less than 3.5-dB gain imbalance and 41/30-dB stopband rejection ratios in the low/high stopbands, respectively. The developed concurrent tri-band LNA achieves the lowest NF as well as the best stopband rejection ratios among the reported concurrent tri-band LNAs.