Low-noise and high-linearity LNA based on InGaP/GaAs HBT for 5.3-GHz WLAN

This paper presents a low-noise and high-linearity LNA based on InGaP/GaAs HBT for 5.3-GHz WLAN. Previous LNAs based on FET series (such as HEMTs) show excellent noise characteristics, but poor linearity. The InGaP/GaAs HBT LNA shows excellent linearity and noise characteristics because of its high base-doping concentration. The proposed LNA is fully integrated in a single chip of area 0.9 × 0.9 mm2 with high-Q spiral inductors and MIM capacitors, and is biased at the current point for optimum noise figure and gain characteristics; furthermore, excellent linearity is achieved. The measured result of the proposed LNA shows 13-dB gain, 2.1-dB noise figure, and excellent linearity with IIP3 of 5.5 dBm. The figure of merit (FOM), defined as a function of the linearity and noise figure, is 20.1 dB, which is the best result among previous LNAs. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 550–553, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21047