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