An InGaP‐GaAs HBT low‐noise amplifier for 2.4/5.2/5.7‐GHz WLAN applications

A 2.4/5.2/5.7‐GHz triple‐band low‐noise amplifier (LNA) achieved by switching between different base bias currents ( I B ) using InGaP‐GaAs HBT technology is reported for the first time. Transducer gains ( S 21 ) of 14.6 and 11/9.5 dB, input return losses ( S 11 ) of −18.7 and −21.0/−11.5 dB, output return losses ( S 22 ) of −20 and −22.7/−24.9 dB, reverse isolation ( S 12 ) of −50.5 and −44.4/−44.4 dB, and noise figures of 3.35 and 2.54/2.71 dB were achieved at 2.4 and 5.2/5.7 GHz, respectively. The input 1‐dB compression point (P 1dB ) and input 3 rd ‐order intercept point (IIP3) of −8.5 and −1 dBm, respectively, were also achieved at 5.2 GHz. The power consumptions are only 7.6 and 3.6 mW for the 2.4‐ and 5.2/5.7‐GHz bands, respectively. The LNA only occupies an area of 300 × 500 μm, excluding the test pads because only one inductor is used. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 539–542, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20528