ANALYSIS AND DESIGN OF A COMPACT ULTRAWIDEBAND LNA WITH 2.3 ± 0.1 dB NF AND ±14.6 ps GROUP-DELAY-VARIATION IN 0.18-μm CMOS

A low-noise figure (NF) and high power gain (S-21) 3-10 GHz ultrawideband low-noise amplifier (UWB LNA) with excellent phase linearity using standard 0.18-mu m CMOS technology is reported. An enhanced p-match input network is used to achieve wideband input impedance matching. Both high and flat S-21 and low and flat NF frequency responses are achieved by tuning the pole frequencies and pole quality factors of the second-order gain and NF frequency responses to approximate the maximally flat condition simultaneously. The LNA consumes 18 mW, achieving S-11 better than -10 dB for frequency lower than 12.2 GHz and group-delay-variation smaller than +/- 14.6 ps for frequencies 3-10 GHz. Additionally, high and flat S-21 of 13.7 +/- 1.5 dB is achieved for frequencies 1-12.5 GHz, which means the corresponding 3-dB bandwidth is 11.5 GHz. Furthermore, the LNA achieves minimum NF of 2.2 dB at 4 GHz and NF of 2.3 +/- 0.1 dB for frequencies 3-10 GHz, one of the best NF results ever reported for a 3-10 GHz CMOS UWB LNA. The measured input third-order intermodulation point (IIP3) is -0.2 dBm at 6 GHz. The chip area is only 0.601 X 0.662 mm(2) (i.e., 0.4 mm(2)) excluding the test pads. (C) 2014 Wiley Periodicals, Inc.