Design and implementation of A 1.9–22.5 GHz CMOS wideband LNA with dual‐RLC‐branch wideband input and output matching networks

Abstract

ABSTRACTA 1.9–22.5 GHz wideband low‐noise amplifier (LNA) based on the current‐reused cascade configuration in 90 nm CMOS is reported. The wideband input‐impedance matching was achieved by taking advantage of the resistive shunt‐shunt feedback in conjunction with a parallel LC load to make the input network equivalent to two parallel resistor‐inductor‐capacitor (RLC) branches, that is, a second‐order wideband band‐pass filter (BPF). The wideband output‐impedance matching was also achieved by making the output network equivalent to a second‐order wideband BPF. Theoretical analysis shows that both the frequency response of input matching and noise figure (NF) can be described by second‐order functions with quality factors as parameters. The LNA (LNA‐1) dissipates 9.96 mW and achieves low and flat NF of 3.24 ± 0.5 dB and high and flat S21 of 12.02 ± 1.5 dB for frequencies 1.9–22.5 GHz. The corresponding figure of merit (FOM) is 7.44 GHz/mW, one of the highest FOMs ever reported for a wideband LNA with bandwidth around 20 GHz. To study the effect of self‐forward body bias (SFBB) on LNA‐1, an LNA‐2 consisting of LNA‐1 and SFBB is implemented for comparison. The results show LNA‐2 consumes less power at the expense of a worse NF due to the body noise. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:677–684, 2014