A LOW POWER, HIGH GAIN, LOW NOISE AMPLIFIER WITH IMPROVED NOISE FIGURE AND INPUT MATCHING FOR ULTRA WIDE BAND APPLICATIONS

10.22099/ijste.2012.1514

Abstract

Abstract– In this paper, two low noise amplifiers (LNAs), one without feedback and another one
with active shunt partial feedback, are proposed for ultra wide band (UWB) applications. Both the
proposed LNAs are designed using 90 nm CMOS technology and their performance parameters
are analyzed by using post layout simulation. The proposed LNA without feedback achieves a
power gain (S21) of 16.4 dB over the band of 3 – 10.4 GHz with NF (Noise Figure) in the range of
4.9 – 5.2 dB. This high NF has been reduced to 2.4 – 2.7 dB by employing active shunt partial
feedback. The proposed LNA with active shunt partial feedback achieves a power gain of 15 dB
over the band of 2 – 12 GHz. The input matching (S11) and output matching (S22) are less than –
10 dB while maintaining the reverse isolation (S12) is less than -60 dB for both of the proposed
circuits. Both circuits, with and without active shunt partial feedback, maintain better linearity
with in-band third order input intercept point (IIP3) of – 1 dBm and – 4.242 dBm, respectively and
consume 3.643 mW and 2.862 mW of power while operating at 1 V power supply.

Keywords