3.2–9.7 GHz ultra-wideband low-noise amplifier with excellent stop-band rejection

Abstract

A low-power 3.2–9.7 GHz ultra-wideband low-noise amplifier (UWB LNA) with excellent stop-band rejection by 0.18 µm CMOS technology is demonstrated. High stop-band rejection is achieved by using a passive bandpass filter (BP-filter) with three finite transmission zeros (in the input terminal), one of which (ωz1=0.9 GHz) is in the low-frequency stop-band and the other two (ωz3 and ωz5) are in the high-frequency stop-band. In addition, an active notch filter is used in the output terminal to introduce another low-frequency stop-band transmission zero (ωz2) at 2.4 GHz. The LNA consumes 4.68 mW and achieves S11 of −10 to −39.5 dB, S21 of 9.3±1.5 dB, and an average NF of 6 dB over the 3.2–9.7 GHz band. The measured stop-band rejection is better than 21.6 dB for frequencies DC–2.5 and 11.2–20 GHz.