A low‐power 3.2–9.7 GHz ultra‐wideband low‐noise amplifier with excellent stop‐band rejection using 0.18‐μm CMOS technology

A low‐power 3.2–9.7 GHz low‐noise amplifier (LNA) with excellent stop‐band rejection by 0.18‐μm CMOS technology is demonstrated.High stop‐band rejection is achieved using a planar passive band‐pass filter with three finite transmission zeros (in the input terminal of the common‐gate LNA), one of which (ω z1 = 0.9 GHz) is in the low‐frequency stop‐band and the other two (ω z3 and ω z5 ) are in the high‐frequency stop‐band. In addition, an active notch filter is used in the output terminal of the LNA to introduce another low‐frequency stop‐band transmission zero (ω z2 ) at 2.4 GHz. The LNA consumes 4.68 mW and achieves S 11 of −10 to −39.5 dB, S 21 of 9.3 ± 1.5 dB, and an average noise figure (NF) of 6 dB over the 3.2–9.7 GHz band. Moreover, the stop‐band interferers can be effectively attenuated. The measured stop‐band rejection is better than 21.6 dB for frequencies DC ∼2.5 GHz and 11.2–20 GHz. The corresponding stop‐band rejection at 0.9, 1.8, 2.4, 17.6, and 19.5 GHz are 53.3, 26.4, 26.5, 60, and 59.5 dB, respectively. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1253–1261, 2012