A low-power 3.2∼9.7GHz ultra-wideband low noise amplifier with excellent stop-band rejection using 0.18µm 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 by using a 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 S₁₁ of -10~ -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. 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 GHz, 1.8 GHz, 2.4 GHz, 17.6 GHz, and 19.5 GHz are 53.3 dB, 26.4 dB, 26.5 dB, 60 dB, and 59.5 dB, respectively.