A 5.8-GHz LNA with image rejection and gain control based on 0.18-μm CMOS

This paper presents a low‐noise amplifier (LNA) design which includes image rejection and gain control. The proposed LNA adopts a cascode topology with a notch filter combined with a gain control function. The performance of the proposed LNA is compared with conventional cascode topology and improvements in noise figure and image rejection by 0.3 and 11.5 dB, respectively, are confirmed. The proposed 5.8‐GHz LNA is implemented using 0.18‐μm CMOS technology. Measured high‐gain mode performances show noise figure (NF) = 1.4 dB, gain = 16.5 dB, and input‐P1dB = −8 dBm; with low‐gain mode, the gain reduces to 5.5 dB while the linearity improves to input‐P1dB = 10 dBm. The LNA dissipates 4 mA from a 1.8 V supply. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 477–480, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11094