A 2–18-GHz Reconfigurable Low-Noise Amplifier With 2.45–3.4-dB NF in 65-nm CMOS

An ultra-wideband (UWB) reconfigurable low-noise amplifier (LNA) is proposed using 65-nm CMOS technology in this article. It consists of a two-stage amplifier with a novel reconfigurable feedback network (RCFN) used at the first stage and a reconfigurable load network (RCLN) at the drain terminals of each stage. The RCFN is employed to significantly reduce the noise figure (NF) at high frequencies and enhance the overall noise performance of the wideband LNA, while the RCLN is utilized to improve the gain and ensure a well-maintained gain flatness. Meanwhile, the current-reuse technique is also introduced to achieve power reduction. With all these techniques, a reconfigurable LNA that can have UWB coverage is readily obtained with low NF, low power consumption, and excellent gain/noise flatness. To demonstrate the proposed techniques, an LNA prototype is designed, fabricated, and measured. The measurement results show that the operating frequency of LNA can cover from 2 to 18 GHz including a low band of 2–8 GHz and a high band of 8–18 GHz, while achieving a peak gain of 16.6 dB. The gain variation over the full bandwidth is within 2.2 dB while the measured NF ranges from 2.45 to 3.4 dB. Additionally, the measured input 1 dB compression point (IP1 dB) varies from −16 to −12.1 dBm. The proposed LNA operates at a power supply of 1.5 V with a power consumption of less than 12 mW. A good agreement between simulation and measurement is obtained.