A 7.2-27.3 GHz CMOS LNA With 3.51 ±0.21 dB Noise Figure Using Multistage Noise Matching Technique

A wideband low-noise amplifier (LNA) with low and flat noise figure (NF) is presented in this article. For conventional wideband noise matching, the noise performance in the high-frequency region of the entire wideband is usually deteriorated due to the frequency-dependent nature of the minimum noise figure (NF min ) for a MOSFET. To address this issue, a novel wideband noise matching approach aiming at noise matching in high band is proposed. This approach can reduce the NF in high band at the cost of a slight NF increase in low band, eventually achieving a low and flat NF and thus a better overall noise performance for a wideband LNA. In addition, the multistage noise matching technique is employed at high frequencies to further reduce the NF caused by the second amplification stage. To validate the proposed techniques, a two-stage LNA prototype was designed and fabricated using a 65 nm CMOS process. The experimental results indicate a peak gain of 16.6 dB with a −3 dB bandwidth (BW) from 7.2 to 27.3 GHz (a fractional BW of 116%). Within the entire band of interest, the simulated NF is low and almost constant (3.3-3.4 dB), while the measured NF falls within the range of 3.30-3.72 dB. Considering the uncertainty of NF measurement, a 0.21 dB NF flatness is one of the best results among the reported millimeter-wave wideband LNAs. The measured third-order input intercept point (IIP3) is −6 dBm at 20 GHz, while the power consumption is 13.2 mW. In addition, only two passive transformers are used in this design, leading to a compact chip core area (0.14 mm 2 ).