14.5–24.5 GHz LNA with 10.6 dB Gain Tuning Range (21.4–10.8 dB) and 2.11–3.08 dB NFavg Using Body-to-Source Floating and Mutual Coupling
摘要
We demonstrate a novel 7.7–12.5 mW, 14.5–24.5 GHz low-noise amplifier (LNA). It achieves decent 10.6 dB gain tuning range (21.4–10.8 dB) and outstanding 2.11–3.08 dB average noise figure (NFavg) due to adoption of the body-to-source floating, mutual coupling, and multiple inductive peaking techniques. The CMOS LNA constitutes a common-source (CS) input stage. It is followed by current-reused CS gain and output stages. An auxiliary inductive-peaking CS stage is included in parallel with the CS output stage for gain and linearity boosting and noise figure (NF) reduction. Body-to-source floating technique, i.e., connection of the input transistor′s body to source via a large body floating impedance RBLB, is proposed. It is used for gain boosting and NF reduction due to the better suppression of the substrate noise and leakage. Mutual coupling is used to alleviate the Cgd1 effect and reduce the transmission line loss. To achieve decent 3 dB gain bandwidth (f3dB), multiple inductive peaking is used. In the high- gain mode, the LNA consumes 12.5 mW, and achieves S21 of 20.2 ± 1.5 dB for 14.5–24.5 GHz (i.e., f3dB of 10 GHz), minimum NF of 1.5 dB at 15 GHz, NFavg of 2.11 dB for 15–24 GHz, the first figure-of-merit (FOM1) of 20.8 GHz, and the second FOM (FOM2) of 4.78 1/mm2. To the authors′ knowledge, the NFavg, FOM1, and FOM2 performance are one of the best results ever reported for K- and Ka-band LNAs. Overall, the variable-gain LNA (with f3dB of 9.3–10.6 dB) consumes 7.7–12.5 mW and achieves decent gain tuning range of 10.6 dB (21.4–10.8 dB) at 19 GHz and outstanding NFavg of 2.11–3.08 dB for 15–24 GHz. The eminent performance of the 14.5–24.5 GHz LNA indicates it is suitable for low Earth orbit satellite communications.