A Compact Reconfigurable Dual-Path Dual-Band LNA for 5G NR FR2 Applications

This article presents a reconfigurable dual-path dual-band low noise amplifier (LNA) for fifth generation (5G) millimeter-wave (mmW) communications. A novel band-switching input matching architecture based on the cross-connected transistors is proposed to achieve optimal dual-band input matching and $g_{m}$ -boosting. This architecture allows the dual-band input transistors to share a tri-coupled-transformer-based input matching network (MN) while maintaining independent output paths. Furthermore, an 8-shaped transformer-based decoupling interstage MN provides optimal interstage impedance matching in the low-band and high-band modes while sharing the same footprints with negligible performance degradation. In addition, to suppress interference from image bands, a notch filter based on negative resistance is integrated into the output MN. A prototype of the proposed LNA was fabricated in TSMC 65-nm bulk CMOS process with a compact core size of 0.132 mm². The measurement results show that the proposed LNA covers the n257 and n260 bands, achieving a peak gain of 17.8/17.9 dB at 28/37.1 GHz and image rejection (IR) of 37.4/25.9 dBc at 38.2/28.5 GHz, respectively. The measured noise figure (NF) reaches minimum values of 3.23/3.63 dB at 28/37.8 GHz. Moreover, the power consumptions of the two modes are 19.9 and 21.2 mW, respectively, from a 1.0-V supply voltage.