A 2-to-18 GHz Reconfigurable LNA Using Direction Switchable Coupling Presenting 0.78-to-1.24 dB NF in 0.15-μm GaAs pHEMT

This paper presents a wideband low-noise amplifier (LNA) based on the proposed direction-switchable coupling (DSC) architecture. The design features an input stage with a drain–source coupled line (DSCL) optimized for wideband noise and matching performance, rather than high-frequency gain boosting. The reconfigurable gain stage employs a DSC network integrated with a high-band compensation amplifier and an absorptive switch to split the band into low and high frequency paths, enabling precise gain compensation without introducing significant loss or complicating the matching network. Fabricated in 0.15‑μm GaAs pHEMT technology, the prototype achieves a noise figure of 0.78-to-1.24 dB, gain flatness of 1.8 dB, and an OP1dB of 9.67-to-11.11dBm across 2-to-18 GHz bandwidth, demonstrating a competitive figure of merit compared to the state-of-the-art.