An X/Ku Dual-Band Switch-Free Reconfigurable GaAs LNA MMIC Based on Coupled Line

This article presents an X/Ku dual-band switch-free reconfigurable GaAs low-noise amplifier (LNA) realized by inter-stage and output-stage coupled lines. This article is the first switch-free reconfigurable LNA design in the coupled lines structure. After amplified by the broadband drive stage, the input signal is divided into two parallel single-band stages (consists of a high-band stage and a low-band stage) by the proposed inter-stage coupled line. Two split-band signals are combined by the proposed output-stage coupled line into the output port after amplified by the single-band stages. The proposed coupled lines are also included in LNA matching networks. Dual-band operation of the proposed reconfigurable LNA is achieved by turning off drain voltages of the unused single-band transistors. The reconfigurable LNA is designed in a 0.15-μm E-mode GaAs pHEMT process. The fabricated LNA features small-signal gains of 25-25.2/20.1-28 dB, noise figure (NF) of 1.28-1.41/1.23-1.51 dB, and output 1-dB compression point of 0.5-1.7/2.2-5 dBm over 8-10/12-20 GHz, while consuming 76/91 mA of dc current, with a size of 2.0 × 1.8 mm 2 .