Concurrent dual-band balanced low-noise amplifier with optimized matching network for high-stability wireless and radar applications

Abstract We present a concurrent dual-band balanced low-noise amplifier (LNA) operating at 2.4 GHz and 5.2 GHz, designed using a GaAs HJFET for high sensitivity and stability. The proposed architecture combines a dual-band impedance transformer with compact dual-band branch-line couplers at both input and output, forming a balanced configuration that enhances impedance matching, linearity, and port isolation. Co-simulations performed in ADS and HFSS show gains of 15.3 dB and 15.9 dB and ultra-low noise figures of 0.7 dB and 0.9 dB at the two center frequencies. The input and output return losses are below −15 dB, ensuring excellent impedance matching and system stability. To support practical feasibility, the dual-band coupler and a single-ended amplifier branch were fabricated and experimentally characterized, demonstrating strong agreement with simulation. These results confirm the viability of the design and its suitability for advanced wireless and radar front-end applications requiring robust dual-band performance.