A Broadband 10–43-GHz High-Gain LNA MMIC Using Coupled-Line Feedback in 0.15-μm GaAs pHEMT Technology

In this letter, a 10–43-GHz low-noise amplifier (LNA) monolithic microwave integrated circuit (MMIC) is designed in a commercial 0.15- $\mu \text{m}$ GaAs E-mode pseudomorphic high electron mobility transistor (pHEMT) technology. In the proposed LNA circuit, a novel coupled-line (CL)-based positive feedback structure is employed with the bandpass characteristic. By carefully tuning its coupling factor and arm length, the center frequency $f_{c}$ and the intensity of the feedback can be controlled, respectively. Subsequently, targeting $f_{c}$ at the higher cutting edge of the working band leads to compensated gain roll-off and extended bandwidth. Incorporating three-stage common-source (CS) architectures, an LNA prototype is fabricated with a size of 1.05 mm2 including pads. Under 2-V voltage drain drain (VDD), good performance is obtained, including 24.6-dB peak gain with 3-dB bandwidth of 33 GHz, 2.4–3.0-dB noise figure (NF), 54.5 ± 13.8-ps group delay, and 12.3/21.5-dBm best output power at 1 dB gain compression (OP1dB)/output third order intercept point (OIP3). The total dc power is 110 mW.