Common-Gate LNA MMIC With Switching Feature Using GaN-HEMT for 5G RF Front-End

This letter presents a novel three-stage gallium nitride (GaN)-HEMT low-noise amplifier (LNA) with an integrated switch. It is intended to replace the combination of the antenna switch and the LNA, which is common in GaN monolithic microwave integrated circuit (MMIC) transceiver realizations. The LNA employs at the input two common-gate (CG) stages that can be switched from low-noise amplification to high-isolation mode. In the low-noise amplification receiver (RX) mode, the LNA performs as a standard amplifier with a gain of 25.5 dB and a low-noise figure of 2.1 dB at 5 GHz. When switched into the OFF state, i.e., transmission mode, it provides an isolation of around 50 dB at 5 GHz, which is verified up to an input power of 30 dBm. The proposed integrated concept allows to omit the antenna switch, which enables a very compact and low-loss transceiver implementation.