Wideband, Robust Low Noise Amplifier

Abstract

Low noise amplifiers are important parts of receiver units in radio systems that enables communication between military vehicles. The use of such an amplifier in military and maritime equipment poses challenges to the robustness of the amplifier. This report deals with the design and simulations of a low noise amplifier using the robust GaN MMIC GH25-10 process from Wolfspeed. It is specified that such an amplifier should deliver more than 13dB gain and have less than 2dB in noise figure for a 1.3 - 5.8GHz frequency band. Simulations of the amplifier in Keysight s Advanced Design System shows a maximum gain of 33.8dB at 1.3GHz while a minimum of 13.9dB is located at 5.8GHz. The noise figure demonstrates to be 1.68dB at most for 5.8GHz with a minimum of 1.08dB at 1.8GHz. The designed amplifier is also found to be unconditional stable from simulations. Intermodulation distortion is simulated in a two-tone test marking the linearity of the amplifier, while the output power is simulated in a single-tone test. To give an idea of robustness, there have been done simulations that shows at which input powers the amplifier reaches maximum ratings of the gate current, gate-source voltage and drain-source voltage. Junction temperature is simulated for different input powers with an ambient temperature of 85◦C for both transistors to further prove the robustness. Finally, the work has resulted in a layout that has been tested through an electromagnetic simulation. The results of this last simulation matches the previously simulated values for noise figure, gain and stability.