GaN HEMT Based MMIC High Gain Low-Noise Amplifiers for S-Band Applications

In this paper design, fabrication and measurement of three Gallium Nitride, GaN, High Electron Mobility Transistor, HEMT, based Monolithic Microwave Integrated Circuit, MMIC, Low-Noise Amplifiers, LNAs, are presented. Inductive Source Feedback, ISF, topology is used to obtain both better input return loss and noise figure, NF. All three designs achieve higher than 21 dB gain, better than 10 dB input return loss and their NF values are 1.7 dB, 1.3 dB and 0.9 dB in S-band. LNA-1 is 3 ⨯ 5 mm and LNA-2 is 2 ⨯ 3.5 mm, with a % 46 size reduction upon the first version. High resistive gate biasing is utilized in LNA-3 to increase input power handling. Due to the lack of precise control over SiN layer thickness in process in GaN technology, this fabrication step is subject to variations which affects capacitor values. LNA-2 and LNA-3 designs' matching circuitries and overall characteristics are not influenced too much by a change of capacitor values. Targeted bandwidth is 2.7-3.5 GHz, achieved frequency range is 1.5 GHz (from 2.5 GHz to 4 GHz). The three LNA designs have 28.1 dBm, 33.4 dBm, and 35.8 dBm output third-order intercept point, OIP3; and output powers at 1-dB compression points, P1dB, are 18.2 dBm, 23.3 dBm and 25.9 dBm respectively. For all three LNA designs, group delay, τ$g$, is less than 0.3 nanoseconds.