X-band GaN-HEMT LNA performance versus robustness trade-off

In this paper design, fabrication and test of three X-Band robust LNA MMICs in microstrip GaN technology are presented to better understand the key aspects of performance versus robustness trade-off for said components. In particular LNAs with different number of amplification stages, input device gate peripheries and topologies have been evaluated with the objective of achieving in the 8-11 GHz frequency range a NF better than 2.5dB, associated gain of circa 20 dB and overdrive power survivability better than 38 dBm. On-wafer measurements of LNA performance and robustness have been carried out in order to evaluate the incident power failure mechanisms and to individuate the best design approach for optimum performance/robustness trade-off. With one of the three LNA designs a NF < 2dB, G ass of 20 dB and P 1dB > 15dBm has been achieved in the entire 8-11GHz bandwidth. Said MMIC can withstand a 39dBm CW input power without any observable performance degradation.