Millimeter-Wave GaN HEMT for Power Amplifier Applications

Gallium nitride high electron mobility transistors (GaN HEMTs) were developed for millimeter-wave high power amplifier applications. The device with a gate length of 80 nm and an InAlN barrier layer exhibited high drain current of more than 1.2 A/mm and high breakdown voltage of 73 V. A cut-off frequency fT of 113 GHz and maximum oscillation frequency fmax of 230 GHz were achieved. The output power density reached 1 W/mm with a linear gain of 6.4 dB at load-pull measurements at 90 GHz. And we extracted equivalent circuit model parameters of the millimeter-wave InAlN/GaN HEMT and showed that the model was useful in simulating the millimeter-wave power performance. Also, we report a preliminary constant bias stress test result.