High-power and high-efficiency GaN HEMT amplifiers

We report a current status of high-power GaN HEMTs for high-power and high-efficiency amplifiers with higher efficiency by 5% especially at a backed-off region than the conventional GaN HEMTs. First, we introduce our specific device structure GaN HEMT with dispersion-free I-V characteristics, low Idsq-drift and high reliability. Record average drain efficiency of over 50% and linear gain of 17.2 dB were obtained at an output power of 45 dBm and 2.5 GHz. Next, we discuss their reliability with high-temperature life tests resulting in their estimated life of over 1 x 10⁶ hours at Tj of 200 °C. Finally, we describe the next generation GaN HEMTs for millimeter-wave applications.