14.2 W/mm internally-matched AlGaN/GaN HEMT for X-band applications

High-performance X-band AlGaN/GaN high electron mobility transistor (HEMT) has been achieved by Γ-gate process in combination with source-connected field plate. Both its Schottky breakdown voltage and pinch-off breakdown voltage are higher than 100 V. Beside, excellent superimposition of direct current (DC) I–V characteristics in different Vds sweep range indicates that our GaN HEMT device is almost current collapse free. As a result, both outstanding breakdown characteristics and reduction of current collapse effect guarantee high microwave power performances. Based upon it, we have developed an internally-matched GaN HEMT amplifier with single chip of 2.5 mm gate periphery, which exhibits power density of 14.2 W/mm with 45.5 dBm (35.5 W) output power and a power added efficiency (PAE) of 48% under Vds = 48 V pulse operating condition at 8 GHz. To the best of our knowledge, it is the highest power density at this power level.

► We optimize Γ-gate process in combination with source-connected field plate.
► High breakdown voltages and low current collapse guarantee excellent capabilities.
► Internal matching circuits adopt an L–C–L topology with good tuning flexibility.
► Our GaN HEMT amplifier exhibits highest power density of 14.2 W/mm at 8 GHz.