Keiichi Matsushita

An X-band 250W solid-state power amplifier using GaN power HEMTs

More than 250 W of peak output power (pulse width 64 mus, duty cycle 7%) is achieved with newly developed X-band solid-state power amplifier. The final stage of the SSPA consists of four 80 W class GaN power HEMTs and a low loss 4-way combiner. Compared with the conventional klystron tubes, our newly developed SSPAs are smaller, more reliable and require less amounts of occupied frequency bandwidth.

X-band AlGaN/GaN HEMT with over 80W Output Power

AlGaN/GaN high electron mobility transistors (HEMTs) were developed for X-band applications. The operating voltage and temperature dependence of output power characteristics in CW operating conditions were investigated. The developed AlGaN/GaN HEMT with combined two dies of 11.52 mm gate periphery exhibits output power of over 81.3W with a power added efficiency (PAE) of 34% under VDS=30V, CW operating condition at 9.5GHz, and a gain compression level of 3dB

Ku-band AlGaN/GaN-HEMT with over 30% of PAE

AlGaN/GaN High Electron Mobility Transistors (HEMTs) were improved for X-band and Ku-band applications. The power added efficiency (PAE) was achieved over 40% for X-band and over 30% for Ku-band. The developed devices combined two AlGaN/GaN HEMTs of 12 mm gate periphery and exhibited the output power of over 50W. An AlGaN/GaN HEMT with four dies of 12 mm gate periphery was developed and exhibited the output power of over 120W.

Ku-band AlGaN/GaN HEMT with over 30W

AlGaN/GaN high electron mobility transistors (HEMTs) were developed for Ku-band applications. The operating voltage characteristics in CW operating conditions were investigated. The developed AlGaN/GaN HEMT with combined two dies of 12 mm gate periphery exhibits output power of over 30 W with a power added efficiency (PAE) of 12% under VDS = 30 V, CW operating condition at 14.25 GHz, and a gain compression level of 3 dB.

Developing GaN HEMTs for Ka-Band with 20W

AlGaN/GaN High Electron Mobility Transistors(HEMTs) were developed for Ka-band. The developed device showed 138 GHz of fmax, which depended on the thickness of the AlGaN barrier layer and the gate length. It had a 6.4 mm gate periphery on a metal carrier plate. The output power achieved 20 W with impedance matching circuits.

Numerical Device Model for Reliable AlGaN/GaN HEMT Structure Design Based on Shear Stress

A numerical device model is proposed for the design of reliable AlGaN/GaN HEMT structures. In the model, shear stress due to the inverse piezoelectric effect is used to predict high-temperature DC stress test results. The calculated shear stress is compared with test results for various AlGaN/GaN HEMT structures. The comparison shows that structures passing the test have shear stress lower than 0.19 GPa under the test conditions. An AlGaN/GaN HEMT structure for the Ka band was designed so that stress would be lower than this value. The designed structure was fabricated and passed the test. These results indicate that the model can be used to design reliable AlGaN/GaN HEMT structures.

Developing GaN HEMTs for high efficiency

An efficiency of AlGaN/GaN High Electron Mobility Transistors(HEMTs) were improved for Ku band. The AlGaN/GaN HEMTs were developed with an achievable fmax of 138GHz, which depended on the thickness of the AlGaN barrier layer and the gate length. A 6.4mm gate periphery device was thereafter designed with matching circuits on an alumina substrate on a metal carrier plate. The output power achieved 20 W at 26GHz.