Expands radar observation range by 2.3 times
TOKYO – Fujitsu Limited and Fujitsu Laboratories Ltd. today announced that they have developed a crystal structure that both increases current and voltage in gallium-nitride (GaN) high electron mobility transistors (HEMT), effectively tripling the output power of transistors used for transmitters in the microwave band. GaN HEMT technology can serve as a power amplifier for equipment such as weather radar: by applying the new technology to this area, it is expected that the observation range of the radar will be expanded by 2.3 times, enabling early detection of cumulonimbus clouds that can develop into torrential rainstorms.
To expand the observation range of equipment like radar, it is essential to increase the output power of the transistors used in power amplifiers. With conventional technology, however, applying high voltage could easily damage the crystals that compose a transistor. Therefore, it was technically difficult to increase current and voltage simultaneously, which is required to realize high-output power GaN HEMTs.
Fujitsu and Fujitsu Laboratories have now developed a crystal structure that improves operating voltage by dispersing the applied voltage to the transistor, and thereby prevents crystal damage (patent pending). This technology has enabled Fujitsu to successfully achieve the world’s highest power density at 19.9 watts per millimeter of gate width for GaN HEMT employing indium-aluminum-gallium nitride (InAlGaN) barrier layer.
This research was partially supported by Innovative Science and Technology Initiative for Security, established by the Acquisition, Technology & Logistics Agency (ATLA) of the Japanese Ministry of Defense. Details of this technology were announced at the International Symposium on Growth of III-Nitrides (ISGN-7), an international conference about nitride semiconductor crystal growth, held in Warsaw, Poland, from August 5-10.
For more information, see detailed announcement.