GaN brings weather radar into digital age
The world s first weather radar that uses a high-power semiconductor module, based on GaN, has been installed at Japan's Nagoya University.
Toshiba Corporation says that its GaN field effect transistors (FETs) allow it to manufacture systems without the electron tubes that have previously been used in weather radar transmitter modules.
The initial 9 GHz radar has been made for Nagoya s Hydrospheric Atmospheric Research Center using Toshiba's existing X-band GaN FET technology, and came into operation on November 28.
The conglomerate will produce further individual X-band GaN radars to order and will also use its C-band FETs to make radars that operate in the 5 GHz range.
A Toshiba spokesperson said that the development of semiconductor weather radar was made possible by its GaN products, because they offer twice the power output over similar sized silicon devices.
At 2m by 2m, the new radar system is only one-sixth of the size of electron-tube radars currently in use, and matches the incumbent technology for price. By propagating a signal with a 200 W transmit power, the radar can scan a range of 64 km.
The FETs are more reliable than electron tubes, which often need replacing during the lifetime of a system, and therefore the running costs of the semiconductor radar should be much lower.
By moving to GaN transistors, weather radar will also be able to make a more efficient use of the radio spectrum, by narrowing the frequency range scanned.
According to Toshiba the switch to solid-state will also improve radar performance: “The new radar also enhances the precision of rainfall estimation by capturing the shape and size of raindrops and clouds,” the company explained.
“[It] detects air conditions including wind speed even in very clear weather "“ a very difficult task for most weather radars.”
