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30 November 2007


First semiconductor-based weather radar enters operation

Tokyo-based Toshiba Corp has delivered what it claims is the world’s first operational weather radar system that replaces electron tubes in the transmitter with a high-power semiconductor module (which uses gallium nitride power field effect transistors). The first unit has been installed at the Hydrospheric Atmospheric Research Center at Nagoya University, Japan.

The new radar is only one sixth the size of conventional equipment (with a minimum installation size of 2m x 2m) but offers comparable output power (over 200W, giving coverage of 64km), along with improved waveband efficiency and enhanced features. The Nagoya radar operates in the 9GHz frequency band (X-band).

While the new weather radar is much more compact and offers much higher performance than conventional systems, it maintains the same level of output power by adopting a combination of GaN power FETs and pulse compression technology, which strengthens peak output power. Implementation of fully digital data processing suppresses spurious levels, allowing the frequency separation required for interference suppression to be shortened to one fourth. This contributes to efficient use of crowded radio frequencies.

The new radar reinforces performance by adding innovative features such as dual polarization observation (which enhances the precision of rainfall estimation by capturing the shape and size of raindrops and cloud) and clear-air turbulence observation (which detects very low levels of signal scattering, enabling observation of air conditions including wind speed even in clear weather - a very difficult task for most weather radars).

As the new radar does not use electron tubes, which have to be periodically replaced and disposed of, it reduces environmental loads, meeting Toshiba’s goal of maximizing the eco-efficiency of its products and systems, the firm says.

Because of the limitation of bandwidth availability with increasing use of radio wave frequency resources, steady demand for solid-state radars is expected, as they can contribute to more efficient use of frequencies. Toshiba says that it will market the new high-power semiconductor-based weather radar in both 9GHz band (X-band) and 5GHz band (C-band) versions, both in Japan and overseas, including sales of individual modules that build the system.

See related items:

Toshiba presents GaN power FET with record Ku-band output power

Toshiba launches X-band GaN HEMT for radar and medical applications

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