25 February 2010


Mitsubishi Electric claims first GaN HEMT amplifier exclusively for satellites

Tokyo-based Mitsubishi Electric Corp has developed four models of gallium nitride high-electron mobility transistor (GaN HEMT) for 4GHz-band satellite applications, with high output power ranging from 2W to 100W, making it the first firm to market GaN HEMTs engineered exclusively for these applications, it claims.

As more satellites are meeting the end of their operational lifespan, demand for new microwave communication satellites has been growing recently, says Mitsubishi Electric. While transmitter devices in these communication satellites have traditionally used gallium arsenide (GaAs) amplifiers, GaN HEMT amplifiers offer higher efficiency, as well as high electron velocity and high breakdown fields, helping to make transmitter devices smaller, lighter and more durable.

The range includes the non-internally-impedance-matched 4GHz MGF2633GS, which has an efficiency of 50% and output power of 33dBm (2W). In addition, the internally-impedance-matched 3.7–4.2GHz MGFC43G3742S, MGFC46G3742S and MGFC50G3742 have efficiencies of 60% and output powers of 43dBm (20W), 46dBm (40W) and 50dBm (100W), respectively (with the MGFC46G3742S and MGFC50G3742 each operating in one of the three separate bands).

In particular, to achieve 100W output with GaAs amplifiers, it is necessary to combine an additional amplifier with an output of about 25W in the final stage. The MGFC50G3742S in contrast achieves 100W with a single device while retaining the same size as 25W GaAs amplifiers and offering very high power added efficiency of 60%.

The lower-output 40W, 20W and 2W GaN HEMT amplifiers, which suit use in first- and mid-stage amplification, are smaller, lighter and consume less energy.

Designed for use in satellites (which are usually used for about 10 years), the GaN HEMTs can operate for as long as 1 million hours, given a chip temperature of 175ºC and an operation voltage of 45V, and are fit to operate in the severe conditions found in space.

Sample shipments are scheduled to begin in March.

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