Two new gallium nitride (GaN) HEMT transistors from Cree Inc. are for use in WiMAX applications covering the 4.9- to 5.8-GHz frequency band. The new CGH55015F and CGH55030F transistors, which are in sample release, are specified to operate at up to 5.8 GHz.

As business and residential customers continue to demand increased capacity and functionality for wireless networks, these transistors can enable efficient power amplifiers in small base-station formats (access points) for last mile service utilizing WiMAX-based architectures. Such outdoor units can allow Internet service providers to maximize their ROI on spectrum due to the ability to offer tiered services (enabled by improved quality of service and wider channel bandwidths) to hundreds of broadband users from a single access point.

Potential benefits offered by the new 15- and 30-watt devices include:

1. A four-fold increase in efficiency compared with similar power level GaAs MESFET devices

2. Elevated frequency operation compared with commercially available silicon LDMOS

3. Operational capability in the license-exempt 5.8-GHz ISM (industrial, scientific and medical) band as well as the 5.3- and 5.47-GHz U-NII (Unlicensed National Information Infrastructure) bands

4. Linearity of better than 2.5% EVM at average power under a WiMAX signal at 25% drain efficiency covering an instantaneous bandwidth of 5.5 to 5.8 GHz.

Both transistors are available with reference design amplifier platforms.