CGH55015F and CGH55030F GaN HEMTPresented as the first such devices of their type, the 15- and 30-W CGH55015F and CGH55030F gallium nitride (GaN) HEMT transistors from Cree are intended for use in WiMAX applications covering the 4.9 to 5.8 GHz frequency band. Providing a four-fold increase in efficiency compared with similar GaAs MESFET devices, the transistors also have a linearity of better than 2.5% EVM at average power under a WiMAX signal at 25% drain.