A 28V 250W GaAs power FET with high gain of 15.5 dB for W-CDMA base stations

We, for the first time, have developed a high power 250W push-pull GaAs power FET operated at 28V drain bias voltage. This FET consists of four FET chips newly developed for 28V drain bias operation and single stage internal network for both input and output matching circuits. A saturated power of 54 dBm (250W) and an associated gain of 15.5 dB were achieved with this device in the 2.1GHz band with a two carrier W-CDMA signal applied and a supply voltage of 28V. This high power gain is the highest among the FET's with an output power of exceeding 200W ever reported. A third order intermodulation distortion (IM3) obtained at an averaged output power of 46 dBm (40W) was as small as -33dBc, providing a drain efficiency of 25%. Furthermore, we demonstrated that this device can be operated at 32V drain bias voltage, which exhibits the lower IM3(-38dBc).