High Gain, High Efficiency 12V pHEMT Power Transistors for WiMAX Applications

The combination of Freescale´s production pHEMT process with a self-aligned field plate, creates a device technology that delivers high gain and efficiency while meeting WiMAX linearity requirements. Compared to the standard production process, field plate devices show gain improvement of about 3 dB while other important device parameters such as power density, linearity, and efficiency are maintained. To demonstrate the improved performance of the field plate technology, three devices with total gate width of 7.2 mm, 14.4 mm, and 25.2 mm were designed and evaluated using a 64 QAM OFDM signal at 3.55 GHz. The devices delivered power of 28.5 dBm, 31.2 dBm, and 33 dBm, respectively, while meeting an EVM linearity requirement of 3%.