The Design And Realization Of A Highly Linear Power Amplifier Module For A Wimax/Wibro (802.16e) Base Station

We have designed and realized a highly linear power amplifier module (PAM) for a WiMAX/WiBro base station using a simple linearization method. To improve the linearity of the PAM, we use large-signal intermodulation distortion (IMD) sweet spots, which are part of the inherent properties of power transistors. These IMD sweet spots are determined by the device technologies and the bias voltage. Our PAM consists of a drive stage and a power stage. Two amplifiers are used in the drive stage, a GaAs field effect transistor (GaAs PET) and a laterally diffused metal oxide semiconductor. The linearity of the PMA can be maximally improved by the large-signal IMD sweet spots, which are tuned by the bias voltage of the GaAs PET at the signal power input of the drive stage. Using this method, the measured adjacent channel leakage ratio and power consumption efficiency of the PAM are improved by 2.9 dBc and 5.2%, respectively. The measured error vector magnitude of the PAM is only 1.45. (C) 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1952-1955,2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25374