On high linearity ? high efficiency RF amplifier design

We present an RF-DSP co-design of a high power radio frequency (RF) power amplifier (PA) based on LDMOS technology, addressed to WiMAX base-station applications. The design increases the overall efficiency of the PA stage by means of mixed design using simulation tools that include: two tone harmonic-balance, load and source pull and the use of a digital pre-distortion (DPD) algorithm in ADS envelope Ptolemy/Matlab co-simulation. The PA was realized with MRF6S23100HR transistors biased in Class AB, using a push-pull configuration. The baluns transformers, bias and matching networks are designed using micro-strip techniques. To fulfill the standard specifications, we show that with a basic pre-distortion scheme the whole design meets the spectral mask requirements in addition to allow a considerable increase in efficiency.