Utilizing five-port down-converter in adaptive linearization of base station envelope tracking power amplifiers

A high linear, high efficient base station power amplifier is presented. For increasing average efficiency in the highly modulated signal amplification, an envelope tracking technique is employed. Linearization is done using an adaptive digital pre-distortion (DPD). A passive five-port fabric is used in the feedback path instead of conventional demodulators which reduces size, power consumption and cost. By using such adaptive DPD in the envelope tracking power amplifier (ET-PA), the simulated average efficiency on an LDMOSFET for a WCDMA signal is obtained more than 70% over 20 dBm input power and ACLR is improved about 15 dB at 5 MHz offset.