BUTLER DOHERTY POWER AMPLIFIER

摘要

A Butler Doherty power amplifier suitable for wireless communications systems comprising of a Butler matrix network and a Doherty power amplifying stage, is disclosed. The Butler matrix network which consists of an input processing stage comprising a first hybrid or coupler, a first phase difference setting stage, a second hybrid or coupler, and a second phase difference setting stage, a plurality of power amplifier driver stages, a third hybrid or coupler and a plurality of phase setting stages is capable of accepting an RF input signal, maintaining equal power sharing in a plurality of power amplifier driver stages and supplying the Doherty power amplifying stage with independently controlled drive signals. The Doherty power amplifying stage which consists of a carrier power amplifier with an associated matching network, a peaking power amplifier with an associated matching network, a plurality of phase setting stages and Doherty combining network, is capable of accepting drive signals from the Butler splitting stage, amplifying these signals with high efficiency under Doherty operation and providing the resultant signal to an output load. The Butler matrix network facilitates the optimal distribution of power to the constituent stages of the Doherty amplifier such that optimum linearity and efficiency is maintained for high peak to average ratio RF signals.