An equivalent digital implementation of Chireix combiners under ideal source excitation

Abstract

This paper proposes a new digital implementation of the Chireix combiner when excited with idea sources. It is shown that proper baseband phase predistorsion can be made equivalent a physical combiner with optimal impedance and prescribed stubs. This technique can be used with a new stubless combiner design or retrofitted to an existing combiner with non-zero stubs. Several theoretical and experimental validations of the proposed technique are presented showing excellent agreement between theory, simulations and measurements of the digital and physical implementation of the Chireix combiner. An application of this technique for varying MQAM modulations confirms the suitability of the proposed technique to the adaptive modulation environment and its excellent ability to allow simultaneous optimization of combining efficiency.