Modified Doherty combiner with adjustable phase deviation

In this paper, we propose a newly enhanced Doherty combiner by adding a 180° transmission line to the stage of the peaking amplifier of a typical Doherty combiner such that the designer can easily construct a combiner having a phase deviation to be turned on within the intended bandwidth. Given such characteristics, the proposed structure provides wider phase bandwidth and better performance with respect to power combining rate than the conventional structure does. We introduce formulas for the design variables of the added transmission line and also demonstrate its validity through circuit design and experiment.