This work presents theory, design and simulation of an improved Power Amplifier (PA) based on the Doherty topology. It is theoretically shown that, using multiple iterations of source-pull and load-pull, a better main PA is accomplished. Taking into account that working conditions of the main and peak PAs affect the overall performance, the various performance indicators should be balanced. Optimal bias voltages are determined in the proposed DPA, providing higher efficiency both at full output power and at 6 dB back-off power, thus validating practical effects of the design and demonstrating a promising prospect to be used in the future wireless transmitter applications.