Broadband Doherty Power Amplifier via Real Frequency Technique
A comprehensive method of designing a broadband Doherty power amplifier is presented in this paper. The essential limitations of bandwidth extension of a Doherty power amplifier are discussed based on the proposed structure of the Doherty power amplifier, which also takes the output matching networks of both sub amplifiers into account. The broadband matching is realized by applying the simplified real frequency technique with the desired frequency dependent optimum impedances. GaN transistors were selected to implement the circuit structure.
IEEE Transactions on Microwave Theory and Techniques