Acimovic, Igor2013-08-192018-02-1020132013-08-19http://hdl.handle.net/10393/24406http://dx.doi.org/10.20381/ruor-1503In this thesis we introduce a two-way Doherty amplifier architecture with multiple feedbacks for digital predistortion based on impedance-inverting directional coupler (transcoupler). The tunable two-way Doherty amplifier with a tuned circulator-based impedance inverter is presented. Compact N-way Doherty architectures that subsume impedance inverter and offset line functionality into output matching networks are derived. Comprehensive N-way Doherty amplifier design and analysis techniques based on load-pull characterization of active devices and impedance modulation effects are developed. These techniques were then applied to the design of a two-way Doherty amplifier and a three-way Doherty amplifier which were manufactured and their performance measured and compared to the amplifier performance specifications and simulated results.enPower amplifier (PA)Doherty amplifierload-pull measurementefficiency enhancementpeak-to-averageimpedance matchinglinearityimpedance modulationThesis