A Generic Theory for Design of Efficient Three-Stage Doherty Power Amplifiers
| Autor: | Christian Fager, Han Zhou, Jose-Ramon Perez-Cisneros, Sara Hesami, Koen Buisman |
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| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | IEEE Transactions on Microwave Theory and Techniques. 70:1242-1253 |
| ISSN: | 1557-9670 0018-9480 |
| Popis: | An analytical load--pull-based design methodology for three-stage Doherty power amplifiers (PAs) is presented and demonstrated. A compact output combiner network, together with the input phase delays, is derived directly from transistor load--pull data and the design requirements. The technique opens up a new design space for three-stage Doherty PAs with reconfigurable high-efficiency power back-off levels. The method is designed to enable high transistor power utilization by maintaining full voltage and current swings of the main and auxiliary amplifier cells. Therefore, a wide efficiency enhancement range can be achieved also with symmetrical devices. As a proof of concept, a 2.14-GHz 30-W three-stage Doherty PA with identical gallium nitride (GaN) HEMT active devices is designed, fabricated, and characterized. The prototype PA is able to linearly reproduce 20-MHz long-term evolution signals with 8.5- and 11.5-dB peak-to-average power-ratio (PAPR), providing average efficiencies of 56.6% and 46.8% at an average output power level of 36.8 and 33.8 dBm, respectively. Moreover, an average efficiency as high as 54.5% and an average output power of 36.3 dBm have been measured at an adjacent power leakage ratio of -45.7 dBc for a 100-MHz signal with 8.5 dB of PAPR, after applying digital predistortion linearization. |
| Databáze: | OpenAIRE |
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