A 2 GHz, 85W Uneven GaN Doherty power amplifier

Modern wireless communication standards, e.g. UMTS, are making use of modulation schemes, resulting in signals with high levels of peak-to-average power ratio (PAR). For example, the W-CDMA signal used in UMTS-standard has typical PAR levels above 6 dB. Conventional single-ended power amplifiers will result in low levels of average efficiency, if they were implemented in the transmitters of such communication systems. Furthermore, power control in cellular communication networks is a crucial requirement, in both, base station and handset transmitters, to reduce the operating cost on the base station side, and to minimize the adjacent-channel interference. It is though apparent, that power amplifiers in modern wireless communication networks, should operate over a wide output back off region, with high levels of efficiency, maintained over the power operating range. The Doherty power amplifier technique is a competitive solution for efficiency enhancement, which has been recently widely investigated, due to its relatively simple circuitry and ease of implementation.