Accurate Offset Line Design of Doherty Amplifier With Compensation of Peaking Amplifier Phase Variation

High Efficiency Power Amplifiers for Modern Mobile Communications: The Load-Modulation Approach

“…In [53,55], it is demonstrated how the insertion of two transmission lines, with characteristic impedance equal to the load impedance at saturation and of proper length, placed at the output of both the Main and Auxiliary devices, can improve load modulation, and thus both linearity and efficiency. In particular, the offset line at the output of the Auxiliary amplifier forces the necessary almost-ideal open-circuit condition at low power levels, while the one at the output of the Main stage keeps under control the load matching within the whole Doherty region, thus maximizing the power efficiency.…”

“…For example, in [55], two additional offset lines are adopted to enhance back-off efficiency, while in [64], it is shown that a properly designed offset line added at the Auxiliary input can improve linearity of the DPA. In [65], it is demonstrated that the use of an extended-resonance input power divider yields an adaptive input-dependent power division between the Main and Auxiliary stages, compensating the phase misalignment and thus enhancing both linearity and efficiency.…”

“…In [55,91], it is shown how to enhance back-off efficiency through adaptive power distribution and phase alignment algorithms, ensuring minimized wasted power when the Auxiliary device is off, as well as phase-aligned output currents during load modulation. In [92], the HEPR is improved by dynamically adjusting the amplitude and phase of the input signal of the two amplifiers, and three-input versions also exist [93] for further HEPR enhancement.…”

High efficiency Doherty power amplifier based on asymmetrical matching network

“…The requirement for increasing the amount of transmitted data within a limited bandwidth using wireless communication systems is growing rapidly and is expected to continue, especially with the developments of the LTE-Advanced system, where the user is being attracted by the video streaming and multimedia data in addition to the internet of things (IoT) technology revolution [1]- [3]. Hence, the fifthgeneration (5G) wireless communication will include several technologies that can help to achieve the promised goals of the 5G.…”

“…In addition, it is also a component which consumes a lot of the energy [2]. PA with high efficiency is always an important research topic; because a low efficiency PA consumes a lot of power, requiring a large heat sink and increasing system operation cost [3]. Modulated signals with high PAPR require PAs to be operated at back-off (BO) power levels from its saturation point (i.e.…”