Symmetrical Doherty Power Amplifier With Extended Efficiency Range

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

“…The main drawbacks of this solution are device under-utilization and increased bias circuit complexity. In [48] and [49], instead, a wide HEPR for a symmetric DPA is achieved by modifying the output power combiner, thus ensuring a high power utilization for both transistors, while in [50], electronically-tunable devices are adopted to dynamically adjust circuit parameters as a function of the average input power level, maintaining high efficiency even in deep OBO conditions. A novel technique for enhancing the HEPR of traditional symmetrical DPAs, based on adopting an output impedance for the Auxiliary stage different from an open circuit and changing the phase delay of the IIN, has been recently proposed in [51].…”

“…More recently, the co-design technique has been further enhanced by adopting a black-box approach for the entire output combiner, thus eliminating the limitation imposed by the presence of the quarter wavelength impedance inverting network. In this way, the phase difference between the two branches becomes an additional degree of freedom and can be optimized in order to achieve better efficiency and linearity, as in [60], to enhance HEPR as in [48], or to improve the bandwidth as described in [61], where the analytical analysis of this novel approach is introduced, presenting a technique for wide-band power combiners' design that can be applied both to Doherty and to Chireix PAs (Section 4).…”

A harmonic controlled symmetric Doherty power amplifier with extended back-off power range

“…To amplify these signals efficiently, the power amplifiers (PAs) require efficiency enhancement at back-off powers [1]. Thus, the Doherty power amplifier (DPA) has been extensively used due to its simple implementation and significant efficiency enhancement [2,3,4,5,6,7,8,9]. To further improve the efficiency, the harmonic controlled DPAs based on class-F and class-J modes have been presented [10,11].…”

“…Hence, it is desirable to design harmonic controlled DPAs with extended back-off power range. In [5], a symmetric DPA has been established as a generalized circuit block, and extended efficiency range was achieved by maintaining the full voltage and current swings of the transistors. However, it only focused on fundamental impedance matching and the realization of the output matching network (OMN) is straightforward using Πor T-networks, which can hardly meet the design requirements of the harmonic controlled DPA.…”

A Doherty Power Amplifier with Large Back‐Off Power Range Using Integrated Enhancing Reactance

“…These two kinds of DPAs utilize excessive modulation current of the peaking amplifier to achieve enlarged load span of the carrier amplifier for extended BOP range, leading to tradeoffs between design complexity, cost, and power utilization factor. To overcome the disadvantages of the aforementioned DPAs, modified symmetric DPAs have been proposed recently to attain larger than 6 dB high-efficiency range, which employ complex combining load technique [17] or maintain full voltage and current swings of both carrier and peaking amplifiers [18]. However, these approaches might suffer from complicated design methodology.…”