A Survey on RF and Microwave Doherty Power Amplifier for Mobile Handset Applications

Abstract

This survey addresses the cutting-edge load modulation microwave and radio frequency power amplifiers for next-generation wireless communication standards. The basic operational principle of the Doherty amplifier and its defective behavior that has been originated by transistor characteristics will be presented. Moreover, advance design architectures for enhancing the Doherty power amplifier’s performance in terms of higher efficiency and wider bandwidth characteristics, as well as the compact design techniques of Doherty amplifier that meets the requirements of legacy 5G handset applications, will be discussed.

Recent Technical Developments in Energy-Efficient 5G Mobile Cells: Present and Future

“…Some of these designs operate on fixed single/multiband and radiations, as in [6][7][8][9][10], while some have the feature of reconfigurability that allows them to operate in a tuned manner in which the resonant frequencies and patterns can be shifted/reconfigured even after the designs have been made [11,12]. The other two articles present recent work on a highly efficient power amplifier which will provide hardware solutions to the growing RF front-end integration challenges with additional design requirements towards energy efficiency for Pas [13,14]. A paper presenting the recent progress of 4G/5G reconfigurable filters for multimode operation with potential energy efficiency traits, good linearity, and potentially low-cost manufacturing over a variety of substrates is also included in this issue [15].…”

Load‐modulation technique without using quarter‐wavelength transmission line

“…Equations (10) and (11) can be rewritten in terms of load impedance as illustrated in the next equations:…”

“…There are at least two power amplifiers: the main amplifier, which that is operating all the time; and the peaking amplifier(s), which are working only at a high input power level as an additional current source(s). Many papers discuss the operation of the Doherty amplifier in detail [7][8][9][10]. In a classic Doherty amplifier, there are two peak efficiency points; the first peak is mainly dependent on the efficiency of the main amplifier because the peaking amplifier is off (in an ideal case), whereas the second peak efficiency is obtained when the two amplifiers are working at their full saturated power.…”

Mutual Coupling Effect on Classical Three-way Doherty Amplifier for 5G Applications

“…The wireless mobile communications systems are utilising modulation schemes with high complexity to increase the data rate and to employ the allocated bandwidth effectively due to including additional services and features that attract the user; however, the modulated signal will have an envelope which can be measured by the peak-to-average-power ratio(PAPR) [1][2][3][4][5]. The efficiency of power amplifiers can be achieved at the saturation region.…”

“…The efficiency of power amplifiers can be achieved at the saturation region. Nevertheless, for modulated signals with high PAPR, power amplifiers should be operated at the backed-off region that is far from the most efficient point to keep the required linearity performance, however, the efficiency drops sharply [3][4][5][6][7][8][9][10][11]. The back-off efficiency of power amplifier can be improved using several techniques; among them, the Doherty technique is the easiest, where no digital signal process (DSP) nor additional complex circuity is required.…”