46‐W high efficiency unbalanced doherty power amplifier in extended output power back‐off

Abstract

A 46‐W unbalanced Doherty amplifier is proposed to obtain high efficiency at the output power back‐off beyond 6 dB using the same type of transistors in both the main and the peaking amplifier.An added power efficiency of 38% and an adjacent channel power ratio of −35.6 dBc were measured for a CDMA2000 1FA signal. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1612–1614, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26865

High Efficiency Two‐Stage Unbalanced Doherty Power Amplifier for Lte Applications

“…Figure shows simulated efficiency and intermodulation distortion (IMD) results of the conventional UDPA and proposed two‐stage UDPA for the two‐tone signal with a 10 MHz bandwidth. The simulation results of the proposed UDPA with embedded drivers show complete compensation of the maximum output power reduction of the conventional UDPA.…”

“…A two‐stage UDPA has a structure in which the drive amplifiers are directly connected to the final power amplifier. The theoretical explanation and the operational principles of the UDPA are described in . Figure is a simplified diagram of a two‐stage UDPA.…”

“…The high efficiency power amplifier using the Doherty technique has been successfully applied to repeaters and base stations in wireless communication applications. Various Doherty structures were proposed and demonstrated, such as symmetric, asymmetric, N‐way, and unbalanced Doherty amplifiers . To improve the linearity of the Doherty amplifiers using a high peak to average ratio (PAR), the output power back‐off (OPBO) should be extended beyond 6 dB.…”

“…To improve the linearity of the Doherty amplifiers using a high peak to average ratio (PAR), the output power back‐off (OPBO) should be extended beyond 6 dB. The unbalanced Doherty power amplifier (UDPA) is attractive for efficiency enhancement at the OPBO beyond 6 dB . Even though the unbalanced amplifier uses the same type of transistors in both the main and the peaking amplifier, the OPBO can be extended beyond 6 dB through the λ /4 transformer impedance replacing at the main amplifier output.…”

Design of an S-Band Two-Way Inverted Asymmetrical Doherty Power Amplifier for Long Term Evolution Applications

“…Since the conventional two-way symmetrical Doherty PA exhibits the peak efficiency at a 6 dB back-off power in theory [6], it is not a good choice for transmitting high PAR signals Various new technologies such as two-way asymmetrical Doherty structure, N -way Doherty structure have been researched [7][8][9]. However, the N -way Doherty PAs result in an increase in PCB layout area and the complexity of circuit design.…”