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This article presents a broadband fully integrated Doherty power amplifier (DPA) using a continuous-mode combining load. It is illustrated that the continuous-mode impedance condition in back-off and saturation for Doherty operation can be achieved with a simple impedance inverter network (IIN) that can be realized using lumped components in gallium nitride (GaN) monolithic microwave integrated circuits (MMICs). A DPA was designed and fabricated using the 250-nm GaN process to validate the proposed architecture and design methodology. The fabricated DPA chip attains around 8 W saturated power from 4.1 to 5.6 GHz. About 38.5%–46.5% drain efficiencies are achieved at 6-dB output power back-off within the entire design band. When driven by a 100-MHz OFDM signal with 6.5-dB peak-to-average power ratio (PAPR), the proposed DPA achieves better than −45-dBc adjacent channel leakage ratio (ACLR) and higher than 38% average efficiency at 4.4 and 5.2 GHz after digital predistortion. [ABSTRACT FROM AUTHOR]

In this article, a method for design automation high-efficiency power amplifiers (PAs) based on an optimization-oriented is proposed. The advantages of using particle swarm optimization to design PAs in electronic design automatic tools are analyzed, and then, simulated annealing is combined to form simulated annealing particle swarm optimization (SA-PSO). In this article, the perfectly inelastic collision used in conventional PSO is replaced by the perfectly elastic collision to improve the searching ability through reducing kinetic energy consumption. A stepped fitness function is defined to avoid the performance pit at a single-frequency point, and the concept “missing and returning” is introduced to solve the nonconvergence problem in simulation. Based on the improved SA-PSO algorithm, a broadband 10 W and a triband 6-W PA are designed. The broadband 10-W PA achieves an average drain efficiency (DE) of 62.5% and an output power of 41.2 dBm in the 0.8–3-GHz frequency band, respectively; the triband 6-W PA achieves an average of 57.4%/47.9%/47.3% DE and 37.7-/38.3-/37.4 dBm output power in 3.35–3.55-/5.75–5.95-/7.65–7.95-GHz frequency bands, respectively, while the gains of most stopbands reach less than 0 dB. With digital predistortion technology, the adjacent channel power ratio (ACPR) can reach less than −45 dBc. [ABSTRACT FROM AUTHOR]

This paper presents a modified Doherty configuration with extended bandwidth. The narrow band feature of the conventional Doherty amplifier is discussed in the view of the broadband matching. To extend the bandwidth, the post-matching architecture is employed in the proposed design. Meanwhile, broadband low-order impedance inverters are adopted to replace the quarter-wavelength transmission lines. Low-pass filter topologies are used to realize both the post matching network and the impedance inverters. A modified Doherty Power amplifier was designed and fabricated based on commercial GaN HEMT devices to validate the broadband characteristics of this configuration. The 6-dB backoff efficiencies of 47%–57% are obtained from 1.7 to 2.6 GHz (41.9% fractional bandwidth) and the measured maximum output power ranges from 44.9 to 46.3 dBm in the designed band. In particular, more than 40% efficiencies are measured at 10-dB backoff throughout the operation band. [ABSTRACT FROM PUBLISHER]

In this letter, a broadband linear and efficient power amplifier for base-stations in long-term evolution (LTE) applications is designed, fabricated, and experimentally verified, employing Cree's CGH40010F GaN HEMT. A novel method of baseband, fundamental and harmonic impedances control is used to provide high linearity and efficiency across a broad bandwidth. When producing a two-tone carrier-to-intermodulation ratio (C/I) of 30 dBc, the circuit has demonstrated a two-tone power added efficiency (PAE) between 45%–60% across the frequency range from 1.6 to 2.6 GHz while delivering 36.0–38.5 dBm average output power. For a single-carrier 20 MHz LTE signal with a peak-to-average ratio (PAR) of 6.5 dB, a measured high PAE of 40%–55% can be achieved at an average output power of 35.3–37.5 dBm with an adjacent channel leakage ratio (ACLR) of about -30 dBc from 1.6 to 2.6 GHz. [ABSTRACT FROM PUBLISHER]