This letter presents the design strategy for an ultrawideband, high-efficiency hybrid power amplifier based on a commercial GaN-HEMT. The measurement results demonstrate a state-of-the-art fractional bandwidth of 145.5%, with saturated output power higher than 10 W from 0.6 to 3.8 GHz and power added efficiency exceeding 46% in the whole band, thus covering most of the mobile frequencies and making this device suitable for small-base station applications. The simple design approach exploits a N-section transformer, and allows for a priori estimation of the bandwidth: in the proposed case, a good agreement between estimated and measured bandwidth is obtained.

This paper presents a simple method to design wideband Doherty power amplifiers (DPAs) based on the synthesis of a combiner network which can mimic the response of an ideal compensation of the device reactive output equivalent network and exploit the maximum power capabilities of the device. Using the Wolfspeed’s CGH40006 and CG2H40025 GaN HEMT devices, two DPAs were designed and simulated to demonstrate the effectiveness of the proposed approach. In both cases, a 1.4 GHz bandwidth was obtained together with an efficiency higher than 44 and 49% at 6 dB OBO. The saturated output power was higher than 41.2 and 47 dBm over the band, for the DPAs using the CGH40006 and CG2H40025 devices, respectively.

This paper presents a strategy to design ultrawideband power amplifiers with a fractional bandwidth of approximately 200%. It exploits a simple output matching network, which consists of a series transmission lines together with a shunt stub, to compensate the output parasitic network of the device. Following this, a multisection transformer is implemented to obtain the optimal load at the intrinsic drain plane. As design examples, several output matching networks were designed for two different size GaN HEMT devices. One of these examples was implemented and characterized, and a drain efficiency from 52% to 70% and an output power between 40 dBm and 42.5 dBm were obtained, over 67% of the 5G sub-6-GHz band (i.e., 0.1 to 4 GHz). The aforementioned results, to the best of the authors’ knowledge, represent the state of the art in broadband power amplifiers.

Resumen:Este artículo presenta el concepto general del amplificador de potencia Doherty, resaltando su superioridad, en términos de eficiencia promedio, con respecto a amplificadores de una etapa. Además, se presenta la posibilidad de incluir etapas de pre-amplificación en las ramas del amplificador Doherty, con el objetivo de incrementar su ganancia Abstract:This paper shows the general concept of the Doherty power amplifier, highlighting its superiority, in terms of average efficiency, regarding to single-stage power amplifiers. Furthermore, the posibility of including preamplification stages, in both branches of the Doherty power amplifier is presented, with the goal of increasing its gain.Palabras clave: Amplificador de potencia, Doherty, comunicaciones inalámbricas, alta ganancia, eficiencia.