In this letter, a distributed element‐based load network is proposed for designing a high‐efficiency dual‐band (DB) 5‐W Class‐E power amplifier (PA), at two widely spaced frequencies of 2.4 and 5.8 GHz. This network consists of two different stages. The first stage deploys a flexible network configuration with crossed transmission lines (TLINs) to provide concurrent DB fundamental matching in a closed‐form derivation, which transforms the standard resistance of 50 Ω directly to the optimal complex impedances. By tolerating the combination of the up‐side and down‐side TLINs, the size of the overall circuit as well as the implementation complexity are reduced. The second stage uses a DB TLIN‐based resonator preceded by a series 50 Ω stub to control the harmonic impedances without altering the fundamental impedances, ensuring high efficiency at the fundamental frequencies. The measured prototype shows highest power added efficiency (PAE) of around 62.9% and 61.7% with output power of about 39 and 35 dBm at 2.45 and 5.76 GHz, respectively.

中文翻译：

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适用于5W 2.4 / 5.8 GHz并发双频E类功率放大器的高效设计

在这封信中，提出了一种基于分布式元素的负载网络，用于设计两个宽间隔的2.4 GHz和5.8 GHz频率的高效双频（DB）5 W E类功率放大器（PA）。该网络包括两个不同的阶段。第一阶段采用交叉传输线（TLIN）部署灵活的网络配置，以闭合形式导出并发DB基本匹配，将50Ω的标准电阻直接转换为最佳复数阻抗。通过容忍上侧和下侧TLIN的组合，可以减小整个电路的尺寸以及实现的复杂性。第二阶段使用基于DB TLIN的谐振器，其前接一个串联的50Ω短截线，以控制谐波阻抗，而无需改变基波阻抗，确保基频上的高效率。测得的原型显示出最高的功率附加效率（PAE）约为62.9％和61.7％，在2.45 GHz和5.76 GHz时的输出功率分别约为39 dBm和35 dBm。