This article extends the theory of Class-X power amplifiers (PAs) with maximally flat waveforms by considering an arbitrary number of harmonics in the analysis. The proposed theory shows that the maximally flat voltage and current waveforms can be established with a proper fundamental load corresponding to a set of randomly and independently distributed purely reactive harmonic load impedances. It also shows that the efficiency increases with the number of harmonics regardless of the values of the harmonics. The proposed theory of Class-X PA allows for the design of a high-efficiency PA considering the effects of high-order harmonics in the presence of significant parasitic effects. To demonstrate this ability, a 3.5-GHz Class-X PA considering the effects of nine harmonics is designed and fabricated with a packaged 10-W device. The simulated and measured results show a drain efficiency of 84% for an output power of 40.5 dBm.

中文翻译：

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具有有限次谐波的 X 类功率放大器

本文通过在分析中考虑任意数量的谐波，扩展了具有最大平坦波形的 X 类功率放大器 (PA) 的理论。所提出的理论表明，可以通过与一组随机且独立分布的纯无功谐波负载阻抗相对应的适当基波负载来建立最平坦的电压和电流波形。它还表明，无论谐波的值如何，效率都会随着谐波的数量而增加。所提出的 X 类 PA 理论允许在存在显着寄生效应的情况下考虑高次谐波的影响来设计高效 PA。为了证明这种能力，我们使用封装的 10-W 器件设计并制造了考虑九次谐波影响的 3.5-GHz X 类 PA。