This article presents a very compact highly efficient solid-state power amplifier (SSPA) module at kilowatt level in a push–pull architecture. This SSPA is intended to be used as a modular RF source for a 20 kW cyclotron that operates in the low VHF band for radioisotopes production. For a compact design, a lumped $LC$ balun is adopted instead of a traditional ferrite transformer for the 180° phase shift requirement of the push–pull architecture. Lumped harmonic traps are employed as harmonic tuning to achieve higher efficiency. This implementation enables an ultracompact design realized on a 90 mm $\times \,\, 70$ mm circuit board. Improved efficiency at reduced output power is achieved through a static supply voltage variation, which gives more than 90% efficiency over a 5 dB output power range. This approach enables considerable energy saving when applied to the whole cyclotron system. The achieved results show that the proposed SSPA with drain supply modulation is a very promising architecture for very high-power RF sources in cyclotrons for radioisotope production.

中文翻译：

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用于放射性同位素生产回旋加速器的紧凑型高效千瓦集总推挽功率放大器

本文介绍了一种采用推挽式架构的千瓦级非常紧凑的高效固态功率放大器 (SSPA) 模块。该 SSPA 旨在用作 20 kW 回旋加速器的模块化 RF 源，该回旋加速器在低 VHF 频段运行以生产放射性同位素。对于紧凑的设计，集总 $LC$ 为了满足推挽架构的 180° 相移要求，采用巴伦代替传统的铁氧体变压器。采用集总谐波陷阱作为谐波调谐以实现更高的效率。这种实施方式实现了在 90 mm 上实现的超紧凑设计 $\times \,\, 70$ 毫米电路板。通过静态电源电压变化可在降低输出功率的情况下提高效率，在 5 dB 输出功率范围内提供超过 90% 的效率。当应用于整个回旋加速器系统时，这种方法可以实现相当大的节能。所取得的结果表明，所提出的具有漏极电源调制的 SSPA 是一种非常有前途的架构，适用于用于放射性同位素生产的回旋加速器中的高功率射频源。