核磁共振波谱仪用射频功率放大器的设计与实现

摘要

介绍了一种应用于核磁共振(Nuclear Magnetic Resonance,NMR)波谱仪的宽频带射频功率放大器的设计与实现,提出了射频功率放大器门控信号的设计,探讨了利用传输线变压器构建功率MOSFET输入输出阻抗匹配网络的方法,该射频功率放大器采用多级驱动结合功率放大的结构,包含2个工作模块和基于宽频带定向耦合器的辅助电路,支持高带和宽带通道的相关实验,将该射频功率放大器应用在自主研发的500 MHz高分辨率液体NMR谱仪上,测量射频功放的上升、下降时间及输出线性度,并对比测试1H和13C NMR标样的信噪比,实验结果证明了该设计的可行性.%The design and implementation of a broadband RF power amplifier used in nu clear magnetic resonance spectrometer were introduced. Based on a two-stage architec ture, the power amplifier was composed of a high frequency module, a broadband mod ule and two directional couplers, to meet various requirements of NMR experiments. The rise time, fall time and power linearity of the power amplifier was measured on a home-built 500 MHz NMR spectrometer. Comparison of NMR sensitivity demonstrated good performance of this power amplifier in common NMR experiments.