High efficiency radiofrequency power amplifier module for parallel transmit arrays at 3 Tesla.
High efficiency radiofrequency power amplifier module for parallel transmit arrays at 3 Tesla.
复制标题
用于 3 特斯拉并行发射阵列的高效射频功率放大器模块。
DOI：
10.1002/mrm.26510
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发表时间：
2017
影响因子：
3.3
通讯作者：
Griswold,MarkA
中科院分区：
文献类型：
--
作者：
Twieg,Michael;Griswold,MarkA
PurposeThe的目的是本研究的目的是开发一种在孔射频（RF）功率放大器（RFPA）模块，具有高功率效率和密度，用于在3 Tesla.MethodsThe模块使用的电流模式D类，S类和E类放大器的组合，基于增强型硅基氮化镓场效应晶体管的并行发射（pTX）阵列。这些放大器一起实现包络消除和恢复，以在宽工作范围内实现高效率的幅度调制。静态非线性和功率效率的模块进行了测量，使用脉冲RF测量超过37 dB的动态范围。热性能也进行了测量，没有强制对流cooling.ResultsThe模块产生的峰值射频功率高达130 W的整体效率为85%。当产生100 W的RF脉冲在占空比为10%，最大结温不超过80 °C，即使没有使用散热器或强制convention.ConclusionThe小尺寸和低成本的模块承诺pTX系统的实施成本较低的线性RFPA位于远程相比。在存在非线性和耦合的情况下，必须对RF输出进行进一步的控制。Magn Reson Med 78：1589-1598，2017。© 2016国际医学磁共振学会。
PurposeThe purpose of this study is to develop an in‐bore radiofrequency (RF) power amplifier (RFPA) module with high power efficiency and density for use in parallel transmit (pTX) arrays at 3 Tesla.MethodsThe modules use a combination of current mode class D, class S, and class E amplifiers based on enhancement‐mode gallium nitride‐on‐silicon field‐effect transistors. Together the amplifiers implement envelope elimination and restoration to achieve amplitude modulation with high efficiency over a wide operating range. The static nonlinearity and power efficiency of the module were measured using pulsed RF measurements over a 37 dB dynamic range. Thermal performance was also measured with and without forced convection cooling.ResultsThe modules produces peak RF power up to 130 W with an overall efficiency of 85%. When producing 100 W RF pulses at a duty cycle of 10%, maximum junction temperatures did not exceed 80 °C, even without the use of heatsinks or forced convection.ConclusionThe small size and low cost of the modules promise lower cost implementation of pTX systems compared with linear RFPAs located remotely. Further work must be done on control of the RF output in the presence of nonlinearities and coupling. Magn Reson Med 78:1589–1598, 2017. © 2016 International Society for Magnetic Resonance in Medicine.