用于磁共振成像的光驱动低功耗低噪声放大器
Optically-powered Low Power Low Noise Amplifiers for MRI
浏览论文内容
中文总结 AI 辅助
研究旨在开发光驱动的低功耗低噪声放大器（LPLNA）用于磁共振成像，采用两级级联放大器设计并在单面PCB实现，相比商用LNA功耗低五倍，在多方面性能相当，证明其用于光驱动射频接收线圈阵列的可行性及应用潜力。
中文摘要 AI 辅助
目的：全光接收线圈可能允许具有大通道数、降低通道串扰和减少电缆杂乱的密集接收器阵列。传统低噪声放大器（LNA）的功率需求对于通过光学手段同时驱动多个线圈过高，因为光电功率转换效率仅约为50%。目标是开发在不影响噪声系数（NF）和增益的情况下具有显著更低功耗的低功耗LNA（LPLNA）。方法：使用与MR兼容的E-pHEMT晶体管将LPLNA设计为两级级联放大器。该设计在单面印刷电路板（PCB）上实现，并与商用LNA比较性能。构建了四通道屏蔽环形谐振器阵列，并评估了信噪比（SNR）、噪声协方差和前置放大器去耦性能。结果：LPLNA的电功耗（40 mW）比商用LNA低五倍，并且在体模测量中提供了相当的SNR。体内实验进一步证实LPLNA在实际MRI条件下可靠运行。此外，四通道接收器阵列测量显示与商用LNA相比SNR相当，平均通道间噪声相关性更低，分别为0.26和0.3。结论：本研究证明了LPLNA用于光驱动射频接收线圈阵列的可行性。LPLNA也可应用于功率受限或远程MRI环境。
英文摘要
Purpose: Fully optical receive coils can potentially allow dense receiver arrays with a large channel count, reduced channel crosstalk, and less cable clutter. The power requirements of conventional low-noise amplifiers (LNAs) are prohibitive for simultaneously driving many coils through optical means, as opto-electric power conversion efficiencies can only reach about 50%. The goal is to develop low-power LNAs (LPLNA) with substantially lower power consumption without compromising noise figure (NF) and gain. Methods: A LPLNA was designed as a two-stage cascaded amplifier using an MR-compatible E-pHEMT (Enhancement-mode Pseudomorphic High Electron Mobility Transistor) transistor. The design was implemented on a single-sided printed circuit board (PCB), and its performance was compared with a commercial LNA. A four-channel shielded loop resonator array was constructed, and the signal-to-noise ratio (SNR), noise covariance, and preamplifier decoupling performance were evaluated. Results: The LPLNA had a five-fold lower electrical power consumption (40 mW) than the commercial LNA and provided comparable SNR in phantom measurements. In vivo experiments further confirmed that the LPLNA operates reliably under realistic MRI conditions. Additionally, four-channel receiver array measurements demonstrated comparable SNR within 2% of the commercial LNA and lower inter-channel noise correlation with 0.26 vs 0.3 on average. Conclusion: This study demonstrates the feasibility of LPLNAs for optically-powered RF receiver coil arrays. The LPLNA could also be applied in power-constrained or remote MRI environments.
