低场磁共振系统的低噪声前置放大器研究设计  

Low Noise Pre-Amplifier Design for Low-Field Magnetic Resonance Systems

作　　者：亢科 徐雅洁[2] 张闻文[1] 杨晓冬[2] KANG Ke;XU Ya-jie;ZHANG Wen-wen;YANG Xiao-dong(School of Electronic and Optical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China;Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, China)

机构地区：[1]南京理工大学电子工程与光电技术学院,江苏南京210094 [2]中国科学院苏州生物医学工程技术研究所,江苏苏州215163

出　　处：《波谱学杂志》2017年第3期383-395,共13页Chinese Journal of Magnetic Resonance

基　　金：中国科学院科研装备研制资助项目(YZ201445)

摘　　要：噪声前置放大器是磁共振射频接收子系统中的重要组件,它的性能优劣直接决定了最终磁共振图像的好坏.目前市场上的低噪声前置放大器大多基于中高场磁共振系统开发,而针对低场磁共振系统的很少;另外,商用低场磁共振系统的低噪声前置放大器价格相对较贵,并且多采用两级放大结构,结构复杂、调试难度大、成本相对较高.在此背景下,针对0.5 T低场磁共振设备利用Keysight公司的先进设计系统(ADS)软件对低噪声前置放大器进行研究设计,采用一级放大结构,探索电路设计与布局对放大器性能的影响.实测结果表明自主设计的低噪声前置放大器在21 MHz共振频率附近噪声系数为0.5 dB左右,增益达到了30 dB,能够满足低场磁共振应用的要求.Low noise pre-amplifier is an important component in the radiofrequency(RF)receiving subsystem of magneticresonance systems.The performance of pre-amplifier determines the quality of the final images directly.Currently,lownoise pre-amplifiers on the market mostly are designed for high-field magnetic resonance systems.Few such low noisepre-amplifiers were designed specifically for low-field magnetic resonance systems.Moreover,commercially-available lownoise pre-amplifiers are relatively expensive,and most of the designs use a complicated two-stage amplification structure.For these reasons,a low noise pre-amplifier with only one-stage amplification structure was developed in this study for0.5T low-field magnetic resonance systems using the advanced design system(ADS)software.The circuit design andlayout effects were presented.Experimental measurement showed that the noise figure of on-resonance frequency21MHzwas about0.5dB,and a gain of30dB was achieved.

关 键 词：低场磁共振系统 低噪声 高增益 前置放大器 

分 类 号：O482.53[理学—固体物理]