宽带磁共振T/R开关的设计与实现  

Design of Broadband T/R Switch for Magnetic Resonance

作　　者：姚守权 徐俊成[1] 沈明[1] 胡炳文[1] 宋一桥 蒋瑜[1] YAO Shou-quan;XU Jun-cheng;SHEN Ming;HU Bing-wen;SONG Yi-qiao;JIANG Yu(Shanghai Key Laboratory of Magnetic Resonance,School of Physics and Electronic Science,East China Normal University,Shanghai 200062,China;Department of Radiology,Massachusetts General Hospital,Charleston,Massachusetts 02129,USA)

机构地区：[1]华东师范大学物理与电子科学学院,上海市磁共振重点实验室,上海200062 [2]Department of Radiology,Massachusetts General Hospital,Charleston,Massachusetts 02129

出　　处：《波谱学杂志》2022年第1期115-122,共8页Chinese Journal of Magnetic Resonance

基　　金：上海市科技创新行动计划资助项目(19142202900);国家自然科学基金资助项目(21874045)。

摘　　要：磁共振系统中的发射/接收(transmit/receive,T/R)开关用于收发通路的切换,要求在隔离大功率信号的同时具有较小的插入损耗;另外,在宽带磁共振谱仪中,一般的窄带T/R开关也不再适用.本文基于PIN(positive-intrinsic-negative)二极管设计了工作频率为10~100 MHz的宽带磁共振T/R开关.通过减小电平跳变、优化开关过冲和解决二极管被动导通等问题,获得了插入损耗小于1 dB、大功率信号隔离度大于75 dB、开关时间1μs的整体性能.用本文设计的宽带T/R开关替代一般探头中的窄带T/R开关,在0.5 T核磁共振(NMR)波谱仪上测得了氢核和氟核两个不同频率的磁共振信号,验证了宽带T/R开关的宽带性能.Transmit/receive(T/R)switch is used to switch the transmission and reception channels in nuclear magnetic resonance(NMR)spectrometer,which is required high isolation of high-power signals and low insertion loss of NMR signals.In addition,the general narrowband T/R switch is no longer applicable in broadband magnetic resonance spectrometer.This paper presents a positive-intrinsic-negative(PIN)diode-based T/R switch design with low insertion loss(less than 1 dB),high isolation of high-power signals(more than 75 dB)and short switching time(1μs)in broadband(10~100 MHz).Substituting the broadband T/R switch for the narrowband T/R switch of the general probe,the NMR signals of hydrogen and fluorine nuclei at two different frequencies were measured on a 0.5 T NMR spectrometer,which verified the broadband performance of the T/R switch.

关 键 词：磁共振 射频前端 发射/接收(T/R)开关 宽带 

分 类 号：O482.53[理学—固体物理]