In this study,an X-band standing-wave biperiodic linear accelerator was developed for medical radiotherapy that can accel-erate electrons to 9 MeV using a 2.4-MW klystron.The structure works atπ/2 mode and adopts mag...In this study,an X-band standing-wave biperiodic linear accelerator was developed for medical radiotherapy that can accel-erate electrons to 9 MeV using a 2.4-MW klystron.The structure works atπ/2 mode and adopts magnetic coupling between cavities,generating the appropriate adjacent mode separation of 10 MHz.The accelerator is less than 600-mm long and constitutes four bunching cells and 29 normal cells.Geometry optimizations,full-scale radiofrequency(RF)simulations,and beam dynamics calculations were performed.The accelerator was fabricated and examined using a low-power RF test.The cold test results showed a good agreement with the simulation and actual measurement results.In the high-power RF test,the output beam current,energy spectrum,capture ratio,and spot size at the accelerator exit were measured.With the input power of 2.4 MW,the pulse current was 100 mA,and the output spot root-mean-square radius was approximately 0.5 mm.The output kinetic energy was 9.04 MeV with the spectral FWHM of 3.5%,demonstrating the good performance of this accelerator.展开更多
提出了一种新的RF-CMOS晶体管在片测试结构寄生模型,模型综合考虑了射频/微波条件下RF-MOST器件在片测试结构中的各种寄生效应.模型考虑了PAD-互连金属、互连金属-DUT(device under test)之间的非连续性,对互连金属和基底之间的寄生效...提出了一种新的RF-CMOS晶体管在片测试结构寄生模型,模型综合考虑了射频/微波条件下RF-MOST器件在片测试结构中的各种寄生效应.模型考虑了PAD-互连金属、互连金属-DUT(device under test)之间的非连续性,对互连金属和基底之间的寄生效应单独进行了考虑.通过引入一个新的元件,对PAD结构基底感性损耗进行表征.模型最终应用到采用CSM(Chartered Semiconductor Manufacture Ltd)0.25μm RF-CMOS工艺制造的测试结构寄生效应等效电路建模中,高达40GHz测试和仿真数据验证了模型的良好精度.展开更多
衬底寄生网络建模和参数提取,对RF SOI MOSFET器件输出特性的模拟有着非常重要的影响。考虑BOX层引入的体区和Si衬底隔离,将源、体和衬底短接接地,测试栅、漏二端口S参数的传统测试结构,无法准确区分衬底网络影响。提出一种改进的测试结...衬底寄生网络建模和参数提取,对RF SOI MOSFET器件输出特性的模拟有着非常重要的影响。考虑BOX层引入的体区和Si衬底隔离,将源、体和衬底短接接地,测试栅、漏二端口S参数的传统测试结构,无法准确区分衬底网络影响。提出一种改进的测试结构,通过把SOI MOSFET的漏和源短接为信号输出端、栅为信号输入端,测试栅、漏/源短接二端口S参数的方法,把衬底寄生在二端口S参数中直接体现出来,并开发出一种解析提取衬底网络模型参数的方法,支持SOI MOSFET衬底网络模型的精确建立。采用该方法对一组不同栅指数目的SOI MOSFET进行建模,测量和模型仿真所得S参数在20 GHz频段范围内得到很好吻合。展开更多
Assisted by the bead pull technique,nonresonant perturbation theory is applied for measuring and tuning the field of the linac accelerating structure.The method is capable of making non-touching amplitude and phase me...Assisted by the bead pull technique,nonresonant perturbation theory is applied for measuring and tuning the field of the linac accelerating structure.The method is capable of making non-touching amplitude and phase measurements,real time mismatch feedback and field tuning.Some key considerations of the measurement system and of a C-band traveling-wave structure are discussed,and the bead pull measurement and the tuning of the C-band traveling-wave linac accelerating structure are presented at last.展开更多
大多数无线设备的识别研究都是利用小波变换、傅里叶变换(Fourier transform,FT)和机器学习等方法对已知协议的单一设备进行识别,这些研究中设备种类的多样性不足,并且没有一种方法可以在多个设备同时存在时对它们进行识别。为解决上述...大多数无线设备的识别研究都是利用小波变换、傅里叶变换(Fourier transform,FT)和机器学习等方法对已知协议的单一设备进行识别,这些研究中设备种类的多样性不足,并且没有一种方法可以在多个设备同时存在时对它们进行识别。为解决上述问题,提出了一种基于自相关检验的方法,可以在多个不同协议的设备同时存在时对它们进行识别,并且无论是否已知设备的协议,都可以采用该方法。首先通过通用软件无线电设备(universal software radio peripheral,USRP)监测入侵设备的信道来采集信道信号的基带(in-phase and quadrature,IQ)数据,然后利用自相关检验的方法来提取时域信号数据的周期特征。在室内环境下,对无人机、WiFi路由器、ZigBee传感器3种设备中的两两设备同时存在时进行了30次测试,识别的成功率为100%.展开更多
基金the Key R&D Project of the Ministry of Science and Technology of China(No.2022YFC2402300).
文摘In this study,an X-band standing-wave biperiodic linear accelerator was developed for medical radiotherapy that can accel-erate electrons to 9 MeV using a 2.4-MW klystron.The structure works atπ/2 mode and adopts magnetic coupling between cavities,generating the appropriate adjacent mode separation of 10 MHz.The accelerator is less than 600-mm long and constitutes four bunching cells and 29 normal cells.Geometry optimizations,full-scale radiofrequency(RF)simulations,and beam dynamics calculations were performed.The accelerator was fabricated and examined using a low-power RF test.The cold test results showed a good agreement with the simulation and actual measurement results.In the high-power RF test,the output beam current,energy spectrum,capture ratio,and spot size at the accelerator exit were measured.With the input power of 2.4 MW,the pulse current was 100 mA,and the output spot root-mean-square radius was approximately 0.5 mm.The output kinetic energy was 9.04 MeV with the spectral FWHM of 3.5%,demonstrating the good performance of this accelerator.
基金supported by Program of Shanghai Subject Chief Scientist and Natural Science Foundation of China (key program) (Grant No. 08XD1405400)
文摘Assisted by the bead pull technique,nonresonant perturbation theory is applied for measuring and tuning the field of the linac accelerating structure.The method is capable of making non-touching amplitude and phase measurements,real time mismatch feedback and field tuning.Some key considerations of the measurement system and of a C-band traveling-wave structure are discussed,and the bead pull measurement and the tuning of the C-band traveling-wave linac accelerating structure are presented at last.
文摘大多数无线设备的识别研究都是利用小波变换、傅里叶变换(Fourier transform,FT)和机器学习等方法对已知协议的单一设备进行识别,这些研究中设备种类的多样性不足,并且没有一种方法可以在多个设备同时存在时对它们进行识别。为解决上述问题,提出了一种基于自相关检验的方法,可以在多个不同协议的设备同时存在时对它们进行识别,并且无论是否已知设备的协议,都可以采用该方法。首先通过通用软件无线电设备(universal software radio peripheral,USRP)监测入侵设备的信道来采集信道信号的基带(in-phase and quadrature,IQ)数据,然后利用自相关检验的方法来提取时域信号数据的周期特征。在室内环境下,对无人机、WiFi路由器、ZigBee传感器3种设备中的两两设备同时存在时进行了30次测试,识别的成功率为100%.
