300GHz超导SIS接收机系统的设计与构建

超导SIS(Superconductor-Insulator-Superconductor)混频技术是新兴的低噪声检测技术.其卓越的低噪声性能已使其成为毫米波和亚毫米波频段灵敏度最高的谱线接收设备,接收机的自动控制和稳定性有更高的要求,研制能够长期稳定工作的接收机有很重要的意义.本文主要讨论了我们自行研究设计工作在4K温度,准光学系统的毫米波超导SIS接收机的组成部件,根据我们制备的超导SIS隧道结器件的特性指标,计算设计了300GHz波段的超导接收机天线和结的集成芯片.     

140 GHz回旋管准光模式变换器的设计（英）

针对一种由Denisov型辐射器和第一面镜为准抛物镜的四级反射镜面系统组成的准光模式变换器开展了详细的研究和设计。利用耦合模理论和矢量绕射理论设计了波纹波导准光模式变化器,通过编写仿真程序进行数值优化完成了140 GHz,TE28,8回旋管准光模式变换器的设计。仿真结果表明,抛物面反射镜的焦距对矢量高斯效率影响较大,输出窗口处得到了较好的高斯波束,标量高斯效率达到98%,矢量高斯效率达到90%。     

110GHz回旋管Denisov型准光模式变换器的研究与设计

对一种由Densiov型辐射器和四面反射镜面系统组成的准光模式变换器开展了详细的研究和设计。采用几何光学理论,分析了Denisov型辐射器的工作原理,推导了模式叠加形成高斯分布的过程。基于耦合模理论,提出了辐射器波纹波导的设计方法。针对110GHz,TE22,6模回旋管的具体参数设计和优化了辐射器和镜面系统,编写仿真程序,对波导切口处辐射场和镜面散射场进行数值模拟。计算结果表明,输出窗口处得到较好的高斯波束,高斯效率达到95.8%,功率转换效率为94.7%。     

110 GHz回旋管Denisov型准光模式变换器的研究与设计

对一种由Densiov型辐射器和四面反射镜面系统组成的准光模式变换器开展了详细的研究和设计。采用几何光学理论,分析了Denisov型辐射器的工作原理,推导了模式叠加形成高斯分布的过程。基于耦合模理论,提出了辐射器波纹波导的设计方法。针对110 GHz,TE22,6模回旋管的具体参数设计和优化了辐射器和镜面系统,编写仿真程序,对波导切口处辐射场和镜面散射场进行数值模拟。计算结果表明,输出窗口处得到较好的高斯波束,高斯效率达到95.8%,功率转换效率为94.7%。     

基于半导体光放大器垂直双泵浦对偏振复用正交相移键控信号波长变换的性能研究

针对偏振复用相位调制信号的全光波长变换特性问题,基于半导体光放大器中四波混频效应,建立了对偏振复用正交相移键控信号的全光波长变换理论模型.根据理论分析,建立了仿真系统,仿真结果表明:泵浦光与信号光之间的频率间隔、偏振复用信号中的一个信号与一号泵浦光的偏振夹角对系统转换效率和信号质量有影响;波长转换过程中交叉相位调制产生的相位噪音会对信号质量有影响,且当泵浦光功率较大、泵浦光功率远大于信号光功率时,交叉相位调制效应的影响较小,仿真结果与理论分析一致.本文研究方法和相关结论对其它偏振复用信号基于半导体光放大器四波混频效应的波长变换研究有一定的参考价值.     

毫米波生物效应聚焦装置的设计

采用喇叭天线与透镜相结合的准光技术方案,设计了毫米波生物效应聚焦装置,其频率达到95 GHz,辐射功率达GW级。毫米波辐射源传输到波纹喇叭天线产生的波束经透镜变换得到所需的高斯波束,实现波束能量的汇聚。在毫米波辐射源功率为W级的条件下,该装置的焦斑功率密度达到0.01～2 W·cm-2,焦斑面积为0.8～30 cm2。该实验装置在毫米波生物效应实验中已得到成功应用。     

毫米波生物效应聚焦装置的设计

 采用喇叭天线与透镜相结合的准光技术方案,设计了毫米波生物效应聚焦装置,其频率达到95 GHz,辐射功率达GW级。毫米波辐射源传输到波纹喇叭天线产生的波束经透镜变换得到所需的高斯波束,实现波束能量的汇聚。在毫米波辐射源功率为W级的条件下,该装置的焦斑功率密度达到0.01～2 W·cm^-2,焦斑面积为0.8～30 cm²。该实验装置在毫米波生物效应实验中已得到成功应用。     

新颖的PPLN电光开关

在分析基于级联二阶非线性效应的准相位匹配周期极化铌酸锂(PPLN)波导全光波长变换器的有关参量容限的基础上,提出PPLN波长变换器的电光调控设想,并给予简要论证,论证结果是可行的,从而可实施电控调谐来自动补偿其失配,进而也可实现光开关的功能 关键词： 准相位匹配 周期极化铌酸锂 波长变换 光开关 电光效应调控     

Ka波段高功率斜角弯头的设计

介绍了一种基于准光技术的高功率斜角弯头的设计方法,可实现圆波导TE0m模式的高效转弯传输。使用模式变换器将工作模式TE0m转换成锥形高斯模,经过转弯后,锥形高斯模被重新转换成工作模式。这种锥形高斯模可以减少波束在镜面的衍射,从而实现工作模式的高效率转弯传输。基于这一方法,设计了工作在Ka波段、工作模式TE01的MW级波导斜角弯头。HFSS计算结果表明: 在8%的带宽内,传输效率大于98%。     

Ka波段高功率斜角弯头的设计

介绍了一种基于准光技术的高功率斜角弯头的设计方法,可实现圆波导TE0m模式的高效转弯传输。使用模式变换器将工作模式TE0m转换成锥形高斯模,经过转弯后,锥形高斯模被重新转换成工作模式。这种锥形高斯模可以减少波束在镜面的衍射,从而实现工作模式的高效率转弯传输。基于这一方法,设计了工作在Ka波段、工作模式TE01的MW级波导斜角弯头。HFSS计算结果表明： 在8%的带宽内,传输效率大于98%。     

A 385–500 GHz SIDEBAND-SEPARATING (2SB) SIS MIXER BASED ON A WAVEGUIDE SPLIT-BLOCK COUPLER

We have developed a 385–500 GHz sideband-separating (2SB) mixer, which is based on a waveguide split-block coupler at the edge of the H-plane of the 508 μm × 254 μm (WR 2.0) waveguide, for the Atacama Large Millimeter/submillimeter Array (ALMA). An RF/LO coupler, which contains an RF quadrature hybrid, two LO couplers, and an in-phase power divider, was designed with the issue of mechanical tolerance taken into account. The RF/LO coupler was measured optically with a microscope and electrically with a submillimeter vector network analyzer. The image rejection ratio (IRR) and the single-sideband (SSB) noise temperature of the receiver using the RF/LO coupler have also been measured. The IRR was found to be larger than 8 dB and typically ∼ 12 dB in the 385–500 GHz band. The SSB noise temperature of this receiver is 80 K at the band center, which corresponds to 4 times the quantum noise limit (hf/k) in SSB, and 250 K at the band edges. An erratum to this article can be found at     

A Fixed-Tuned W-Band Waveguide SIS Mixer with 4.0-7.5 GHz IF

The design and performance of a fixed-tuned W-band SIS mixer with a wide band IF of 4.0-7.5 GHz is presented. Waveguide-to-stripline transition of the SIS mixer is designed using the lumped-gap-source port provided by HFSS^TM. Measured receiver noise temperature is less than 25 K in the frequency range of 95-120 GHz, with a minimum value of around 19 K achieved. Mixer noise temperature is determined to be about 8.5 K, which is around twice the quantum limit (i.e., 2hw/k). In spite of the high IF frequencies (f ₀ = 6 GHz), the performance of the SIS receiver is comparable or even superior to those of the best mechanically-tunable waveguide SIS receivers at low IF frequencies (f ₀ = 1.5 GHz). This result suggests that it is easy to design waveguide-to-stripline transitions without scale-model measurements.     

油气混输中掺混器的研究与改进

在常用的油气混输工艺中,从油井开采出的油和气经分离处理后重新掺混,再由混输泵加压后通过管道运送或由气泵、液泵分别加压,掺混后运送。为了避免引起混输管道的大幅振动以及对泵造成损坏,混输工艺一般都要求掺混器出口不能出现大规模气态段塞现象。在本文当中,我们对T形管掺混器、文氏管掺混器进行了实验研究,并提出了能对进入掺混器的气体质量流量进行控制的拉伐尔喷管掺混器设计方法。试验结果表明,拉伐尔喷管掺混器可以非常方便地根据需求控制掺混器下游流态。这一特性使得拉伐尔喷管掺混器在石油、化工领域具有非常广泛的应用前景。     

A Low-Noise 230 GHz SIS Receiver for Radio Astronomy Employing Untuned Nb/AlOx/Nb Tunnel Junctions

A heterodyne receiver based on a 1/3 reduced height rectangular waveguide SIS mixer with two mechanical tuners has been built for astronomical observations of molecular transitions in the 230 GHz frequency band. The mixer used an untuned array (R_nC_j3, R_n70 ) of four Nb/AIOx/Nb tunnel junctions in series as a nonlinear mixing element. A reasonable balance between the input and output coupling efficiencies has been obtained by choosing the junction number N=4. The receiver exhibits DSB (Double Side Band) noise temperature around 50 K over a frequency range of more than 10 GHz centered at 230 GHz. The lowest system noise temperature of 38 K has been recorded at 232.5 GHz. Mainly by adjusting the subwaveguide backshort, the SSB (Single Side Band) operation with image rejection of 15 dB is obtained with the noise temperature as low as 50 K. In addition, the noise contribution from each receiver component has been studied further. The minimum SIS mixer noise temperature is estimated as 15 K, pretty close to the quantum limit v/k11 K at 230 GHz. It is believed that the receiver noise temperatures presented are the lowest yet reported for a 230 GHz receiver using untuned junctions.     

S波段高温超导滤波器的研制

本文采用全波电磁仿真分析方法,在YBCO/LAO/YBCO双面超导薄膜(介电常数为23.5)上设计并研制了具有内部耦合的8级高温超导(HTSC)小型化多曲折滤波器,在77K时基本未经调谐测得其中心频率为3.6GHz,带宽为200MHz,通带内插入损耗<0.2dB,回波损耗优于-20dB,带外抑制优于50dB.本文研制的S波段高温超导滤波器在移动通讯和卫星通讯领域具有广泛的应用前景,测试结果表明,滤波器具有较为优异的性能.     

ZrO_2的掺杂对于单畴YBCO超导块材的影响

研究了在Y211中掺入ZrO2对于用顶部籽晶熔渗方法制备YBCO块材的影响,以及不同掺杂比例对于样品表面形貌和磁悬浮力的影响.实验表明,随着ZrO2掺杂量的增加,样品的磁悬浮力有增大的趋势.这种现象可能是由于ZrO2的掺杂在样品中形成了磁通钉扎中心,有效的提高了超导体的物理性能.     

高阻抗伏特计的设计

阐述自制高阻抗伏特计的电路设计原理与组装技术。     

CONCEPTUAL DESIGN STUDIES OF AN 84 GHz, 500 kW, CW GYROTRON

The feasibility of an 84 GHz, 500 kW, CW gyrotron for ECRH on an experimental tokamak will be presented in this paper. Mode competition and mode selection procedures are carefully investigated by considering various candidate modes and the TE_10,4 mode is chosen as the operating mode. A conventional cylindrical cavity resonator with weak input and output tapers and parabolic roundings is considered for interaction studies. Self-consistent, both single mode and time-dependent, calculations are carried out and power and efficiencies are computed for a typical set of beam parameters. The results show that an output power of well over 500 kW, CW and efficiency around 40% can be reached without a depressed collector.     

光学实验室网络教学平台的设计

传统的多媒体课件正在受到网络使用环境挑战，取而代之将是基于网而设计的多媒体教学平台。利用FIASH、Cult3D等技术开发的基于网络环境的虚拟实验室案的提出将为大学物理实验开辟一个崭新的多媒体教学方案。