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1.
基于真空二极管设计了一种X波段大功率微波检波器,该检波器主要由真空二极管、BJ-100波导、调谐螺栓、低通滤波器和直流电源组成,其工作频率可根据需要在8.6~9.8GHz范围内调谐。重点阐述该型大功率微波检波器的结构设计、实验室标定及辐射场测量实验结果,研究了不同脉宽和不同灯丝电压与检波特性的依赖关系。实验结果表明:该型检波器具有承受微波脉冲功率高(大于7kW)、响应快(响应时间小于2.0ns)、动态范围大、输出信号幅度高(可达数十V)、不需要同步信号等特点,适用于在高功率微波干扰环境下的单次和高重复频率脉冲功率测量。 相似文献
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获得长脉冲高功率微波(HPM)输出是HPM源技术追求的重要目标之一。从物理机理上分析了影响慢波结构HPM器件实现长脉冲HPM输出的因素,并利用长脉冲脉冲功率源和过模慢波结构HPM器件,开展了X波段长脉冲HPM产生实验。实验中,采用介质-铜阴极,并在慢波结构表面镀Cr,在导引磁场约0.7 T、二极管电压约400 kV、电流约10 kA、束流脉宽200 ns的条件下,获得了功率500 MW、脉宽约100 ns、主模为TM01的X波段长脉冲HPM输出。对实验结果的分析表明,脉冲功率源与HPM器件的阻抗不匹配,是导致HPM器件输出微波脉宽比电子束脉宽短、以及HPM器件输出微波功率效率较低的主要原因。 相似文献
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通过对半导体材料中载流子迁移率的特性分析,在原HPM探测器的基础上,提出了探测器中半导体传感器的新设计,使探测器的检测灵敏度提高一个量级;同时研制成功S波段HPM探测器。在传感器的加工方面采用了新的工艺,并对电源进行了改进,使之功能完善、使用简单、具有实用性。其电源偏压在40V时,X波段的探测器在60kW时输出检测脉冲信号幅度高达9V,S波段的探测器在600kW时输出检测脉冲信号幅度高达10V,可适用于10~500ns脉宽的HPM功率测量。 相似文献
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主要给出了波导型的X波段大功率微波探测器的结构、标定方法和标定结果。该新型大功率微波探测器具有承受微波峰值功率高(可达100 kW),时间响应快(响应时间小于2.0 ns),不需要同步信号,抗干扰能力强等特点。根据不同的需要,可以制作成波导型和同轴型的大功率微波探测器。波导型探测器由热离子二极管、标准波导、滤波器和外电路组成,其工作频率范围为波导的工作频率范围;而同轴型探测器由热离子二极管、同轴波导,滤波器和外电路组成,可以宽带使用。标定结果表明该探测器很适合高功率微波峰值功率测量,尤其是在强电磁干扰环境和高重频微波脉冲条件下的测量,为解决功率测量不准的技术难题提供一种有效的技术手段。 相似文献
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M. Wang S. Zhang Y. Tang L. Xu Y. Wang C. Zhao Y. Hang W. Chen 《Applied physics. B, Lasers and optics》2011,104(4):829-833
An efficient laser diode end-pumped continuous-wave (CW) and AO Q-switched laser of Nd:LiLuF4 crystal with dual central wavelengths of 1053.1 and 1054.7 nm is reported for the first time. The maximum CW output power
of 6.22 W was obtained at absorbed pump power of ∼14.6 W with the output transmission of 2%. The optical conversion efficiency
is ∼43%, corresponding to a slope efficiency of about 48% with respect to the absorbed pump. For the Q-switched operation,
the shortest pulse width of 17 ns was obtained at the pulse repetition frequency (PRF) of 0.5 kHz, resulting in a pulse energy
of 2.24 mJ and peak power of 131.8 kW. 相似文献
6.
V. N. Dobrovolsky F. F. Sizov Y. E. Kamenev A. B. Smirnov 《Opto-Electronics Review》2008,16(2):172-178
A model of semiconductor hot electron bolometer (SHEB), in which electromagnetic radiation heats only electrons in narrow-gap
semiconductor without its lattice slow-response heating, is considered. Free carrier heating changes the generation-recombination
processes that are the reason of semiconductor resistance rise. It is estimated, that Hg0.8Cd0.2Te detector noise equivalent power (NEP) for mm and sub-mm radiation wavelength range can reach NEP ∼10−11 W at Δf = 1 Hz signal gain frequency bandwidth. Measurements performed at electromagnetic wave frequencies v = 36, 39, 55,
75 GHz, and at 0.89 and 1.58 THz too, with non-optimized Hg0.8Cd0.2Te antenna-coupled bolometer prototype confirmed the basic concept of SHEB. The experimental sensitivity Sv ∼2 V/W at T = 300 K and the calculated both Johnson-Nyquist and generation-recombination noise values gave estimation of
SHEB NEP ∼3.5 × 10−10 W at the band-width Δf = 1 Hz and v = 36 GHz. 相似文献
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介绍了一种微秒长脉冲有磁场的真空二极管界面的设计和实验结果。采取了三种措施来抑制沿面闪络:一是阴极电子束挡板,用来拦截来自阴极和电子束漂移管的回流电子束;二是接地屏蔽板,使电场等势线和界面成约45°角,使阴极三结合点处发射的电子远离绝缘板;三是降低阴极三结合点处的场强,并使用一悬浮电位的金属环阻止电子倍增过程。计算了二极管内电场、磁场分布和电子束的运动轨迹并据此优化了真空界面的结构,实验验证了该二极管真空界面可以在400 kV、800 ns条件下正常工作,可以支持长脉冲高功率微波器件的研究。 相似文献
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基于PIN二极管电热自洽耦合模型,构建了两级PIN限幅器高功率微波(HPM)效应电路模型。根据模拟模型设计加工了两级限幅器实验样品,限幅器输入、输出特性注入实验数据与模拟计算结果基本一致,验证了多级限幅器模型的有效性,表明该多级PIN限幅器模型能够应用于HPM效应模拟。针对不同HPM波形参数进行了HPM效应模拟,计算结果表明:随着注入功率的增大,脉宽增宽,前级厚I层PIN二极管结温升比后级薄I层PIN二极管结温升要高,因此厚I层PIN二极管更易受到损伤;而频率和前沿参数对结温升影响较小。 相似文献
13.
Spatial and temporal gain profiles as well as the peak net gain at 193 nm have been measured in X-ray preionized discharges
excited by a single pulse electrical system working in the charge transfer mode. Ar- and F2-containing laser gas mixtures with He or Ne as a buffer gas have been used. With a pumping pulse duration of ∼ 100 ns (FWHM)
and a specific peak power deposition of ∼ 1 MW cm-3 bar-1 in a gas mixture containing F2 : Ar : He (0.1%:5%:94.9%), at 2 bar total pressure, a very high peak net gain coefficient of ∼ 30% cm-1 was measured in the gas discharge. The FWHM of the gain waveform was ∼ 60 ns.
PACS 42.55.Lt; 42.60.Lh; 52.80.-s 相似文献
14.
We present in this paper a highly stable and efficient KTP-based intracavity optical parametric oscillator with a diode-end-pumped
Nd:YVO4/Cr:YAG passively Q-switched laser. At the incident diode pump power of 4 W, the signal (1.57 μm) and idler (3.29 μm) average
output powers up to 580 and 100 mW, respectively, have been achieved. The corresponding conversion efficiency from the input
diode pump power to the output signal power is 14.5%, while that to the total OPO output (signal+idler) reaches 17%. To the
best of our knowledge, these are the highest conversion efficiencies reported to date. After more than four hours of investigation,
the OPO power stability better than 2% has been obtained. In addition, efficient cavity dumping of the IOPO has inevitably
led to the short pulse duration (1.6 ns) and high peak power output (8.3 kW) at the signal wave. Additionally, the amplitude
and repetition rate fluctuations of the signal pulses are well within 5%.
PACS 42.55.Xi; 42.60.Gd; 42.60.Lh; 42.65.Yj 相似文献
15.
为了探索短电脉冲产生高功率微波技术,采用理论和粒子模拟方法分析了短电脉冲(脉宽不大于30ns)驱动S波段相对论扩展互作用腔振荡器(REICO)产生高功率宽谱的技术可行性,开展了原理性的实验验证。采用Marx发生器产生的前沿15ns、后沿30ns、电压560kV、束流2.8kA的类三角形电子束脉冲激励REICO,模拟产生了410MW、脉宽8ns、相对瞬时带宽2.7%的微波,实验输出了160MW、脉宽10ns、中心频率2.75GHz、瞬时相对带宽2.8%的高功率微波。 相似文献
16.
高功率微波(HPM)电磁脉冲对引信辐照实验的数据分析是研究其电磁效应中的一个重要问题,数据分析的主要困难在于HPM电磁效应数据的高维复杂性。通过聚类算法设计,采用模糊C均值聚类(FCM)算法对某无线电引信的高功率微波电磁效应数据进行分析处理,利用其类内相似和类间相异的原则,经迭代运算,实现HPM对无线电引信效应数据的脉宽、峰值功率、功率密度等参数间的识别和分类。结果表明:采用FCM算法能够得到HPM对某引信的最佳聚类中心,即致使引信失效的最佳干扰阈值,证明了算法的有效性。 相似文献
17.
The mechanism of generation of terahertz radiation upon irradiation of a target by short (∼ 0.1 ns) high-intensity laser pulses
(I ∼ 1018−1019 W cm−2) is investigated by numerical simulation using the relativistic electromagnetic PIC code. The interaction of such a pulse
with the target, a plasma is formed on it. Electrons emitted from the plasma form a virtual cathode whose oscillations are
determined not only by their self-field, but also by the field of ions of the plasma. Generation occurs in the terahertz frequency
range with the efficiency thrice as high as in the absence of ions (i.e., with traditional reditron generation mechanism).
The explanation for this effect is also given. 相似文献
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Optical interference fringes due to unwanted etalons are often the limiting uncertainty in diode laser spectroscopic trace gas measurements. Temporal variations in the fringe spacings, phases, and amplitudes introduce systematic baseline changes that limit useful signal averaging times to ∼1000 s, and constrain minimum detectable absorbances to between one and three orders of magnitude worse than the fundamental limiting noise sources (shot noise and/or detector thermal noise). We describe an adaptive numerical filtering method based on singular value decomposition (SVD) that shows, for the system studied, a fivefold reduction in baseline drift due to unwanted etalons over a one-week-measurement period. The adaptive algorithm is fast (<1 ms per computation), robust, and uses linear methods. It is computationally equivalent to principal component analysis (PCA). The test system was acetylene detected using a near-infrared telecommunications laser operating at 6541.96 cm-1. The gas detection limit was 20 ppb (1σ) over the one-week measurement. PACS 07.05.Kf; 07.07.Df; 07.60.-j; 42.60.-v; 42.62.-b; 42.62.Fi 相似文献
20.
S. Latif S. E. Kocabas L. Tang C. Debaes D. A. B. Miller 《Applied Physics A: Materials Science & Processing》2009,95(4):1129-1135
We have studied the response of CMOS compatible detectors fabricated in a silicon-on-sapphire (SOS) process, operated under
short pulse excitation in the blue. These high speed, low capacitance detectors would be suitable for very precise, surface-normal
clock injection with silicon CMOS. We characterize the capacitance of the detector structure through a combination of experimental
techniques and circuit-level and electromagnetic simulations. The transit-time-limited response of the detectors is validated
through pump–probe experiments. Detector response times of ∼35 ps have been measured, and devices have capacitance as low
as ∼4 fF. 相似文献