共查询到17条相似文献,搜索用时 109 毫秒
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本文描述了8mm波段超外差前馈跟踪系统的原理及在聚变等离子体实验装置上的应用。它适用于在强的辐射条件下的微波干涉、微波散射及微波传输等实验。具有很高的抑制辐射噪声干扰的能力。本文详细介绍了此系统小型磁镜实验装置MM-2中等离子体密度的测量方法,它有效地克服了由于该装置中由同步辐射造成的强的干扰,信噪比大于45分贝。该系统优于其他诊断系统的特点在本文中也进行了讨论。 相似文献
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介绍了核聚变装置HL-2A托克马克中各种微波技术在等离子体诊断中的应用。说明了各种诊断的基本原理、电路安排以及在放电中的测量结果。电子回旋辐射(ECE)主要用来测量主等离子体电子温度及其扰动分布。测量的时间分辨率可以达到4m s(扫频)或者1μs(单频),空间分辨率为3 cm。电子温度的测量范围为10 eV~10 kev。微波反射用于等离子体密度分布、等离子体旋转及等离子体密度扰动等方面的测量及研究,在测量密度分布时的时间分辨为1m s,空间分辨大约1 cm左右。微波干涉诊断用来测定偏滤器中等离子体的平均密度变化,时间分辨率为0.1m s。 相似文献
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高功率微波极易引起大气击穿, 而伴随产生的等离子体将对微波传播特性产生很大的影响.基于电子流体模型, 研究了一个大气压下110 GHz高功率微波在大气击穿等离子体中的传输、反射和吸收特性.模拟结果表明, 大气击穿等离子体结构在空间呈丝状分布, 其与实验现象符合得很好; 由于大气击穿等离子体是时变的, 其对微波的反射和吸收也是时变的; 随着时间的推移, 等离子体吸收功率逐渐增加直至达到饱和水平, 且其远大于微波反射功率; 当减小入射电场时, 等离子体对微波的反射变得更低.将110 GHz微波击穿阈值的模拟结果与实验数据进行对比, 发现两者吻合得很好. 相似文献
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电子束与等离子体互作用产生的宽带微波辐射 总被引:1,自引:0,他引:1
近年来,电子束与等离子体互作用产生高功率宽带微波辐射,由于其具有可调谐等优点而受到国际上普遍关注,这一互作用过程的辐射机制目前大致分为等离子体辐射和电子束辐射两大类,本文在简介了有关实验情况后,对几种辐射机制,包括逆Compton散射,孤立子场中群聚电子的辐射,非线性等离子体电流引起的辐射等作了评述。 相似文献
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一、概述微波遥感是一门具有广泛用途的微波探测新技术,它可以在遥远的距离之外不必直接接触被测物体就能测定物体的特性及其变化规律.而用来探测和收集被测物体的微波辐射或反射(散射)能量的设备,称为微波遥感器.微波散射计是一种有源的微波遥感器,也称为校准的雷达.主要用来探测并测定被测物体的微波背向散射能量,从而判别被测物体的种类,并推断其不同性质及其变化规律. 相似文献
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薄膜混合电路中有机薄膜厚度的快速测定 总被引:1,自引:0,他引:1
介绍了一种无损、快速、准确测定有机薄膜厚度的新方法-FT-IR反射-干涉光谱法.对测厚的原理进行了分析,将此方法用于薄膜微波电路生产中光刻胶和聚酰亚胺厚度的测定,并与传统的用台阶仪测厚方法进行比较. FT-IR反射-干涉光谱法更方便、快捷、更准确,避免了光刻的过程和光刻显影过程中显影液对膜厚的减损,以及台阶测厚仪本身可能造成的测量误差. 相似文献
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目前的微波辐射测量成像系统在一次观测中所采集的数据量大,基于奈奎斯特空间采样及常规微波辐射图像重构方法难以实现高分辨率要求。该文针对微波辐射干涉测量在频域中进行,采用傅里叶最优随机抽取的超稀疏干涉测量(低于奈奎斯特采样)对微波辐射图像进行线性压缩投影,降低数据采样。考虑微波辐射图像在总体差分域和小波中都具有可压缩特性,提出总体差分和小波混合正交基的K-SVD字典学习微波辐射图像重构模型,利用Bregman和交替迭代算法求解该模型,重构线性压缩投影信息从而获得微波辐射图像。仿真实验表明,该文提出的算法在微波辐射图像重构效果、噪声稳定性上优于DLMRI算法和GradDLRec算法。 相似文献
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G. P. Kuz’min I. M. Minaev K. Z. Rukhadze V. P. Tarakanov O. V. Tikhonevich 《Journal of Communications Technology and Electronics》2012,57(5):536-542
A reflector plasma array antenna is investigated. A plasma array with a controlled pattern is created with the help of a discharge
creeping over a dielectric surface. The scattering microwave radiation pattern is calculated for the vertical and horizontal
polarizations of the radiation incident on the plasma array. 相似文献
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Microwave holography is an extension of the optical holography to the microwave field. In fact, by using a well-known characteristic of the holographic process, it is possible to record the hologram at frequencies very far from the optical region (microwave) and to reconstruct a visible image by laser light. This paper describes the experimental apparatus and the technique used for obtaining a satisfactory optical wave reconstruction from microwave holograms. The resolving power of the system which was experimentally tested, and visible images of microwave transparencies and of a back scattering object are given. As an alternative application of the microwave holography together with the optical wave reconstruction, in this paper, extension of holographic interferometry to the microwave region is suggested, and the visible image of a deformed object crossed by fringes due to microwave interference is also shown. This technique can find applications, for instance, in the mapping of the earth's deformations or in that of the tides. Different aspects of the microwave holographic interferometry have been also discussed. 相似文献
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D. A. Usanov S. S. Gorbatov 《Journal of Communications Technology and Electronics》2008,53(3):290-294
It is found that, in a gapped-post-adjacent-plunger system, reflection of microwave radiation occurs. This reflection is dependent on the magnitude and direction of the magnetic field. It is indicated that this phenomenon can be used for the development of tunable microwave cavities. 相似文献
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Hagness S.C. Taflove A. Bridges J.E. 《Antennas and Propagation, IEEE Transactions on》1999,47(5):783-791
We are investigating a new ultrawide-band (UWB) microwave radar technology to detect and image early-stage malignant breast tumors that are often invisible to X rays. We present the methodology and initial results of three-dimensional (3-D) finite-difference time-domain (FDTD) simulations. The discussion concentrates on the design of a single resistively loaded bowtie antenna element of a proposed confocal sensor array. We present the reflection, radiation, and scattering properties of the electromagnetic pulse radiated by the antenna element within a homogeneous, layered half-space model of the human breast and the polarization and frequency-response characteristics of generic tumor shapes. We conclude that the dynamic range of a sensor array comprised of such elements in conjunction with existing microwave equipment is adequate to detect small cancerous tumors usually missed by X-ray mammography 相似文献