共查询到19条相似文献,搜索用时 125 毫秒
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金刚石材料具有低的介电常数、小的微波损耗、良好的导热性能,成为太赫兹电真空器件发展过程中非常有研究价值和应用价值的材料。它可以作为输能窗的介质窗片和高频结构的介质支撑材料。本文介绍了微波等离子体化学气相沉积(MPCVD)金刚石材料在太赫兹电真空器件中的具体应用实例,以及在W波段行波管中的实际应用情况,包括MPCVD金刚石的制备过程,及其与金属材料的封接工艺。研制出的W波段金刚石窗冷测结果显示其在75 GHz-110 GHz频段内性能良好:驻波系数(VSWR)≤1.5,传输损耗≤0.5 dB。这种窗已经成功用于W波段折叠波导连续波与脉冲行波管中。 相似文献
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提出一种铁氧体金属化方法,解决了微波介质器件中铁氧体容易脱落的问题,为微波介质器件的发展开辟了一个新的方向。 相似文献
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利用基于有限元方法的COMSOL软件,仿真研究了由等离子体放电微管阵列组成的一维光子晶体的微波传输特性,讨论了微管中等离子体密度和阵列周期结构参数对一维等离子体光子晶体微波传输特性的调控作用。研究结果为微波段多通道滤波器以及动态微波器件的设计和制作提供了理论参考。 相似文献
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夏先齐 《固体电子学研究与进展》1984,(4)
聚酰亚胺是一种高分子聚合物材料。它的组分及结构使其具有比SiO_2等无机介质更优越的介质特性与热特性,且刻蚀方法简便。在微波GaAs FET中作表面钝化、双层布线隔离介质应用时明显提高了器件可靠性,尤其改善了塑料封装器件的防潮性能,简化了FET工艺步骤。 相似文献
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王殿宏 《内蒙古广播与电视技术》1998,(4):20-21
1引言介质谐振器是一种高介电常数(v=36~70)、低损耗的介质材料制成的谐振器,它具有体积小、在微波电路中应用简单、性能优良等特点。应用介质谐振器(DR)可以设计出一种频率稳定性好、Q值高和噪声低的新型微波振荡源,这种振荡源称为介质谐报器振荡器(DRO),其主要优点是频率稳定度高、噪声小、体积小、结构简单、价格低、对机械振动和电源瞬变过程不敏感,因而广泛应用于通信系统、雷达信标、电子对抗接收机、导弹应答机、专用测试设备以及气象雷达设备中。2微波介质振荡器工作原理介质谐振器与覆盖微波频数的各种有源器件一起… 相似文献
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Cantor分形R分集分层介质是一种自相似结构,这种结构在光学、量子力学领域很可能有重要应用。本文根据时域信号流图技术研究这种分形结构的逆散射方法,即利用已知的反射系数谱重建Cantor分形的维数及其自相似结构。文中给出了具体重建实例。 相似文献
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Yin He-Jun Lu Bao-Wei Song Wen-Miao Yin Yuan-Zhao 《Journal of Infrared, Millimeter and Terahertz Waves》1994,15(8):1421-1431
In this paper, we put forward a new version of Cantor fractal multilayers, which are nonlinear medium, and investigate its properties of reflection and transmission when a plane wave is obliquely incident upon it. A new exact self-similarity algorithm that make use of the self -similarity of these structure are developed. The results for different stages of fractal growth within the first-order nonlinear approximation are found. Compared with the traditional chain-matrix approach, the scheme provides the reflection and transmission coefficients for any stage (S) with much less calculation time on a personal computer. 相似文献
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Wavelet analysis of transients in fractal superlattices 总被引:1,自引:0,他引:1
Fractal superlattices are designed by alternating dielectric layers according to an iterative fractal process. The discrete self-similarity of such stratified structures can be remotely detected from interrogation by an incident pulse. In this paper, the impulse response of one-dimensional Cantor superlattices is computed and the wavelet transform is applied to the reflected signal in order to explore its temporal distribution of singularities. For a sufficiently narrow pulse, the skeleton of the wavelet-transform modulus-maxima exhibits a hierarchical structure that makes apparent the iterative process governing the construction rule of the interrogated fractal superlattice and its geometry. In the reflected signal, such hierarchy reveals the existence of singularities that are distributed on the governing Cantor set. Finally, the similarity dimension is extracted from reflection data and a strategy for estimating the stage of growth is developed 相似文献
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Zhong-Yin Xiao Zi-Hua Wang 《Journal of Infrared, Millimeter and Terahertz Waves》2009,30(10):1038-1043
In this paper, the microstrip line with fractal Cantor distributing substrates is investigated. Transmission matrix method
is used to calculate the transmittance and reflectance. Comparing with periodic distributing substrates, the microstrip line
with fractal Cantor distribution shows sharp resonances inside band gap. The resonances in somewhere split and form more peaks
with increase of the number of generation. Based on the microstrip line with Cantor substrates, a novel bandpass filter is
proposed. The filter has 8.8 % 3dB bandwidth and two transmission zeros, 0.27dB insertion loss. The effect of width of microstrip
line and thickness of substrate on the filter properties are discussed too. 相似文献
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We compare, in this paper, the far field radiated by two fractal distributions of current. The first one is obtained by a fractal cut following the Cantor arrangement, the second one keeps the length of each previous current element, but modifies the distance between the elements which is now taken as a constant. We establish the analytical formulations of the far field at any step n of the Cantor set. Then, we extract the array factor and we analyse and compare the following properties : convergence of the radiation pattern, wide of the main lobe, side lobes level and directivity. 相似文献
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An efficient recursive procedure for evaluating the impedance matrix of linear and planar fractal arrays 总被引:1,自引:0,他引:1
Werner D.H. Baldacci D. Werner P.L. 《Antennas and Propagation, IEEE Transactions on》2004,52(2):380-387
The self-similar geometrical properties of fractal arrays are exploited in this paper to develop fast recursive algorithms for efficient evaluation of the associated impedance matrices as well as driving point impedances. The methodology is demonstrated by considering two types of uniformly excited fractal arrays consisting of side-by-side half-wave dipole antenna elements. These examples include a triadic Cantor linear fractal array and a Sierpinski carpet planar fractal array. This class of self-similar antenna arrays become significantly large at higher order stages of growth and utilization of fractal analysis allows the impedance matrix, and hence the driving point impedances, to be obtained much more efficiently than would be possible using conventional analysis techniques. 相似文献
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Zhong Yin Xiao Zi Hua Wang 《Journal of Infrared, Millimeter and Terahertz Waves》2004,25(9):1315-1323
In this paper, we present a new photonic crystal structure, which is composed of fractal Cantor multilayer with a defect embedded in its middle. Optical transmission matrix method is used to calculating the transmittance and reflectance. Compared with general Cantor multilayer, we find the new structure has wider stopband and shows a super narrow band in the middle of wider stopband. It can be served as a super narrow bandpass filter. The pass band obtained can be less than 0.6nm near the infrared 1530 nm. The optical transmission is the center wavelength is higher than 99 %. This means a very low insert loss. It is more superior to other kind narrow band filters. This kind of photonic crystal super narrow band optical filter may find applications in super dense wavelength division multiplexing for optical communications and precise optical measurement. 相似文献
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Chiraz Taha Taoufik Ammar Henri 《AEUE-International Journal of Electronics and Communications》2009,63(9):720-727
The analysis of fractal structures by conventional methods gets harder and harder when the number of length scales rises. In this study, we try to combine the renormalization method and the surface impedance model to help rigorous studying of electromagnetic diffraction of fractal structures at their final (infinitum) iteration. As an application, we applied the method to a couple of fractal structures: Cantor Iris 1D and 2D. 相似文献