共查询到19条相似文献,搜索用时 125 毫秒
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在射电望远镜和卫星通信天线中,圆极化器是关键部件之一。传统圆极化器在保证0.75 dB轴比时的相对带宽最多为41%,无法满足日益增长的宽频带应用需求。该文利用四脊波导的宽带特性,通过采用具有不同尺寸的水平脊和垂直脊,使四脊波导两个正交主模的相位常数不同,来实现宽带移相特性,并给出了一种宽带四脊波导圆极化器的设计方法。按照这一方法,设计了一款宽带C波段圆极化器,工作带宽为3.625~7.025 GHz,相对带宽64%。该文还研究了圆极化器主要参数变化对其性能的影响,加工并实测了一个圆极化器样机。实测结果显示出,该圆极化器两个正交极化的反射损耗均小于–21 dB,相差90°±3.8°,相应的轴比小于0.6 dB。测试与仿真结果吻合良好,证明了分析与设计方法的正确性。
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波纹方波导圆极化器是常用的圆极化器,波纹方波导移相器是它的关键组成部分.文中以路的方法对波纹方波导移相器进行了分析,计算了周期长度内相移量的宽频带特性和波纹方波导各个尺寸对驻波比的影响.应用电磁仿真软件对8 GHz~18 GHz波纹方波导移相器进行了优化,最后在整个频带内得到的相移量为90°±12°,驻波比小于1.1.加工后与其他零件装配成圆极化器,经过测试,在整个频带内轴比小于3 dB. 相似文献
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文中提出一种基于能量传输理论的非谐振波导缝隙阵列设计方法,设计了一款右旋圆极化非谐振波导缝隙阵列天线.圆极化由加载在波导缝隙上的切角正方形波导圆极化腔实现,文中分析了腔体的各设计参数对圆极化特性的影响,实现了圆极化腔与波导缝隙的分离设计.设计的8×8阵列天线工作在17 GHz,主频处能量辐射效率大于94%,主瓣增益25... 相似文献
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设计了一种新型脊波导缝隙圆极化天线。在脊波导宽边开并联纵缝,从波导耦合电磁波至其上方的四脊波导圆极化器,实现圆极化辐射。采用脊波导不仅减小了单元尺寸,更改善了天线的带宽性能。重点研究了四脊波导圆极化器对相互垂直的两辐射场分量的影响,优化单元的轴比特性。在提取单元谐振电导的基础上,设计了工作在10GHz 的1×10 圆极化波导缝隙阵列。对天线实物测试得到中心频率处的增益为16.8dB,第一副瓣电平为
25dB,阻抗带宽约为8.5%,相对轴比带宽(AR臆3dB)约为3.2%。 相似文献
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指出了波导结构及微带形式的TE21模圆极化合成网络的不足,介绍了3 dB分支定向耦舍器的基本原理,设计了新型C频段空气带状线形式的圆极化合成网络,并对该结构进行仿真和测试,结果满足性能要求.此种合成网络可与耦合器设计为一体,既可以增加结构强度,还缩短了传输路径,降低了损耗,目前已经成功应用在多种型号天线系统上. 相似文献
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8-18 GHz介质板极化器的分析与设计 总被引:2,自引:2,他引:0
介质板极化器在天线设计中的应用非常广泛。从介质板波导形成圆极化波的原理出发,推导出差相移与波导传播常数的关系式。因此只需利用数值方法计算波导的传播常数,从而减小了仿真计算量。分析表明在818GHz超宽带范围内,方波导中插入介质板的圆极化轴比理论上只能达到2.03dB。文中提出介质板插入结合波导口径变形的方法使圆极化轴比小于1.53dB,驻波比小于1.23。对介质板波导的关键参数进行误差分析,得到加工误差对圆极化性能的影响小于2.5%。 相似文献
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提出了一种高效率的模式变换器,将矩形波导的TE10 模式转换为圆波导的TE11 圆极化模式,并采用盒形窗真空封接。使用三维仿真软件进行模拟设计和优化,模拟结果显示,在中心频率35 GHz,驻波比为1.17,在34-36GHz 频率范围内,模式转换效率在83%以上。这种模式转换器可以用在回旋行波管输入耦合器上,结构紧凑、简单,易于加工。 相似文献
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Xin-Jian Niu Li-Xuan Wang Ying-Hui Liu Xian-Neng Zhu Xin-Hua Yu 《Journal of Infrared, Millimeter and Terahertz Waves》2014,35(9):732-742
Based on the mode coupling theory, a TE01—TM11 mode converter was designed and optimal results were obtained. In this paper, bandwidth of mode converter with axis exponential structure is the largest, and mode converter with axis sinusoidal structure is the most compact in the case of the center frequency is 28GHz and the waveguide radius is 16mm. If the bending angle between input port and output port of mode converter was demanded for 90°, mode converter with axis parabola structure had the characteristics of compact structure, higher mode purity and larger relative bandwidth. Meanwhile, we found that the converter could be also used as TE11 mode transition with transmission efficiency above 99%. But due to bending angle of this structure was restricted, its center frequency and waveguide radius had the obvious corresponding relation. 相似文献
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A waveguide polarization controller 总被引:1,自引:0,他引:1
In this paper a novel waveguide polarizer is introduced that does not require rotary joints and the frequency of operation can easily be adjusted by a few set screws. In this method the degenerate eigenvalues of a circular waveguide are separated by deforming the waveguide cross section slightly. In order to generate a desired polarization, the orientation angle of the deformation point with respect to the polarization of the incident wave can be adjusted using a rotary roller mechanism concentric with the circular waveguide. Analysis of the problem based on the finite element method and an approximate analytical method is given. A prototype model at 34.5 GHz is built and tested. Experimental results shows excellent agreement with the theoretical prediction 相似文献
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van der Tol J.J.G.M. Pedersen J.W. Metaal E.G. Oei Y.S. van Brug H. Moerman I. 《Photonics Technology Letters, IEEE》1993,5(12):1412-1414
A new type of mode-evolution polarization-splitter based on InGaAsP/lnP has been designed and realized. The component uses the large waveguide birefringence of the first-order TE and TM modes in a ridge waveguide made in a heterostructure, In the input section an asymmetric Y-junction acts as a mode converter in order to inject first-order TE- and TM-modes in a polarization-splitting section, which consists of a Y-junction formed by a bimodal and a monomodal waveguide. In the output section a third Y-junction is connected to the bimodal waveguide to couple the first-order mode to a monomodal output waveguide. Components that are 6-mm long and show polarization splitting at a wavelength of 1.55 μm have been realized. The best splitting ratios are close to -20 dB, which is in agreement with BPM simulations. Excess losses are below 1 dB 相似文献
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准光辐射器是高功率回旋管准光模式变换器的重要组成部分.本文首先采用几何光学理论分析圆波导准光辐射器,然后根据高斯波束(TEM00模)在辐射器切口处形成的原因,采用耦合波理论设计波纹波导准光辐射器.通过编写程序并进行数值优化完成140GHz,TE28,8模式回旋管波纹波导准光辐射器的设计,结果表明波纹波导辐射器的总长度仅为205.2mm,切口长度为47.2mm,在辐射器螺旋切口Brillouin区内高斯模式标量相关系数大于98%.本文所用的方法也可用于其它频率和模式的回旋管准光辐射器设计. 相似文献
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波导偏振器是片上集成相干光学系统中的关键器件之一,超高消光比、低损耗、紧凑型波导偏振器的设计一直是研究的热点。基于绝缘体上硅平台的倾斜Bragg光栅被用于实现超高消光比波导偏振器结构。利用一维光子晶体能带理论分别计算TE和TM模式光的能带结构分布,选择TE模式禁带与TM导带重叠带隙设计光栅,可实现TM模式低损传输,而TE模式被Bragg光栅高效反射,从而产生超高偏振消光比。3D FDTD仿真表明:16 μm倾斜Bragg光栅波导偏振器可在中心波长1550 nm附近70 nm的带宽内,实现大于37 dB的超高消光比,器件的损耗小于0.64 dB;进一步增加光栅周期数,当长度为25 μm时,消光比可提高至46 dB。Bragg光栅倾斜角与刻蚀宽度偏差仿真表明:设计的结构加工误差容限较大,同时该结构仅需一次曝光刻蚀,工艺流程简单。 相似文献
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Ching-Fang Yu Tsun-Hsu Chang 《Microwave Theory and Techniques》2005,53(12):3794-3798
This study presents the design and cold testing of a Ka-band TE/sub 01/-mode converter. A wave is efficiently converted from the TE/sub 10/ rectangular waveguide mode into the TE/sub 01/ circular waveguide mode. This converter comprises a power-dividing section and a mode-converting section. The field pattern and the working principle of each section are analyzed and discussed. A prototype was built and tested. Back-to-back transmission measurements exhibit excellent agreement to the results of computer simulations. The measured optimum transmissions are 97% with a 1-dB bandwidth of 5.8 GHz centered at 34.0 GHz. The angle-independent transmissions manifest high mode purity and the field pattern is directly demonstrated on a temperature-sensitive liquid-crystal sheet. In addition to exhibiting a high conversion efficiency, high mode purity, and broad bandwidth, this converter is also easy to construct and is structurally simple. 相似文献
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This work reports on measurements and calculations (coupled mode equations) on the conversion of transverse magnetic TM01 vircator mode at 4 GHz to the linearly polarized TE11 mode by means of mode converter systems using a circular waveguide with curvature. The mode converter is composed of a 38.78° bend with 39.07 cm curvature and a 50.78° inverse bend with 25.24 cm curvature in 9 cm internal diameter (ID) circular waveguide. The efficiency of conversion from TM01 to TE11 at 4 GHz exceeds 99%, and the overall efficiency from TM01 to TE11 exceeds 90% over a calculated range of 3.72–4.8 GHz. 相似文献
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圆波导TE01-TE11模式转换器设计与实现 总被引:1,自引:1,他引:1
基于耦合波理论的基础上,分析了TE01-TE11模式转换器的特性和半径渐变指数,讨论了中心轴线弯曲下的圆波导模式转换器,对中心频率33GHz的波导进行了模拟设计、仿真,在保证带宽的前提下,尽力降低转换器的长度和提高转换效率,最后达到了97.82%的转换效率,带宽达到2GHz。 相似文献