无线电设备、电信设备

TN811,TN8142005040705一种新型同轴TEM-圆波导TE11模式变换器/刘庆想,袁成卫(西南交通大学理学院)//强激光与粒子束.―2004,16(11).―1421～1424.提出了一种新型同轴插板式模式变换器,可以实现同轴TEM到圆波导TE11模式的变换。介绍了这种模式变换器的工作原理:即通过在同轴波导中沿轴向插入金属板,将同轴TEM模变换成扇形截面波导TE11模,进而利用不同扇形截面波导中的相移改变电场分布的轴对称性,在同轴波导中形成同轴TE11模,最后将同轴TE11模转换为圆波导TE11模式。基于这一原理设计了一个中心频率为3.8GHz的同轴TEM-圆波导TE…     

矩形波导到高功率过模圆波导模式转换器的设计

矩形波导到高功率过模圆波导模式转换器是高功率微波测试系统中的关键组件.针对这一问题,本文首先建立了模式转换器的N端口波导结全波分析模型,然后计算了模式转换器的反射系数.给出一种优化设计方法.最后,优化设计了一个X波段的矩形波导到高功率过模圆波导模式转换器,其结构紧凑,反射系数小且电场极化为垂直方向.测量结果与仿真结果吻合良好,证明了设计方法的可行性.     

一种新型圆极化高功率微波天线

介绍了一种新型圆极化高功率微波天线,可辐射高功率微波源所产生的 TEM 或 TM_(01)模。该天线由同轴插板式模式转换器和一种新型同轴插板式喇叭组成,模式转换器将输入的同轴 TEM 模转换为4个相位依次相差90°的扇形波导 TE_(11)模,并通过新型喇叭辐射,在轴向上获得了圆极化辐射场。优化设计了一个中心频率为4GHz 的天线,其总长度为385mm,喇叭口径320mm。在中心频率上天线增益为19.3dBi,轴比1.06,反射损耗-20dB。在 3.8～4.2GHz 的频率范围内增益大于18.9dBi,反射损耗小于-10dB。     

基于波纹喇叭天线的模式转换器

为提高高功率传输系统的模式转换效率,利用波纹喇叭的设计方法研究了TE11模至HE11模的转换器。设计了基于正弦－平行剖面以及tanh剖面的2种不同结构的模式转换器,并利用商业软件进行仿真验证。仿真结果表明,在94 GHz附近10 GHz的带宽范围内,高斯度可以达到98.6%以上,中心频点的高斯度达到99.2%以上。设计的2种结构中,正弦—平行剖面具有输出束腰半径处于开口处的优点,而tanh剖面具备尺寸小、相位中心固定的优点。     

TE01弯头切比雪夫设计方法

TE01弯头在高功率微波系统装配中有着重要作用。随着高功率微波朝着高功率、大带宽方向发展,对TE01弯头提出了高功率容量、更大工作带宽的需求。传统设计方法往往存在带宽较窄,功率容量受限的问题。TE01弯头设计难点在于存在TM11简并模。本文在椭圆波导解简并的基础上,提出了TE01弯头切比雪夫设计方法。采用耦合波理论分析完成了弯头设计过程。仿真设计了Ka频段椭圆弯头结构,长半轴为7 mm,短半轴为5.25 mm。计算机仿真结果表明：模式保留效率95%以上的频率范围从32 GHz到45.1 GHz,验证了设计方法的有效性。     

模式抑制器在Ku波段在线测量系统中的应用

在Ku波段低磁场相对论返波管中,由于阴极发射的角向不均匀性,产生的微波除了TM01模,还有主模TE11等其他微波模式。由于目前设计的圆波导耦合器只能测量TM01模式功率,其他微波模式存在会导致在线微波波形异常,给在线测量带来困难。本文设计了一种模式抑制器,其结构由5个腔组成。通过数值模拟和实测结果得出：TM01模在频率14.8~15 GHz衰减小于0.1 dB,而对其他模式,如主模TE11模式微波能够全反射。模式抑制器置于相对论返波振荡器(RBWO)与圆波导耦合器之间,实验观察在线输出微波与辐射场波形一致,微波功率符合较好。     

新型高功率微波模式转换天线研究

给出了一种新型高功率微波模式转换天线,该天线将同轴插板式模式转换器和一种新型喇叭有机结合,可直接辐射高功率微波源输出的同轴TEM模或TM01模,具有结构尺寸小、口径效率高、轴向辐射、容易实现等优点.优化设计了一个中心频率为3.8GHz的天线,长度约300mm、口径为280mm,在中心频率上增益为19dBi、反射损耗为-20dB,在3.7～ 4.1GHz的频率范围内增益大于18.7dBi、反射损耗小于-15dB.     

基于斜极化法的电光聚合物光波导偏振转换器

采用斜极化法研制了电光聚合物光波导偏振转换器,分析并设计了器件的45°斜角电极化结构,并基于DR1/PMMA电光聚合物材料,对器件进行了制作.所研制的偏振转换器,由TE模到TM模和由TM模到TE模的偏振模转换效率分别约为93.6%和95.1%,偏振转换周期电压约为380V.并讨论了器件性能进一步提高的可能性与方法.     

螺旋波纹波导在高功率微波领域中的应用研究

螺旋波纹波导是一种具有特殊结构的高功率微波源波导结构,螺旋波纹波导的特殊结构使得TE11和TE21两模式在角向耦合,耦合出的新工作模式具有良好的色散特性和模式选择特性,因此该波导具有广泛的应用价值。简要地介绍了螺旋波纹波导的结构原理,概述了该波导在高功率微波领域的工作原理。通过分析和模拟计算表明,螺旋波纹波导在高功率微波源中极具发展潜力,值得进一步研究。     

一种X波段GW级TE21模耦合器的设计

针对目前高功率微波(HPM)传输与发射系统无法实现自跟踪的问题,引入TE21模耦合器,使HPM系统具备自跟踪能力。由于现有的TE21模耦合器应用到HPM中会面临功率容量的问题,为此设计一种X波段GW级TE21模耦合器,以探索其在HPM系统中的应用。仿真结果表明：设计的TE21模耦合器在9.0~10.0 GHz频率范围内,对TE21模的耦合度大于-0.5 dB,对TE11模的耦合度小于-40 dB,功率容量可达到GW量级。     

The coaxial beam-rotating antenna (COBRA): theory of operation andmeasured performance

Many microwave generators, especially high-power sources, utilize an azimuthally symmetric output mode such as the TM₀₁ circular waveguide or the coaxial TEM mode. If such a mode is projected into an antenna aperture and radiated directly, then a doughnut-shaped radiation pattern with a boresight null will result. Antenna designs to directly accommodate an azimuthally symmetric output mode and the high electric fields of high-power sources have been considered, but they tend to be low gain, do not radiate a boresight peak along the axis of the source, and the pattern peak direction changes with frequency. Mode conversion techniques to alter the aperture field distribution have also been explored, but losses and weight, size and cost additions impact negatively on total system design. This paper describes a novel antenna we call the coaxial beam-rotating antenna (COBRA) that mitigates many of the problems normally associated with the azimuthally symmetric output modes of high-power microwave sources. The COBRA accepts directly an azimuthally symmetric guided mode of a microwave source and radiates a high-gain pattern with a boresight peak. In addition, the COBRA operates with a wide bandwidth, is compatible with the intense electric fields associated with high-power microwave sources, and the geometry of the antenna can be easily configured to produce an arbitrarily (elliptically) polarized boresight field. This paper presents the fundamental theory of operation, derives pertinent design and performance equations, and gives the measured operating characteristics of a COBRA prototype     

A novel TEM-TE/sub 11/ mode converter

A novel mode converter that transforms coaxial transverse electromagnetic (TEM) mode to TE/sub 11/ circular waveguide mode is investigated. It is shown that with four metal plates inserted in the coaxial waveguide, the TEM mode will be converted to coaxial TE/sub 11/ mode, and finally, it forms a TE/sub 11/ conventional circular waveguide mode. The experimental test results are in good agreement with the computer simulations, which demonstrates the feasibility of the mode converter.     

Q波段圆波导轴线弯曲TE01-TE11模式变换器设计

在模式耦合理论的基础上, 采用相位重匹配技术对圆波导轴线弯曲TE01-TE11模式变换器进行了数值优化计算和分析.在Q波段给出了两种不同周期数TE01-TE11模式变换器的优化设计参数.数值计算表明: 四周期模式变换器的最高转换效率为98.82%, 带宽为2.2 GHz, 六周期最高转换效率为99.89%, 带宽为1.7 GHz.研究了模式变换器关键几何尺寸在小范围内变化对转换效率的影响.并利用HFSS对给出的模式变换器进行了仿真, 仿真结果与数值模拟一致性较好.同时加工了六周期结构模式变换器并进行了小功率热测实验, 测试结果表明输出了模式纯度较高的TE11模式.     

Simulation of polarization converter formed by poling-inducedpolymer waveguides

A polarization converter using electrooptic (EO) polymer waveguides is proposed and it is simulated by a full vectorial beam propagation method (VBPM) for anisotropic medium. First, an efficient structure of poling electrodes is proposed for the fabrication of TE-mode poling-induced waveguides in EO polymer. For given electrode structures of both TE-mode and TM-mode waveguides, poling-induced dielectric tensors are calculated by the finite-element method to provide refractive index distribution, data for VBPM simulation. It is shown numerically that the poled TE and TM mode waveguides work efficiently as the corresponding polarization filters. Then, new poling electrodes are suggested to fabricate a waveguide device formed by connecting the TE and TM mode waveguides adiabatically with a slowly varying structure. This waveguide device has the optic axis slowly rotating as one moves along the propagation direction, so that it will act as polarization converter. VBPM simulation shows that the polarization of the guided mode rotates following the optic axis distribution. Polarization conversion is demonstrated successfully with high conversion efficiency and low excess loss     

基于太赫兹超材料的微流体折射率传感器

设计加工了一种太赫兹超材料微流体传感器件,利用时域有限差分法（Finite Difference Time Domain,FDTD）对其在太赫兹波段的传输、谐振及传感特性进行数值模拟。采用太赫兹时域光谱系统实验研究了偏振方向对传感器灵敏度的影响。实验结果表明,当超材料谐振环开口方向与入射太赫兹波的偏振方向平行和垂直时,折射率传感灵敏度可分别达到39.29 GHz/RIU和74.43 GHz/RIU。通过等效电路模型对该超材料器件的传输和谐振特性做了分析,并进一步明确了其传感机制。该超材料器件可对微量液体（5 l/mm2）实现芯片式的折射率传感,具有较高的传感灵敏度,在化学生物传感器的设计和制造领域具有潜在的应用前景。     

Analysis and Design of TE/sub 11/-to-HE/sub 11/ Corrugated Cylindrical Waveguide Mode Converters

A theoretical parametric study is given of a TE/sub 11/-to-HE/sub 11/ mode converter consisting of a section of cylindrical corrugated waveguide with varying slot depth. The analysis makes use of modal field-matching techniques to determine the scatter marks of the mode converter from which we deduce its propagation properties. It is shown that a mode converter consisting of only five slots achieves a return loss better than 30dB over the band 2.7相似文献   

圆波导TE01-TE11模式转换器设计与实现

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。     

X-band TM/sub 01/-TE/sub 11/ mode converter with short length for high power

A mode converter for X-band located between a generator and an antenna to convert TM/sub 01/ to TE/sub 11/ mode with high efficiency for a high power transmitting system is presented. The proposed mode converter has extended radius and excessive curvature with symmetric structure in order to convert between two modes efficiently with short length. The measured and simulated results of the return loss, mode patterns and efficiency of the proposed mode converter with 200 mm length are provided.     

高功率微波混合模式辐射特性的初步研究

通过阐述模式识别的重要性及其在高功率微波中的特殊性，论证了利用辐射特性来识别模式的可行性，并以某金属截面圆波导为例，通过纯解析、半解析、数值模拟三种方法对其中的TE11和TM01混合模式辐射场分别进行计算和分析，得到基本物理图像和特征，实验结果为模式判别提供了初步判据。     

Cylindrical Dielectric Resonators and Their Applications in TEM Line Microwave Circuits

A cylindrical sample of low-loss high epsilon/sub r/ placed between two parallel conducting plates perpendicular to the sample axis forms a microwave resonator. A simple approximate method for predicting the resonant frequencies of the TE modes of this structure is developed. The method becomes exact for the fitting case of this structure which is known as a dielectric post resonator. In all cases, the accuracy of the method is shown to be better than 3.5 percent. The TE/sub 01delta/ mode chart presented allows the determination of the resonant frequency and the tuning range of any cylindrical dielectric resonator for which epsilon/sub r/ >or= 10. The properties of the dielectric resonator as a TEM line element are demonstrated experimentally.