相控阵雷达中宽带波导和差网络的研究

介绍了一种由4个宽带波导魔T级联而成的X波段宽带和差网络.采用一种改善宽带波导魔T频率特性的新颖方法,在波导魔T的E面上级联变换段和H臂上增加电感膜片,得到40%带宽内优异电性能.并通过理论分析、三维电磁仿真构造了具有同样优异性能的宽带波导和差网络.最后,给出了波导魔T和波导和差网络的实测结果.     

宽带波导魔T的设计

介绍了一种宽带波导魔T的设计，并使用三维电磁仿真软件对其进行仿真计算。本设计中波导魔T的带宽达到了一个倍频以上，使其有了更广的使用范围。     

宽带脊波导魔T的设计

介绍了一种宽带脊波导魔T,该模型通过两根金属棒将魔T的H臂的上脊与E臂的双脊相连,采用阻抗变换的思想,通过切比雪夫阶梯阻抗枝节变换实现高低阻抗之间的过渡,并在ET接头和HT接头的交界处添加金属匹配块来改进接头的过渡匹配。文中分析了宽带脊波导魔T的设计原理,采用WRD650 脊波导设计,利用全三维仿真软件进行了仿真验证,在10 GHz ~18 GHz的频率范围内得到较好的性能指标。     

一种应用于电子战的双脊波导魔T接头

提出了一种可以应用于电子战的双脊波导魔 T 接头,介绍了它的基本原理,运用模式匹配和迭加的方法,对双脊波导魔 T 接头进行了分析和计算,设计了一种新型的双脊波导魔 T 接头.它不仅工作频带比标准波导魔 T 宽很多,而且结构尺寸大大减小,实现了宽频带功率分配器、合成器和射频电子开关的功能.实物测试的结果表明其性能良好.     

L波段波导高方向性取样装置

微波矢量网络分析仪,标量网络分析仪和扫频测试仪,在构成高性能波导宽带扫频测量系统时,都需要波导宽带高方面性取样装置。在厘米波到毫米波的高频波段,它是由波导宽带高方向性耦合器来实现的。在分米波段,由于波长长,≤≤波导尺寸大,波导宽带高方向性耦合器的长度可长到数米,实际使用极不方便,一种基于宽带波导魔T电桥L波段的波导微波测量高方向性取样装置在西安恒达微波技术开发公司研制成功,从而解决了大尺寸波导宽带高性能测量的问题。     

一种新型复合结构的四分之一波长带通滤波器

提出了一种基于共面波导(Coplanar Waveguide,CPW)和微带线复合结构的四分之一波长带通滤波器(Bandpass Filter,BPF)。该带通滤波器由两个终端开路的T形微带馈线结构和四个交叉耦合的四分之一波长CPW谐振器组成。通过仿真优化得到其特性曲线图,并分析比较了不同参数对其滤波性能的影响。仿真结果表明,该带通滤波器在其2.97～3.03 GHz的通带内的最小插损低于0.4dB,回波损耗大于30dB,同时其带外衰减都大于25dB。这种滤波器结构紧凑,尺寸小,性能好,可应用于很多微波系统中。     

Ka波段单脉冲和差网络设计

和差网络是毫米波单脉冲雷达前端中的一个重要器件,设计了一种由四个阶梯型波导魔T组成的Ka波段和差网络。相比于传统的波导匹配魔T,该新型魔T由于采用了阶梯型过渡匹配结构,抗振动能力较好。四个魔T按一定方式排列和连接,以使和差端口成一直线分布,四个接收端口成"十"字型分布,易于系统集成。通过三维电磁仿真软件优化设计,在34 GHz~36 GHz范围内,和差器各端口回波损耗大于15 d B,当和端口激励时各输出端口的幅度一致性小于0.1d B、相位一致性小于5°。最后,给出和差网络的实物测试结果,并与仿真结果对比。     

8mm波导魔T的仿真分析

介绍了一种8 mm波导魔T的设计,采用仅在魔T接头处加入匹配元件,设计出了一种结构简单的魔T结构形式,并使用三维仿真软件对其进行仿真计算。仿真结果表明:在32.5~37.5 GHz范围内实现了功率等分,端口间的隔离度优于-30 dB,回波损耗小于-20 dB,等分臂功率差值小于0.1 dB,工作带宽大于14%。     

π／2极化变换器的设计

极化变换器作为一种微波器件常用在卫星通信、雷达等领域，其主要用来实现线极化波和圆极化波之间的变换，合理、精确的设计能得到良好的电气参数。本文把圆波导内部部分填充的介质片等效为在两个正交面内均匀填充的介质，在理论上进行了分析，给出了设计公式，并在C波段设计计算了极化变换器的参数。将给定的电气尺寸在Ansoft软件上进行了模拟分析计算，从结果可以看出，设计方法是正确的。     

利用偏移半销钉结构设计带阻滤波器

介绍了一种新颖的波导类椭圆带阻滤波器.该滤波器的结构由传输TE10主模的矩形波导中的偏移半销钉和四分之一波长传输线组成.波导中半销钉的等效电路即在谐振频率处为一个串联LC谐振电路,此谐振电路产生一个衰减极点.销钉的高度主要用来控制谐振频率,销钉距离波导中心的偏移量用来控制谐振单元间的耦合强度.最后设计了一个中心频率为9...     

A Compact Monopulse Radial Line Slot Array Antenna at Millimeter Wavelengths

This paper describes the design and performance of a radial line slot array antenna (RLSA) which generates sum or difference far field patterns. The antenna consists of rectangular waveguide to radial line transition, radial line and slot arrays etched on the upper plate of the radial line. A novel rectangular waveguide to radial line transition is designed to build up the dominate TEM mode in radial line to excite the slot arrays which are arranged in concentric rings on the upper plate of the radial line. The antenna radiates linear polarization at Ka band. Monopulse operation is obtained by a sum and difference network which is a compact eight-port comparator consisting of coplanar magic tees. The sum and difference network is waveguide structure whose loss is less than that of microstrip structure at millimeter wave lengths. The monopulse performances can be used in monopulse tracking and anti-collision application etc. Genetic algorithm (GA) is applied to optimize the parameters of the transition and antenna to obtain good performances.     

A Five-Port Matched Pseudo-Magic Tee

The five-port matched pseudo-magic tee consists of an input waveguide, two load arm waveguides which are coupled into the input waveguide with +90° and -90° phase shifts, respectively, and an output waveguide which is split into two load waveguides by a septum. The improvements include a much broader matching and isolation bandwidth, higher isolation between arms, better matching into arms, and a variety of modifications for different applications. These characteristics have been obtained by employing frequency-insensitive phase shifters. Hence, frequency coverage is mainly limited by mechanical asymmetry and the characteristics of the directional coupler in the magic tee. While this type of hybrid junction is not a true magic tee because the load arms are not used as the input arm, it does have several applications which an ordinary magic tee does not have. X-, K-, and M-band models were examined experimentally, and highly sensitive and accurate impedance measurements were made.     

The design of a mode selective directional coupler for a high power gyroklystron†

The design method of mode selective directional couplers from a transverse electric mode in a circular waveguide to the fundamental mode in a rectangular wave guide is presented in this paper. The design results for a TE₀₁ circular mode coupler intended for use in the output power measurement of a high power gyroklystron are reported; these results indicate that more than 50-80dB directivity and sufficient suppression of unwanted modes can be obtained with a coupler less than 07m in length. The effects of frequency and rectangular wave guide size on coupler parameters are also discussed in this paper     

Silicon Micromachined W-Band Hybrid Coupler and Power Divider Using DRIE Technique

In this letter, a silicon micromachined W-band hybrid coupler and a power divider using deep-reactive ion etching (DRIE) technique are presented. They are designed in the H-plane of rectangular waveguide to utilize DRIE technique. The hybrid coupler adopts a ridged waveguide 90deg phase shifter and a joint waveguide. The power divider utilizes a T-shape configuration. The simulated and measured response of each circuit are presented in this letter where good agreement between them is achieved. Then, the measured combining efficiency is reported by cascading the power divider and the hybrid coupler.     

W波段双极化单脉冲天线设计

为了探测目标的极化特性,研制了工作在W波段的双极化单脉冲卡塞格伦天线.天线由主反射面、副反射面、馈源喇叭、正交模耦合器及和差器组成.天线主反射面口径为137 mm,馈源为五喇叭形式,正交模耦合器采用渐变波导匹配方案,和差器通过平面型定向耦合结构实现.通过将馈源喇叭、正交模耦合器及和差器集成设计,减小了连接损耗,压缩了天线纵向尺寸.测试结果表明,天线驻波带宽约3. 7 GHz,极化隔离度优于35 dB,和波束增益大于37. 9 dBi,副瓣电平优于-15 dB,差波束零深优于-25 dB.天线在W波段实现了较好地双极化单脉冲性能.     

Circular Electric Mode Directional Coupler

This paper describes a circular electric mode directional coupler, composed of two coaxial bifurcations in circular waveguide. The coupling coefficient of the directional coupler depends on the separation between the two bifurcations, and a hybrid junction for the circular electric mode may be obtained at the proper separation. The analysis is carried out in terms of scattering matrix elements characterizing each coaxial bifurcation. The scattering matrix elements were experimentally determined via the Weissfloch tangent method at 5000-Mc band. For convenience, experiments were carried out in sectoral waveguide instead of circular waveguide. Measured characteristics at 9000-Mc band are in good agreement with values determined by circuit calculations employing parameters of the coaxial bifurcation measured at 5000-Mc band. For the case of a hybrid junction, wide-band matching has been accomplished and verified experimentally. Applications of this directional coupler are outlined.     

（英）高效锥形太赫兹耦合器

设计了将太赫兹波耦合进入波导的耦合器.耦合器由金属材料铝制成,形状为中空圆锥形和圆柱形的结合.在宽带的脉冲太赫兹信号和单频的连续太赫兹信号两种情况下,模拟并实验测试了耦合器将自由空间传输的平行太赫兹波耦合进入反谐振波导,结果显示该耦合器是宽带太赫兹波耦合器.通过优化耦合器几何参数,在太赫兹时域系统下得到振幅耦合率达到71%,振幅增强因子为6.125.     

Analysis of a centered-inclined waveguide slot coupler

Integral equations are developed for a centered-inclined coupling slot (including the effect of finite wall-thickness of the common broad-wall) and the slot-aperture electric intensity field is found using the method of moments. Numerical results for resonant length, backscattered wave amplitude, and phase variation off-resonance are presented over a range of values of the waveguide b dimension, wall thickness, slot width, and frequency. It is shown that the resonant length is relatively insensitive to slot tilt, &thetas;, for a standard-height X-band waveguide, whereas its dependence on &thetas; is significant for reduced-height waveguides. The phase variation of scattered TE₁₀ waves in both waveguides off-resonance is less for wider slots and smaller b dimensions. Shunt-series coupling slots exhibit greater phase variation off resonance when compared to a centred-inclined coupling slot. Also, the former has a longer resonant length for a smaller b dimension and for a wider slot. Thus the centred-inclined slot coupler possesses superior characteristics. The higher-order mode coupling between a centred-inclined slot coupler and a pair of straddling radiating slots in the branch waveguide is significant     

A novel quasi-optical monopulse-tracking system for millimeter-waveapplication

A novel, low-loss, polarization-independent quasi-optical monopulse comparator (QOMC) has been developed as an alternative to the commonly used waveguide comparator. It has been implemented as an experimental model with an aperture of 23×23 wavelengths for a 140-GHz monopulse tracking antenna fed by a beam waveguide. The QOMC consists of two cascaded identical stages (sections) to perform azimuth and elevation angle measurements. Each comparator stage is composed of only two plane-parallel reflectors and a low-loss quasi-optical 3-dB beam splitter symmetrically positioned in between them. Extensive model calculations of a single QOMC stage with square aperture dimensions between 10 and 25 wavelengths, and experimental investigations of the realized two-stage QOMC in a beam-waveguide field were performed. Owing to its sufficient high dynamic range at bandwidths of up to about 300 MHz, and particularly, its low absorptive loss of less than 3.5% per stage at 140 GHz, this QOMC is suited ideally for millimeter-wave applications