一种宽带四脊波导正交模极化耦合器

坐落于贵州天然喀斯特地形的500 米口径球面射电望远镜(FAST),其低噪声接收机系统需要高性能正交模极化耦合器,对此,提出了一种四脊波导形式宽带正交模极化耦合器快速有效的设计方法:首先分别设计四脊波导正交模极化耦合器的两个关键部分,然后进行整体优化,为了改善带内阻抗匹配性能可以在同轴输出端口的内探针引入阶梯匹配环。使用这种方法研制的FAST L 波段极化器工作带宽达到2 颐1,在整个带宽范围内极化器的反射系数小于-20 dB,极化耦合水平低于-43 dB,带内插入损耗优于0. 15 dB,仿真和实测结果有很好的一致性。提出的设计方法适用于各种频率范围的宽带四脊波导正交模极化耦合器的设计。     

三端口T型接头建模研究及高性能分支线耦合器设计

本文提出一种基于导纳矩阵的三端口T型接头高精度超宽带等效电路参数提取方法.并将传统T型接头结构改进为凹-T型接头(concave)和凸-T型接头(convex)两种形式,以精确控制T型接头中心处寄生电容的影响.最后,在分析不同三端口T型接头连接方式对其等效电路及寄生电容影响的基础上,将改进后的T型接头结构用于研制一个中心频率12GHz高性能分支线耦合器.实测结果表明,在中心频率处该耦合器各端口的回波损耗和端口隔离度均小于-26dB,总插入损耗小于1.0dB,幅度差别小于0.1dB.     

X波段宽带正交双线极化天线设计

为了满足某型电子系统特定的性能要求,本文研制了工作频率覆盖X波段全频段的正交双线极化喇叭天线。正交双线极化特性的实现主要是基于对称五端口分支形式的宽带正交模耦合器,喇叭天线的开口结构尺寸保证了覆盖空域的增益要求。在理论分析与仿真设计的基础上,加工了该天线工程样机并进行了实验验证。实测结果与仿真结果非常吻合,表明在所要求的工作频段内天线电压驻波比小于1.8,正交极化端口隔离度优于50 dB,并且具有优良的辐射特性。     

一种双频段正交模耦合器的设计

对水平/垂直极化波模式进行分析,并基于分析设计了一种双频段正交模耦合器。对一个正交模耦合器来说,各个端口的端口匹配和隔离尤为重要,引入模式正交的极化隔离能增加隔离效果。改变金属膜片的尺寸与位置,能够使得正交模耦合器中端口R5.75所输入的水平极化波从端口WR42匹配输出,而不影响端口R5.75所输入的垂直极化波。增加圆波导至波导WR28之间的匹配段,能够匹配加入膜片之后正交模耦合器的垂直极化波的输出。基于上述分析,设计了一种双频段正交模耦合器。     

一种超宽带耦合带线3dB耦合器设计

本文介绍了一种超宽带耦合带线3dB耦合器的设计.通过10%的加工公差仿真设计表明该种耦合器具有优良的性能.实际的设计结果在1.2～4.2GHz频带内插入损耗小于0.5dB,带内波纹大于-0.25dB小于 0.35dB,端口隔离大于17dB,端口驻波小于1.3.文章还对该种耦合器的峰值功率容量进行了分析,为其高功率应用提供了依据.     

基于耦合带线超宽带耦合器的分析与设计

介绍了一种基于耦合带线超宽带耦合器的分析与设计。实际设计的超宽带3dB耦合器在1.2~4.2GHz相对带宽110%的频带内,插入损耗小于0.5dB,带内波纹大于-0.25dB小于 0.35dB,端口隔离大于17dB,端口驻波小于1.3。     

一种宽带正交模耦合器的设计

介绍了一种基于对称五端口分支形式的宽带正交模耦合器.对称五端口分支将方波导内的双极化波分离成为水平和垂直2个相互垂直的分量.其特点为:相对于公共波导对称放置的一对相同的波导双接头分配给每一主模,因此每个接头传输主模提供信号一半的能量,双接头的3 dB信号必须用附加的元件适当组合,以便在一个界面端口上提供给定极化总的信号能量.文中介绍的宽带正交模耦合器主要由对称五端口分支、功率合成器及相应的变换段组成.利用阻抗变换原理进行仿真计算,在理论分析的基础上进行了大量的实验研究.最后给出了正交模耦合器在X波段大于90%波导带宽工作的电性能测量结果.     

一种超宽带宽边耦合微带定向耦合器

提出了一种新颖的超宽带宽边耦合微带定向耦合器,相比窄边耦合结构,宽边耦合增加了耦合面积,可实现宽频的3 dB紧耦合.同时,为进一步拓展耦合器工作带宽,该文采用渐变耦合结构替代传统的矩形耦合结构.通过HFSS仿真验证,此定向耦合器在2～6 GHz频带内插入损耗小于0.9dB,输入端口回波损耗大于20 dB,端口隔离度大于21 dB.     

利用复合左右手传输线实现的两种平行耦合线定向耦合器

采用紧凑的复合左右手传输线模型实现了两种新型平行耦合线定向耦合器.第一种定向耦合器为六端口双定向耦合器,形式为右手传输线/复合左右手传输线/右手传输线,通过调整传输线与传输线之间的距离,实现一分三等分功率分配器的功能;第二种定向耦合器是在普通定向耦合器中,用部分复合左右手传输线代替右手传输线,通过调整它们之间的比例,可以使得耦合端和输出端的输出相位相等.设计的两种定向耦合器,均已通过实测验证.     

一种C波段宽带正交模耦合器设计

正交模耦合器是实现天馈系统双极化的关键部位，适用于雷达探测、电子对抗以及无线通讯系统等多个领域。本文设计了一款Boifot型的C波段宽带正交模耦合器，通过垂直极化通路和水平极化通路的独立仿真，阐述了正交模耦合器工作带宽的扩展方法和工作原理。结果表明，在其工作频段43%的相对带宽内，回波损耗小于-20 dB，传输损耗小于0.07 dB，端口隔离度优于-57 dB，交叉极化水平低于-60 dB，实现了宽带低损耗高隔离的良好性能。     

一种新型宽带双极化微带贴片天线的设计

摘要：运用口径耦合理论、腔模理论、反相馈电技术和多层贴片结构设计出一种新型的P波段（中心频率为0．75GHz）宽带双极化微带贴片天线。天线的两个极化端口采用共面馈电;馈电网络设计中采用短路耦合线实现反相馈电。仿真结果表明该天线两个极化端口实际增益均达到8．5dB,水平极化端口在0．64-0．85GHz频率范围内驻波比小于2,相对带宽为28％;垂直极化端口在0．68-0．85GHz频率范围内驻波比小于2,相对带宽为22．6％,两端口隔离度高于53dB。     

高隔离度双极化微带天线直线阵的设计

本文介绍一种新型的1×16双极化微带天线直线阵的设计.该天线采用双极化角馈方形贴片单元,阵列的垂直极化端口采用共面馈电,水平极化端口采用口径耦合,并在馈电网络中应用反相馈电技术.实验结果表明,天线二端口驻波比小于1.5的相对带宽分别达到15％和13.5％,两端口之间的隔离度在频带内高于33dB,最大达到43dB.本直线阵可用作星载综合口径雷达系统的天线子阵,便于与有源收发器件结合.     

一种P波段宽带双极化微带天线阵列

介绍了一种P波段宽带双极化微带天线单元及2元阵列的设计。天线单元设计中采用口径耦合理论和多层贴片结构,增大了天线的带宽,两个极化端口采用共面馈电;馈电网络设计中采用反相馈电技术有效抑制了交叉极化,采用短路耦合线实现反相馈电,降低了对天线带宽的影响。仿真结果表明,该天线阵实际增益达到11.8dB,水平极化端口在0.68～0.86GHz频率范围内驻波比小于2,相对带宽为24%;垂直极化端口在0.63～0.86GHz频率范围内驻波比小于2,相对带宽为30.6%,两端口隔离度高于40dB。     

A Broad-Band Dual-Mode Circular Waveguide Transducer

This paper describes a broad-band dual-mode waveguide transducer designed to couple two orthogonal TE/sub 11/ circular waveguide modes in separate rectangular waveguide ports. A compact, rugged, and economical junction has been developed to operate from 8600 mc to 9600 mc with a vswr of less than 1.15 at the rectangular port and a mode isolation of 50 db or greater. Developmental models are described to indicate the evolution from theory to the final model. Some problems encountered in attaining a small physical size are discussed in detail. The new junction has application to mode multiflexing, circular waveguide ferrite devices, circular polarization, and as a circular wave guide magic-T.     

Port reduction methods for scattering matrix measurement of ann-port network

The port reduction method (PRM) is a method to acquire the scattering matrix of an n-port network from the scattering matrix measured at a reduced port order by terminating certain ports. This then relaxes the instrumentation requirement and calibration procedure. As the port order is reduced to two, the scattering matrix of an n-port network can be obtained from the measurement using a conventional two-port vector network analyzer. In this paper, we describe two novel PRMs, which can reduce the order of measured ports to two. The experimental results show good accuracy. These two PRMs can provide a simpler calibration procedure and instrumentation than those directly using an n-port network analyzer. In addition, they give more accurate results than those measured by a two-port network analyzer with the assumption of using ideal terminators     

Research on dual-polarized circular waveguide antenna fed by L-shaped probes

This paper researched a kind of dual-polarized and cylindrical waveguide antenna fed by two L-shaped probes at the antenna bottom. The designed antenna was composed of two orthogonal L-shaped coaxial probes and a cylindrical waveguide cavity. The two orthogonal field structures were excited and the dual-polarized radiation mode was formed. The feeding cables of two polarization ports went through the bottom of the cylindrical cavity and were connected with the microwave adaptors. The bottom feeding structure was suitable to constitute a planar antenna array. The electromagnetic simulation and optimization design of the proposed antenna were carried out by using the full wave electromagnetic simulation technique, and the simulation results showed that the isolation between two polarization ports were more than 20 dB within the frequency range of 4.8–5.4 GHz. At the center frequency, the cross-polarization levels of radiation pattern were lower than −21 dB at the boresights and the beam width of radiation patterns at E-plane and H-plane were more than 70° for two polarization ports. The designed antenna in this paper was fabricated and measured. The measurement results indicated that the designed antenna achieved anticipated radiation performances and design effectiveness of the dual-polarized antenna in this paper was proved. The dual-polarized and cylindrical waveguide antenna is suitable for some application fields such as dual-polarized array radar. The research results in this paper can provide a technical basis for the practical engineering application.     

基于MSP430的串口扩展设计

工业控制领域,应用系统通常需要多个串口进行通信,但作为控制中枢的计算机往往只有一至两个串口,常常不能满足实际需要。设计了一种基于MSP430F149混合信号处理器和多路复用器ADG707的串口扩展系统,对主控机进行串口扩展,扩出4个分时使用的RS232口和2个RS422口与被测计算机通信,解决主控机串口不足的问题。系统客户端软件采用Microsoft Visual C＋＋6.0设计,在实际应用中,该串口扩展系统性能稳定可靠,满足方案要求,并且可以根据现场要求,增加或减少扩展串口的数量。     

Dual-Polarized Microstrip Patch Planar Array Antennas With Improved Port-to-Port Isolation

A method of preventing the degradation in the isolation between the orthogonal polarization ports caused by beamforming network routing in combined edge/aperture fed dual-polarized microstrip-patch planar array antennas is described. The simulated and measured performance of such planar arrays is demonstrated. Measured port isolations of 50 dB at center frequency, and more than 40 dB over a 4% bandwidth, are achieved. In addition, insight into the physical reasons for the improved port-to-port isolation levels, of the proposed element geometry and beamforming network layout, is obtained through prudent use of the electromagnetic modelling.      

双极化方向回溯整流天线阵列设计与实验

提出了由双极化方向回溯Van Atta天线阵和差分整流电路组成的方向回溯整流天线阵,它能够避免接收波束未对准和收发天线极化失配而造成整流天线转换效率的急剧下降,使整流天线在宽入射角和任意极化时仍能保持稳定的直流输出.设计并测试了C波段2×2元阵列.实验结果表明,当入射波功率密度为3.43 mW/cm2时,双极化方向回溯整流天线阵列的垂直和水平极化端口归一化电压比大于0.8的入射角度范围分别为[-38°,38°]和[-31°,31°].当功率密度为4.32 mW/cm2时,两个极化端口均获得70.8%的最高整流效率.     

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。