定向耦合器的测试

文章简单介绍定向耦合器的工作原理和主要参数,重点阐述如何应用矢量网络分析仪对其进行测试,并分析了主要的测量误差。     

Tapered Optical Directional Coupler

Tapered velocity optical directional couplers showing 100-percent coupling have been fabricated in thin film form. A computer analysis shows that this type of coupler has greatly improved tolerance properties and does not, in particular, suffer from the severe tolerance restriction placed on velocity synchronism in conventional uniform couplers.     

加窗短槽定向耦合器

在Riblet短槽定向耦合器中的耦合区加入金属谐振窗构成加窗短槽定向耦合器.通过优化谐振窗尺寸,可以有效降低回波损耗,为组建高性能功率合成网络提供便利.本文设计了工作波段为35±1GHz的3dB加窗短槽定向耦合器,回波损耗和隔离度小于-30dB,两个输出端口输出为-3±0.1dB;进一步设计了工作波段为35±1GHz 1:8加窗短槽定向耦合器网络,各端口回波损耗小于～20dB,8个输出端口输出为-9.15±O.15dB.     

Microstrip Spiral Directional Coupler

A new microwave directional coupler with a spiral-shaped construction is described. This coupler is named the spiral coupler and is formed by coiling two edge-coupled lines. Therefore, the size of the coupler can be greatly miniaturized. Furthermore, this coupler can achieve tight coupling much easier than the conventional coupler with edge-coupled lines on account of the multiconductor structure. The spiral couplers with a total length of a quarter-wave were fabricated on alumina ceramic substrates and resulted in 3.5-dB maximum conpling for a 40-mu m strip spacing. The size of the coupler was about one-sixth of the conventional one. The spiral coupler with a total length of three quarter-waves theoretically showed 2.5-dB coupling for a 95-mu m strip spacing on an alumina substrate. The achieved coupling is due to the skillful construction of the spiral. An experimental coupler fabricated on a Teflon substrate confirmed the usefulness of this approach.     

一种宽带高方向性微带定向耦合器

文中设计了一种小型化的具有高方向性的多节微带线定向耦合器。通过将耦合微带线分段处理,得到由一节1/4波长段和两节1/8波长段组合的多段耦合器。非均匀介质微带耦合线中奇偶模相速度的差异导致微带定向耦合器的方向性较差。文中通过在耦合器馈线拐角处采用1/4圆弧提高了方向性。通过优化仿真设计实现了10 GHz耦合器,耦合度为25 dB,并且从6~14 GHz的方向性优于30 dB。与传统的并联耦合线耦合器相比,文中所提出的耦合器具有更小尺寸和更加出色的方向性,且实测和模拟仿真基本一致。     

E面波导3dB耦合器的设计

通过对传统的E面缝隙波导定向耦合器的研究,提出了新的结构和设计方法。通过大量的仿真计算和优化,得出了影响该结构设计的关键尺寸因素;最后,根据仿真结果加工了实物,通过测试,指标满足设计要求,达到预期效果。     

非对称定向耦合器设计

定向耦合器是微波通信领域必不可少的元件之一.平行耦合与分支线耦合是定向耦合器的两种基本形式.重点研究非对称多节定向平行耦合器的设计.根据设计的结构和尺寸,通过HFSS软件进行耦合器结构的仿真.仿真结果表明,设计的定向耦合器可以实现1～4 GHz宽频带下20 dB的耦合度.另外,仿真验证了节支长度对耦合度并不敏感.     

A Plasma Controlled Directional Coupler

A new type of waveguide directional coupler is described which has a discharge tube as the coupling element in the common narrow wall between the guides. The use of the discharge tube allows continuous control of the amount of coupling between the guides. The theory of the coupler is given with curves for designing such a coupler. The paper describes the results obtained from a 3-db coupler. Measurements were made at a frequency of 450 Mc, of VSWR, noise output, and switching speed. These show a VSWR of the order of 1.3 over the control range, and an excess noise temperature with a peak of 20,000/spl deg/K at one value of control current. The coupler is capable of switching up to speeds of 1000 cps.     

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.     

Unilateral Fin Line Directional Coupler

Photonic band gap (PBG) crystals have been used as a perfectly reflecting substrate for many millimeter wave applications. In this work the fin line directional coupler with substrate PBG was analyzed using the TTL - Transverse Transmission Line - method. Compared to other full wave methods the TTL is an efficient tool to determine the coupler characteristics, making possible a significant algebraic simplification of the equations involved in the process. In order to analyze this structure the effective dielectric constant, the attenuation constant and the coupling were determined. The results obtained for this application and the conclusions are presented.     

Power Transfer of a Parallel Optical Fiber Directional Coupler

This letter describes experimental results of a simple optical fiber directional coupler which picks up a small portion of the transmitted power in a main optical fiber transmission line without affecting the characteristics of the main line. This directional coupler consists of two fibers closely parallel in a certain coupling length; an index matching liquid, Si-oil, fills the coupling region. A 50-dB power coupling and 21=dB directivity are measured. Insertion loss is almost negligible. The measured power coupling is much larger than that expected by the simple coupling theory.     

一种表面等离子体激元定向耦合器的传输特性

利用三维全矢量时域有限差分法(FDTD)数值模拟了一种波导间隔金属条高度小于金属层厚度的表面等离子体激元(SPP)定向耦合器,并分析了其在基模传输时的模式场分布和能流密度分布,讨论了耦合长度、最大转移功率与间隔金属条高度的变化关系。结果表明,波导内沿纵向的能流密度在靠近间隔金属条部分的强度更大,有助于提高波导间耦合效率,并且当减小间隔金属条的高度时可以有效缩短定向耦合器耦合长度。这种亚波长定向耦合器结构可以应用在基于表面等离子体激元的集成光路中。     

一种结构新颖的微波高功率定向耦合器

介绍一种结构新颖的微波高功率定向耦合器.该耦合器主线采用波导结构承受功率大,副线采用同轴结构对外连接方便,耦合机构采用单个圆孔实现,整个耦合器设计巧妙,结构简单,便于加工,易于装配,不用调试,指标好,可靠性高,特别适用于高功率、弱耦合、双向取样的场合.     

A Directional Coupler with a Readily Calculable Coupling Ratio

A microwave (X-band) directional coupler consisting of two adjacent lengths of parallel waveguide with a common tantalum wall about for skin depths in thickness has been fabricated and studied. Coupling between the guides is effected through energy transfer via the electromagnetic fields penetrating the thin tantalum foil separating the guides. The coupling ratio of the device can be calculated by a straight-forward procedure to within experimental error (currently a few tenths of a decibel in over 70 decibels).     

一种基于微带均衡器结构的定向耦合器的研究

提出了一种新颖的基于微带均衡器结构的宽频带高定向性微带线定向耦合器,并对该结构进行了理论分析、设计、制作和测量。该结构的新颖之处是通过对耦合度随频率的变化曲线进行均衡得到宽频带特性。该结构采用三电容补偿的微带线定向耦合器结构,并通过在耦合端集成微带均衡器结构实现。测量结果显示,该结构在2.5～3.5GHz工作频带内的耦合度随频率的变化范围约为1dB,隔离度低于-34dB,较之传统结构的微带线定向耦合器均有大幅的提高。测量结果很好地验证了设计方法的正确性。     

单端输入非线性波导耦合器的稳定性及其自开关效应

分析了单端输入非线性光波导耦合器的稳定性，给出了非线性耦合波方程的近似解析解，用近似解析解计算的结果与严格解的结果以及Ａ．Ｔ．Ｐｈａｍ等的近似结果进行了比较，数值分析表明本文的结果比Ａ．Ｔ．Ｐｈａｍ等的结果更接近严格解，还分析了非线性光波导耦合器的调制特性和自开关效应     

A Strip-Line Directional Coupler Utilizing a Non-Homogeneous Dielectric Medium

A 3 dB directional coupler which utilizes nonhomogeneous dielectric media to produce different phase velocities for the even and odd modes of propagation is described. The two output ports are conductively connected to each other as are the input and null ports with dc isolation between the input and both output ports. Well known thin-film techniques can be used to realize the coupler. General coupler equations and design parameters are given along with computer solutions and experimental verification. A minimum return loss of 22 dB was experimentally achieved over a 20 percent bandwidth and 27 dB minimum return loss with equal isolation over the same bandwidth is predicted with the application of simple compensation techniques. It is shown that the coupler maybe used to effect an impedance transformation between the input and output ports; however, the isolation is degraded.     

定向耦合器在调频广播中的应用

1 引言 定向耦合器是无线发射设备得以正常运行不可缺少的基本部件，它在信息传输中的作用亦不容忽视。定向耦合器通常分为几分贝量级强耦合度的定向耦合器和几十分贝量级弱耦合度的定向耦合器两种。功率耦合系数为3 dB强耦合度的定向耦合器称为3 dB耦合器，它主要应用于功率合成与分配。它是调频多工器的重要组成部分，且与带通滤波器及其他一些器件共同完成将多路不同工作频率的调频信号合在一起送至一副天线系统的任务。弱耦合度的定向耦合器常被装在调频发射机各级的输入、输出端的同轴线路中，用来提供测量、监视用的信号。它有正反之…     

一种新型双层微带定向耦合器

提出了一种新型双层微带结构的3 dB定向耦合器.此耦合器由两层带有耦合缝隙和寄生单元的介质板背对背放置.通过增加耦合面积和引入寄生单元补偿电容起到了均衡奇、偶模相速提高了耦合度,实现了宽频的3 dB紧耦合.通过优化设计,在频带范围内,此双层微带定向耦合器的定向性优于普通的耦合微带线定向耦合器.设计结果在450～860 ...     

一种新型宽带环形电桥耦合器设计

传统四端口环形电桥耦合器的带宽只有10%到20%。为了获得更大的带宽,本文提出了一种改进型环形电桥耦 合器。通过额外增加一个隔离臂,新设计可以工作在整个W波段。在此基础上,本文在输入臂上加入了一个切角来改善 输出信号的隔离度。仿真研究结果表明,在75GHz 到110GHz,两输出信号的幅度不平衡度小于0.07dB,相位不平衡度小 于0.37 度。相比于未作切角处理的五端口环形电桥,新设计输出端口的隔离度在全频段内大于15.07dB。改进型耦合器 可以应用于W波段平衡调制器以及其他需要高输出隔离度的W波段功率分配系统。