Transmission Line Impedance Matching Using the Smith Chart (Letters)

A graphical computation method is described for transforming complex load impedances into resistive load impedances using transmission line matching sections. The Smith chart is used even though the characteristic impedance normalizing factor is unknown.     

Transmission Line Transformation Between Arbitrary Impedances Using the Smith Chart (Letters)

A graphical method for transforming between two complex impedances using a single transmission line matching section is described. The Smith chart is used in a mode where the chart normalizing impedance is arbitrary.     

Comments on "Transmission Line Impedance Matching Using the Smith Chart" (Letters)

For the recently discussed problem of R. M. Arnold of finding the characteristic impedance and electrical length of a uniform, loss-free transmission line which transforms a given impedance into another given impedance, an alternate approach using an elementary auxiliary calculation (with no trial and error) has been given in.     

史密斯圆图CAI软件的设计

介绍了用Matlab语言编写的史密斯圆图CAI软件简单易用,具有用户图形界面,能绘出圆图中任意曲线,能演示传输线输入阻抗随距离、频率变化所形成的轨迹以及单支节匹配等求解过程。同时,本文还利用该软件与计算相结合分析了同轴馈电矩形微带贴片天线的电特性,所得结果与有关文献吻合得很好。     

Smith圆图理解和使用的几个关键问题

Smith圆图由三个圆系构成,图形繁杂,是“微波技术”课程教学的重点和难点.笔者在教学过程中,结合内在物理现象的理解,将圆图分为三个层次逐层讲解相关内容,有助于学生们对圆图的深刻理解和熟练掌握.     

基于MATLAB语言的Smith圆图软件设计

Smith圆图是从事微波工程实验和天线设计的重要工具。应用MATLAB作为开发平台研制的Smith圆图应用软件包，使圆图的应用和计算变得更加方便、快捷，该软件具有用户图形界面，简单易用且计算精度高。     

基于MATLAB语言的Smith圆图软件设计

Smith圆图是从事微波工程实验和天线设计的重要工具。应用MATLAB作为开发平台研制的Smith圆图应用软件包 ,使圆图的应用和计算变得更加方便、快捷 ,该软件具有用户图形界面 ,简单易用且计算精度高     

一种基于有耗传输线的动态Smith圆图

基于微波有耗传输线的基本模型,提出了一种针对实际传输线的动态Smith圆图;给出了该圆图详细的推导过程,并通过Matlab对该动态圆图进行了仿真;详细分析了该圆图的特点。该动态圆图完整地包含了阻抗和导纳两个部分,方便于解决微电子中的射频设计问题。     

On the Definitions of Parameters in Ferrite-Electromagnetic Wave Interactions (Letters)

Conflicting definitions of the parameters characterizing the material in ferrite-electromagnetic wave interactions occur in the current literature, as well as do actual sign errors that are difiicult to detect because of the variety of signs appended to the relevant quantities by different authors. A harmonious set of definitions are set out and their consistency illustrated using the case of a uniform circularly polarized plane wave.     

On the Accuracy of the Beam-Wave Theory of the Open Resonator (Letters)

In an interesting paper Erickson has demonstrated how perturbation theory can be used to improve the accuracy of the beam-wave theory of the open resonator. Specifically, two defects of beam-wave theory are considered. The first is that the equiphase surfaces of beam-wave theory are not spherical, the second is that the wave function employed is only an approximate solution to the wave equation.     

基于Smith圆图的13．56MHz天线匹配网络快速设计

根据NXP公司给出的13．56MHz读写器天线匹配网络的拓扑,借助史密斯圆图,给出此网络参数的详细设计过程。较之与NXP公司提出的理论公式计算方法,史密斯圆图法更加快速、简练、直观、易懂,实现了13．56M高频阅读器天线负载阻抗与源阻抗的共轭匹配。     

基于Smith圆图的射频功放电路的设计与分析

基于Smith圆图设计射频匹配电路，提出了大功率射频放大电路的设计方法，采用MRF9060芯片，运用如Pspice和ADS等开发软件，实现了包括直流偏置电路、保护电路、匹配滤波电路以及射频放大电路在内的整体设计，并给出了对系统增益、回波损耗等指标的仿真结果。     

基于Smith圆图的13.56MHz天线匹配网络快速设计

根据NXP公司给出的13.56MHz读写器天线匹配网络的拓扑,借助史密斯圆图,给出此网络参数的详细设计过程。较之与NXP公司提出的理论公式计算方法,史密斯圆图法更加快速、简练、直观、易懂,实现了13.56M高频阅读器天线负载阻抗与源阻抗的共轭匹配。     

Comment on "On the Design of Dielectric Loaded Waveguides" (Letters)

In the above paper, the authors show that, by loading a rectangular waveguide with an E-plane dielectric slab, its theoretical power-handling capacity can be significantly increased. Their conclusion may come as a surprise to experimenters designing high-power E-plane devices such as ferrite isolators or phase shifters. It is a well-known fact that such structures tend to exhibit breakdown at power levels well below those of the empty waveguide.     

Mode Chart for E-Plane Circulators (Correspondence)

The mode chart of the E-plane junction circulator is given. The geometry considered consists of two ferrite disks placed against the narrow walls at the plane of symmetry of a symmetrical 3-port E-plane waveguide junction. It is experimentally found to exhibit two modes. One of these modes has a resonant frequency which increases with the spacing between the two ferrite disks. The other mode has a resonant frequency which decreases with the spacing between the disks. Both modes are independent of the disk spacing when the spacing is large. It is also found that the frequency of both modes is proportional to the thickness of the ferrite disks. Finally, circulators obtained by magnetizing each of the two modes circulate in opposite directions. Experimental results on a circulator obtained in this way are included.     

Computation of the Hecken Impedauce Function (Letters)

The Dolph-Chebyshev impedance function derived by Klopfenstein has discontinuities at the taper ends which introduce unwanted effects in certain applications. The Hecken impedance function is not optimum in the Dolph-Chebyshev sense, but achieves matching without impedance steps. For any bandwidth and maximum magnitude of reflection coefficient in the passband, the Hecken taper is only slightly longer than the optimum taper. Hecken's near-optimum taper is therefore an attractive alternative to the optimum taper when impedance discontinuities are undesirable.