Constant-Frequency Synthesis of Lossy Microwave Two-Ports (Short Papers)

At a fixed frequency, every linear time-invariant two-port can be described by its scattering matrix, whose elements represent eight real parameters. In this paper, it is proved that every Iossy (linear, time-invariant) two-port can be canonically synthesized by eight "elementary" two-ports, which are characterized by one parameter only. Moreover, these elementary two-ports are passive and realizable in the microwave region. The synthesis is performed in the form of a cascade structure (with one "side arm" for the nonreciprocal case). Explicit formulas for the parameters of the elementary two-ports are derived.     

Automatic analysis of two-port active microwave network

A new six-port ANA technique and its application in analysing an active microwave network are discussed. The reported isolated dual-six-port ANA (IDSPNA) provides a simple and powerful means to determine any two-port network scattering matrix. Computer simulation and experimental results for MIC amplifiers are presented.     

Semi-lossy two-port and a theorem concerning RLCn networks

By `semi-lossy two-port? is meant a passive two-port being dissipation-free for some particular form of excitation. Some properties of these two-ports are derived using the impedance matrix. The meaning of these results for the scattering formalism is given. Furthermore a theorem is derived concerning networks built up of passive (ideal) transformers, inductors, capacitors and resistors.     

复合多端口网络的参数矩阵计算

一些电路教材对二端口网络的连接方式进行了介绍并给出复合二端口参数矩阵的计算方法。多个二端口的任意连接可以构成复合多端口网络,其参数矩阵也可以由构成它的二端口网络的参数矩阵表示。本文类比了电路网络中的关联矩阵,建立描述二端口和复合多端口关系的端口关联矩阵,并利用二端口的特性和串并联的特点,给出了求解复合多端口网络参数矩阵的新方法。     

General Purpose Programs for the Frequency Domain Analysis of Microwave Circuits

This paper describes microwave circuit analysis programs techniques for general purpose which perform frequency domain analyses. Differing techniques used in two programs are described. The first uses transfer matrix analysis and is limited to networks having tree structured topologies and two-port devices such as transmission lines, stubs and lumped elements. It runs on a time-shared computer and is used for interactive design. The second program can analyze any linear network including those with multiport elements such as coupled transmission lines. This uses a nodal representation for the circuit and relies on inverting an admittance matrix to perform the analysis. In the first program the user describes his circuit in terms of topology as well as circuit elements. By this technique, a considerable reduction in computer size needed to run this program is effected. A 60 element circuit can be run on a commercial time-sharing service with less than 6K words of available core. The second program requires a large computer; for example, 32K words or core storage are required to analyze a 50 node circuit.     

Efficient Technique for the Cascade Connection of Multiple Two-Port Scattering Matrices

There are several practical applications in microwave engineering that require the cascade connection of multiple two-port scattering matrices. Many microwave devices are analyzed by segmenting the structure into small building blocks (steps, resonators, lines, etc.) that are characterized by means of the generalized scattering matrix. In order to obtain the reflection and transmission parameters of the entire structure, the scattering matrices of all the building blocks must be cascaded. Traditionally, the conversion of the scattering matrices to ABCD or T matrices has been used in order to perform the cascade connection. An alternative to this procedure is to perform a recursive connection by pairs of the scattering matrices. In this paper, we present a new technique for the efficient cascade connection of N monomodal or multimodal scattering matrices that reduces the computation time by 35% when compared to the cascading by pairs, and by 75% when compared with the use of ABCD matrices.     

Two-port noise and impedance measurements for two-terminal deviceswith a resonant tunneling diode example

A two-port technique is presented for determining the circuit elements and noise sources of the equivalent circuit of a two-terminal device at microwave frequencies. The two-terminal device is connected as a two-port so that intrinsic and parasitic circuit elements can be obtained from full two-port S-parameter measurements. This measurement does not require one of the two contacts to be grounded, which makes it particularly well suited for the characterization of integrated devices where parasitic elements become important and cannot be easily calculated. The noise of the device is measured by employing a noise-figure meter and the intrinsic noise is computed from the measured terminal noise. As an example, the impedance and noise elements of a resonant tunneling diode (RTD) are measured over frequency ranges of 2-8 and 2-4 GHz, respectively     

An Optimization Technique for Lumped-Distributed Two Ports

A frequency domain direct efficient analysis and an optimization technique of a large class of lumped-distributed networks containing active elements are presented. Sensitivity and Hessian matrix calculations are performed using truncated Taylor series expansion of two-port parameters of subnetworks. An interactive computer program was developed to demonstrate the application of the method. Examples of network optimization are included to illustrate the powerfuless of the technique.     

Spherical-wave source-scattering matrix analysis of coupled antennas; A general system two-port solution

Expressions are given for the coupling between two antennas in terms of each antenna's spherical-wave source-scattering matrix. A comparison with the "classical" scattering matrix representation is given in sufficient detail to permit conversion back and forth between the source-scattering matrix and the classical scattering matrix. Expressions for the transmission formulas, showing two different expressions corresponding to reversing the direction of propagation are given. However, if both antennas are reciprocal with equal characteristic waveguide impedances, then the two-port scattering matrix is a symmetric matrix.     

NOVA (Network Optimization Via Adjoints) (Computer Program Descriptions)

Least pth optimization of reflection coefficients and/or transducer gain of two-port microwave networks.     

Notes on the Conjugate Matched Two-Port As an UHF Amplifier (Short Papers)

Because of the relative simplicity of measurement of scattering parameters of active two-ports at frequencies up to the lower microwave region, investigations have been made into the application of these parameters to the design of UHF amplifiers. The theory of generalized scattering parameters has been developed by Kurokawa, applied to two-port power-flow analysis by Bodway, and used in the design of a single-stage UHF amplifier by Froehner. In this last paper, the bandwidth limitations imposed by the matching networks were not considered, nor was the capacitive matching arrangement to a purely resistive load fully developed. Both of these topics are the subject of this short paper, in which the relevant design expressions are also given.     

Linear passive networks: Functional theory

Linear passive time-variable networks are investigated primarily through the use of distributional kernels as applied to the scattering matrix treated in the time domain. Necessary and sufficient conditions for passivity are obtained, and the scattering matrix is shown to be a measure satisfying an energy form constraint. Lossless constraints pertinent to synthesis are developed while networks consisting of a finite number of circuit elements are considered in some detail. Examples illustrating interesting behavior are presented.     

微波网络[S]参数应用实例

散射矩阵即[S]参数是描述微波网络特性的一种重要的矩阵形式,也是微波网络的特色之一。对散射矩阵概念的理解与应用是本科微波技术课程微波网络部分的一个重点和难点。本文以微波基本元件——3dB分支线定向耦合器为例,从它的[S]参数出发探究其工作性质,并给出了具体的工程应用实例,借此加深学生对[S]参数的理解,掌握用[S]参数分析问题的方法和能力,同时也可使学生了解3dB分支线定向耦合器的各种实用价值。     

Cascade of simple commensurate uniformly distributed RC four-port unit elements

The simple commensurate URC? four-port unit element is defined, and the transfer matrix for a cascade of these elements is derived. It is shown that certain terminal connections will produce a two-port network with two short-circuited admittance parameters (transfer and one driving-point) which are rational in the normalised URC? complex frequency variable t = tanh ?s. The real-frequency transfer response is investigated, and typical responses for networks containing two elements are presented.     

非对称模板点格神经网络的动态特性研究

本文利用了矩阵Ｏｓｔｒｏｗｓｋｉ与ｂＲＡＵＥＲ对角占优之条件得到了点格神经网络平衡点存在的充分必要条件，然后利用Ｏｓｔｒｏｗｓｋｉ圆盘定理与Ｂｒａｕｅｒ卵形定理得到了点格神经网络的完全稳定性条件，这为非对称 模板的点格神经网络提出一和中新的研究方法。     

Generalized scattering matrix of generalized two-portdiscontinuities: application to four-port and nonsymmetric six-portcouplers

A field theory analysis of multiport, multidiscontinuity structures based on the generalized scattering matrix (GSM) of a generalized two-port discontinuity concept is presented. The analysis can be used in any structure equipped with any number of input and output ports, and results in substantial simplifications over previous analyses. The GSMs of generalized two-port discontinuities can also be cascaded with the same procedure as the two-port discontinuities and can be used to determine the electromagnetic field and the Poynting vector at every point of the structure. The GSM of the generalized two-port technique is used to analyze four-port and nonsymmetric six-port branch-waveguide directional couplers, and good agreement between the theoretical results and experimental data is obtained     

Nonreciprocal Two-Ports Represented by Modified Wheeler Networks

The extension of the (reciprocal) modified Wheeler network to include the more general nonreciprocal two-port is given. This representation is derived via a known decomposition of the general nonreciprocal network into two portions, one reciprocal, the other nonreciprocal. The reciprocal portion is then taken as the modified Wheeler network. Recombination of the elements results in the desired representation which is constituted of a minimum number, i.e., of eight, passive elements. Each of these is a natural idealization of a physical microwave component. Since six of the elements belong to the class of "bilaterally matched" networks, some of the properties of this class are discussed. Two of the bilaterally matched elements embody the nonreciprocal properties of the network: a one-way attenuator and a one-way phase-shifter. Many of the characteristics of the (reciprocal) modified Wheeler network carry over directly to this nonreciprocal representation. The microwave measurement of the network parameters is also indicated.     

微波双工器电路综合

近年微波滤波器多项式综合技被广泛用于微波滤波器的设计,将此技术由双端口网络推广至三端口网络可以实现微波双工器的综合。根据微波网络技术,可以推导得到微波双工器电路等效y参数与S参数的关系,进而得到微波双工器散射参数s11,s21,s31与两个通道单通带微波滤波器散射参数s11,s21的关系。应用推广后的微波双工器电路综合技术可以实现微波双工器的精确、快速综合。经过对比发现,微波双工器多项式综合结果与微波双工器电路建模仿真响应吻合度很好。     

关于正弦稳态功率传输的讨论

正弦稳态最大功率传输定理是电路教学中的重要内容。本文讨论了在给定电源内阻抗和负载阻抗的情况下,通过在电源和负载之间接入一个二端口网络,以达到实现阻抗变换的目的,从而实现负载阻抗获得的功率最大;推导了在电源和负载之间接入由动态元件构成的对称互易二端口网络实现负载功率最大的传输矩阵计算公式;并对二端口网络的结构作了进一步的说明。上述讨论结果可供讲授电路课程的教师参考。