Reduction of electromagnetic field coupling to microwave microstrip circuits

The signals induced by an external electromagnetic field along a microstrip line on a multilayered dielectric substrate were studied. The main target of the work is not to introduce a new technique of study but to search for suitable combinations of the structural and geometrical characteristics of the printed geometry whereby the electromagnetic interference of the external field to the circuit would be reduced. This reduction is desirable in all modern applications. The results derived prove that this object can be achieved at high frequencies and when the substrate is multilayered.     

A computer architecture laboratory course using programmable logic

This paper describes the software and hardware developed for the laboratory component of a junior/senior level computer architecture course. The principal feature of this course is that students are required to design and build their own computers using programmable logic devices (PLDs). The students use a simple register transfer language (CURTL) with a simulator and commercial PLD tools for their design activity. A graphical PC based debugging tool provides the I/O and main memory for the student built computers     

A hands-on experimental laboratory for undergraduate courses in automatic control

An experimental laboratory for undergraduate courses in automatic control has been created at the Politecnico di Milano, Milano, Italy, to provide students with an environment where theoretical concepts can be applied, and the "look and feel" of a real-world problem, though small and simple, can be experienced. The laboratory is meant both for the basic course, titled Fundamentals of Automatic Control, and for advanced ones. Peculiar to the setup is the large number of students involved, with 72 experimental workstations being managed simultaneously. This paper describes the design, implementation, and use of the laboratory until now, dealing with the present experimental setup and the integration of laboratory assignments and lectures.     

Georgia tech information security center hands-on network security laboratory

An undergraduate internetwork, security-teaching laboratory, which includes both defensive and offensive security laboratory experimentation, is described. This laboratory is oriented toward an introductory internetworking security class and is intended to complement more theoretical network security classes while sparking student interest. The laboratory is unique in that it uses an isolated laboratory network that provides a simple model of the Internet, including an enterprise network component, a university component, a "good" Internet service provider, and a "bad" Internet service provider. This setup is in contrast to typical educational laboratories, which use only a few physical computers with virtual machines. All of the laboratory assignments are available on the Internet for general community use and modification (the Internetwork Security Class Home Page is available at http://users.ece.gatech.edu//spl ap/owen/).     

A modern course in microwave engineering

A two-semester course in microwave engineering at the senior/first-year-graduate level has been developed over the last seven years at the University of Massachusetts, Amherst, MA. This course has a laboratory, and is modern in the sense that it includes contemporary topics (such as planar transmission lines, components, and circuits), the use of computer-aided design techniques, and access to state-of-the-art microwave laboratory test equipment. The course emphasizes fundamental principles and concepts, but also contains a large amount of design-oriented material with current ABET requirements in mind. The lecture material for this course has been refined to the point where a textbook is in the final stages of preparation     

A laboratory course on fuzzy control

In this paper we describe a new control laboratory course at The Ohio State University. Students execute a series of laboratory exercises, for a variety of processes, implementing fuzzy control, adaptive fuzzy control, and other intelligent control techniques, with a particular focus on fuzzy control. Fully instrumented independent testbeds in the laboratory emphasize several sensing and actuation technologies. Both senior undergraduates and graduate students take the course and several have used the experience, coupled with research that they have conducted with our industrial sponsors, to obtain positions in industry working on intelligent control     

Propagation of picosecond pulses in superconducting microstrip interconnections on integrated circuits

Studies on the propagation of picosecond pulses in coupled microstrip line interconnections on silicon integrated circuit substrates are presented. The effects of conductor and dielectric losses in the transmission line on the distortion, delay and attenuation of picosecond pulses are studied in detail. A direct comparison is made with the propagation characteristics of interconnects using ordinary metals and high-temperature superconductors such as YBa₂Cu₃O₇. The results generally show the advantages of using high-temperature superconductor tracks on low-loss integrated circuit substrates such as GaAs. However, even in this case, geometrical dispersion can cause distortion on the pulses and it is therefore an important factor to be considered.     

Finite difference time-domain analysis of planar microwave circuits

Contents The application of finite difference time domain analysis techniques to planar microwave integrated circuit design is discussed. It is shown that using this technique, three-dimensional discontinuity problems in planar microstrip and coplanar circuits can be analyzed in a full-wave approach.

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Finite-Differenzen-Analyse von planaren Mikrowellen-schaltungen im Zeitbereich

Übersicht Es wird die Anwendung der Finiten-Differenzen-Analyse elektromagnetischer Felder im Zeitbereich auf den Entwurf integrierter Mikrowellenschaltungen diskutiert. Es wird gezeigt, daß durch Anwendung dieser Technik eine Lösung der Beschreibungsprobleme für dreidimensionale Schaltkreis-Diskontinuitäten in planarer Mikrostreifenleitungstechnik und in koplanarer Leitungstechnik unter Berücksichtigung der vollen Welleneigenschaften gefunden werden kann. Verschiedene Beispiele von Analysen planarer Mikrowellenbauelemente werden diskutiert und die Ergebnisse mit Messungen verglichen.

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Dedicated to Prof. Dr.-Ing. Herbert Döring on the occasion of his 80th birthday     

Broadband and compact impedance transformers for microwave circuits

Most microwave circuits and antennas use impedance transformers. In a conventional power amplifier, large number of inductors and capacitor or transmission line sections are use to realize an impedance transformer. This article presents an asymmetric broadside-coupled microstrip TLT (transmission line transformer) on the GaAs substrate. This matching network can be easily implemented using any monolithic microwave integrated circuit (MMIC) process supporting multilevel metallization.     

System-level microwave design: radar-based laboratory projects

Two laboratory projects-a Doppler radar and a synthetic aperture radar (SAR)-designed to augment traditional electromagnetics education are proposed. The projects introduce students to component and system level design and expose them to modern computer-aided design (CAD) tools, microstrip and surface mount fabrication technologies, and industry standard test equipment and procedures. Additionally, because the projects result in a working radar system, students gain new enthusiasm for the electromagnetics discipline and directly see its relevance in the engineering field. Implementation of these laboratories within the curriculum have proven to be highly motivational and educational and have even contributed to increased enrolments in upper division electromagnetics courses.     

A high speed three-zone distance relay using digital circuits

Polyphase distance relaying using solid state components has been accepted in general as a secondary protection for EHV/UHF lines. It is not surprising that in developed countries solid state relaying has gained popularity as the primary means of protection with 100% discrimination and reliability. The older schemes using rectifier bridge phase detectors are not so sensitive and are also slow in operation, especially near boundary conditions. This paper deals with a new relaying scheme, using digital circuits with CMOS logic, which does not use a separate starting unit, nor an electromechanical unit for zone changing. The present relaying scheme with mho and elliptic starting characteristics can give modified mho characteristics with blinders or a quadrilateral characteristic by simply changing the measuring circuit and signal processing unit. This relay has been designed, fabricated and tested on a ‘dynamic test bench’ which has also been designed and fabricated in this laboratory. It is expected that this relaying scheme may prove to be better than the existing ones.     

浅谈天馈线电压驻波比对微波电路的影响

天馈线电压驻波比是微波电路运行的重要指标，通过典型事例来阐述天馈线电压驻波比的劣化对微波电路的影响，并根据多年实践经验提出天馈线维护需注意的事项。     

Short-term project on microwave passive planar circuits: aneducational approach

The paper presents a short-term project on microwave planar circuits proposed to undergraduate students at Universite Catholique de Louvain, Belgium, in the frame of a basic course on microwave engineering. It helps the students to familiarize with all circuit aspects at microwaves and millimeter waves: they design, analyze, realize, and measure a planar passive component operating in the frequency range 0-40 GHz. Their attention is especially focused on microwave concepts: modeling a transmission line behavior and its limitations, spurious effects at high frequencies (radiation, coupling, and reactive behavior from higher order modes), influence of etching, mechanical tolerances, and wide-band behavior. The educational relevance of the project results from the opportunity given to the students to obtain in a very short period of time an actual component by combining up-to-date theoretical models, modern etching facilities, and measurement equipment, like in industry. Such an opportunity is rather unique and of prime interest for their possible future career in the growing area of microwave and millimeter wave communications     

Method of moments modelling of cylindrical microwave integrated circuits interconnections

In this paper, a numerical technique suitable for characterizing a wide variety of interconnection configurations printed on cylindrical surfaces, is presented. The interconnection lines may have either finite or infinitesimal cross‐sections. To model cylindrical interfaces, suitable space‐domain integral equations are formulated to represent the potential on conductors and electric field at dielectric interfaces. The solution of the integral equations is then obtained numerically by applying the method of moments (MOM). The objective of this approach is to determine the capacitance matrix of cylindrical interconnection systems with different configurations. From the capacitance matrix, other quantities such as characteristic impedance, coupling coefficient and effective permittivity can be determined. The numerical technique described in this paper is implemented as a general computer program. Various circular cylindrical as well as elliptical cylindrical structures have been solved including microstrip lines and coplanar waveguide lines. The results obtained compare very well with other published data. Copyright © 2004 John Wiley & Sons, Ltd.     

Using the Fourier series in a circuits or DSP laboratory

Laboratory experiments on circuits that exhibit transient effects are usually performed with a periodic input signal (like a square wave). Three experiments on a resistor capacitor (RC) filter using transient analysis and the solution of a first-order differential equation are described. The results according to a Fourier analysis are then reinterpreted. The similarities and differences in the results from the two theories provide a better understanding of both. Also, using Fourier analysis introduces the basic strengths and weaknesses of discrete signal processing. Further additions to this laboratory are discussed and include (1) the addition of more first-order linear circuits; (2) the addition of second-order (and higher-order) linear circuits; (3) the processing of all data in the frequency domain; and (4) the study of nonlinear circuits     

A computer-aided design of EMC microstrip dipole arrays using nonlinear optimization techniques

This paper describes a method for designing electromagnetically coupled (EMC) printed dipole arrays. The advantages of EMC dipoles include greater bandwidth, higher efficiency, and an easier match to the feed lines, when compared to classically fed printed antennae. The excitation mechanism is provided by a strip transmission line embedded inside the substrate which couples energy parasitically to the microstrip antenna. Electromagnetically coupled microstrip dipoles have been investigated by empirical or approximate analysis techniques. As a result an approximate model has been derived for microstrip dipoles. The method is based on the method of moments solution to an integral equation derived from the approximate Green function for a grounded dielectric slab. The element lengths and offsets and the stub length of the EMC dipole array are determined by the direct search optimization method of Hooke and Jeeves. To show the feasibility of the proposed method, a mathematical formulation and numerical results are presented for Chebyshev arrays. © 1998 Scripta Technica, Electr Eng Jpn, 125(4): 60–66, 1998     

Numerically distributed circuit parameters model on microstrip transmission line circuits and its application on CAD

A new numerical model of microstrip transmission line circuits in terms of distributed circuit parameters is here illustrated. Based on full‐wave electromagnetic results, the extraction methods of these distributed circuit parameters on different types of microstrip transmission line circuits are introduced. As a preparatory experiment, an improved CAD method using this model is tested on microstrip low‐pass filter. Copyright © 2003 John Wiley & Sons, Ltd.