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Admittance Matrix (admittance + matrix)

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Engineering100%

Selected Abstracts

Generation, modeling, and analysis of CCII-based gyrators using the generalized symbolic framework for linear active circuits

INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 3 2008
Ramy A. Saad
Abstract In this paper, CCII-based gyrators are synthesized, modeled, and analyzed using the generalized symbolic framework for linear active circuits. The systematic synthesis method using admittance matrix expansion, included in the framework, is applied to generate optimized nullor,mirror descriptions for the gyrator. The resulting CCII-based circuit representations for the gyrators, obtained from mapping nullor,mirror pairs in the ideal realizations with equivalent second-generation current conveyors (CCIIs), can be classified into two topologies according to the type of the CCII terminals handling the gyrator input and output signals. In topology I, the gyrator input and output terminals are CCIIs Y,Z -terminals, whereas in topology II, the gyrator input and output terminals are CCIIs X -terminals. The parasitic components within the synthesized circuits, associated with the actual CCIIs, are modeled and included in their expanded admittance matrices. Exact non-ideal analysis for two circuits belonging to the two topologies, involving the reduction of their expanded admittance matrices to port admittance matrices, is then carried out to investigate the practical functional performance for these circuits at their ports. The non-ideal performance analysis based on the CCII actual parasitic elements indicates that, from a practical perspective, the CCII-based gyrator circuits belonging to topology I are more efficient and suitable for the gyrator applications than those belonging to topology II in terms of bandwidth and operation at high frequencies. SPICE simulations are included to demonstrate the analytical results for the comparison between the practical performances of the two circuit topologies. Copyright © 2007 John Wiley & Sons, Ltd. [source]

A new approach for using the pathological mirror elements in the ideal representation of active devices

INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 2 2010
Ramy A. Saad
Abstract This paper is adopting a new approach to investigate the capabilities of pathological mirror elements in the ideal representation of active building-blocks and shows that the voltage mirror (VM) and current mirror (CM) are the basic pathological elements. The descriptions for the floating mirror elements in the nodal admittance matrix (NAM), using infinity-variables, are derived. The descriptions for nullator and norator using infinity-variables in the NAM are shown to represent special cases from the derived descriptions of the floating VM and the CM, respectively. Hence, new representations for the nullator and norator in terms of the floating VM and CM, respectively, are obtained. A systematic procedure for the derivation of pathological configurations to ideally represent various analog signal-processing properties featured by active building-blocks is presented. This systematic approach became plausible by virtue of the versatility offered by the NAM descriptions of floating mirror elements. Novel pathological configurations ideally describing most popular signal-processing properties that involve differential or multiple single-ended signals; like conversion between differential and single-ended voltages, differential voltage conveying, current differencing, differential current conveying, and inverting current replication; are derived systematically using this procedure. The resulting pathological configurations are shown to be constructed mainly using mirror elements and hence the capabilities of the mirrors as basic pathological elements are further demonstrated. Pathological representations for some active building-blocks, using the derived pathological sections, are presented as application examples. Copyright © 2008 John Wiley & Sons, Ltd. [source]

The computation of the input impedance of a biconical antenna by means of a method of segmentation based on 3D finite elements

INTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 5 2003
José Ma Gil
Abstract The analysis of structures with complex geometries leads to the use of three-dimensional numerical methods. Such devices can be unmanageable unless a segmentation technique is applied. In this work, a hybrid 3D finite-element-mode matching method, based on the generalized admittance matrix (GAM) is applied to the computation of the input impedance of a biconical antenna fed by a cylindrical cavity loaded with resonant slots and matched by a coupling network composed of three multi-ridge circular irises and sections of circular waveguides. The structure is segmented into regions which are analysed separately and, by means of linking the partial matrices calculated, the generalized scattering matrix (GSM) is obtained. In order to validate the method, numerical results and measurements are compared. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Frequency/time-domain modelling of 3D waveguide structures by a BI-RME approach

INTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 1 2002
P. Arcioni
This paper presents a full wave method for the determination of the mathematical model of a 3D waveguide structure in the form of the pole expansion in the s -plane of its generalized admittance matrix. The method is based on a boundary integral-resonant mode expansion approach. By the introduction of appropriate state-variables, the method leads to the pole expansion by solving a linear generalized eigenvalue problem, like in the well-known techniques used up to now in frequency/time domain modelling based on finite difference or finite element methods. With respect to these methods we have the advantage of a significant reduction in both memory allocation and computing time. Two examples show the accuracy of the results and the efficiency of the method. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Full-wave modeling and optimization of Bøifot junction ortho-mode transducers

INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 4 2008
Jorge A. Ruiz-Cruz
Abstract The full-wave design of broadband ortho-mode transducers based on the Bøifot junction has two main aspects: an efficient analysis method and a design process divided into tasks with relatively low computational effort. In the analysis part, a rigorous mode-matching technique has been developed to obtain the generalized admittance matrix of the Bøifot junction. The other elements of the device are also analyzed by mode-matching. With respect to the design, the proposed procedure starts with the optimization of the individual building blocks of the device. Their interaction is also taken into account in a systematic process. The analysis and design methods have been validated with other numerical methods and an experimental prototype. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008. [source]