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Microwave Circuits (microwave + circuit)

Distribution by Scientific Domains
Engineering100%

Selected Abstracts

The state of the art of microwave CAD: EM-based optimization and modeling

INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 5 2010
Qingsha S. Cheng
Abstract We briefly review the current state of the art of microwave CAD technologies. We look into the history of design optimization and CAD-oriented modeling of microwave circuits as well as electromagnetics-based optimization techniques. We emphasize certain direct approaches that utilize efficient sensitivity evaluations as well as surrogate-based optimization approaches that greatly enhance electromagnetics-based optimization performance. On the one hand, we review recent adjoint methodologies, on the other we focus on space mapping implementations, including the original, aggressive, implicit, output, tuning, and related developments. We illustrate our presentation with suitable examples and applications. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010. [source]

Analysis of microwave circuits including lumped elements based on the iterative method

INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 4 2003
H. Trabelsi
Abstract The work presented here introduces lumped elements to an iterative method based on the wave concept combined with the two-dimentional fast Fourrier transformation algorithm known as fast modal transformation (FMT). We extend this method to the analysis of microwave-distributed circuits containing passive or active, linear or nonlinear lumped elements which are characterized by their surface impedance as defined in this article. Simulation results of varactor-tuned filter and phase-shifter circuit examples are compared with the measurement results. Good agreement between simulated and experimental results validates the use of the iterative method for the analysis of planar circuits, including lumped elements. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 269,275, 2003. [source]

Adaptive sampling applied to multivariate, multiple output rational interpolation models with application to microwave circuits

INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 4 2002
Robert Lehmensiek
Abstract A fast and efficient adaptive sampling algorithm for multivariate, multiple output rational interpolation models is presented, which is based on convergents of Thiele type branched continued fractions. The multiple output interpolation model consists of a set of rational interpolants, and each interpolant models one of the output parameters. A single global error function is defined that incorporates all the output parameters, and it is used for the selection of the same set of support points for all the interpolants. The technique is evaluated on several passive microwave structures and compared to previously published results. © 2002 Wiley Periodicals, Inc. Int J RF and Microwave CAE 12: 332,340, 2002. Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mmce10032 [source]

A coupled FDTD-artificial neural network technique for large-signal analysis of microwave circuits

INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 1 2002
S. Goasguen
Abstract We propose a first-order global modeling approach of Monolithic Microwave Integrated Circuits (MMIC) by modeling the active device with a neural network based on a full hydrodynamic model. This neural network describes the nonlinearities of the equivalent circuit parameters of an MESFET implemented in an extended Finite Difference Time Domain mesh to predict large-signal behaviors of the circuits. We successfully represented the transistor characteristics with a one-hidden-layer neural network, whose inputs are the gate voltage Vgs and the drain voltage Vds. The trained neural network shows excellent accuracy and dramatically reduces the computational time in comparison with the hydrodynamic model. Small-signal simulation is performed and validated by comparison with HP-Libra. Then large-signal behaviors are obtained, which demonstrates the successful use of the artificial neural network. © 2002 John Wiley & Sons, Inc. Int J RF and Microwave CAE 12: 25,36, 2002. [source]

Distributed MEMS transmission lines for tunable filter applications

INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 5 2001
Yu Liu
Abstract This paper describes the design and fabrication of a distributed MEMS transmission line (DMTL), used to realize a transmission-line with a voltage-variable electrical length for microwave circuits. The DMTL is a coplanar waveguide periodically loaded with continuously-variable MEMS capacitors. A tunable bandpass filter was designed and fabricated on 700 ,m thick glass substrates using three capacitively coupled DMTL sections as variable shunt resonators. The measured results demonstrate a 3.8% tuning range at 20 GHz with 3.6 dB minimum insertion loss. Issues for future improvement are discussed. © 2001 John Wiley & Sons, Inc. Int J RF and Microwave CAE 11: 254,260, 2001. [source]

Analysis of planar microwave circuits with lumped-elements by CN-FDTD

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2009
Wanchun Tang
Abstract A three-dimensional implementation of the lumped-element by Crank-Nicolson finite-difference time-domain (CN-FDTD) algorithm has been presented in this article. Several examples of planar microwave circuits with lumped resistor, capacitor, and/or inductor are simulated and compared with traditional finite-difference time-domain method and measurements. The accuracy of CN-FDTD implementation for lumped elements in this article has been verified. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 113,116, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23969 [source]

An interpolated spatial images method for the analysis of multilayered shielded microwave circuits

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 9 2008
J. S. Gómez-Díaz
Abstract In this article, an efficient interpolation method is presented to compute the Green's function associated with electrical sources, when they are placed inside cylindrical cavities. The interpolation scheme is formulated in the frame of the spatial images technique recently developed. The original idea was to calculate, for every location of a point electric source, the complex values of the electric dipole and charge images, placed outside the cavity, to impose the appropriate boundary conditions for the potentials. To considerably reduce the computational cost of the original technique, a simple interpolation method is proposed to obtain the complex values of the images for any source location. To do that, a rectangular spatial subdivision inside the cavity is proposed. Each new subregion is controlled by means of the exact image values obtained when the source is placed at the four corners of the region. The key idea is to use a bilinear interpolation to obtain the image complex values when the source is located anywhere inside this subregion. The interpolated images provide the Green's functions of the new source positions fast, and with high accuracy. This new approach can be directly applied to analyze printed planar filters. Two examples with CPU time comparisons are provided, showing the high accuracy and computational gain achieved with the technique just derived. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2294,2300, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.23683 [source]

MMIC's characterization by very near-field technique

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2004
L. Nativel
Abstract This paper shows a method to characterize microwave circuits using a near-field scanning microscope. Applied on various samples, it shows good resolution and weak disturbance for ICs operating with very common microwave components. Here, it is applied in an industrial surrounding to characterize the Bluetooth CMOS power amplifier. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 209,213, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20096 [source]