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Showing papers in "International Journal of Microwave and Millimeter-wave Computer-aided Engineering in 1994"


Journal ArticleDOI
TL;DR: In this paper, a comprehensive review of the modes and the radiation characteristics of open dielectric resonators (DRs) of different shapes, such as cylindrical, spherical, and rectangular, is presented.
Abstract: Open dielectric resonators (DRs) offer attractive features as antenna elements. These include their small size, mechanical simplicity, high radiation efficiency due to no inherent conductor loss, relatively large bandwidth, simple coupling schemes to nearly all commonly used transmission lines, and the advantage of obtaining different radiation characteristics using different modes of the resonator. In this article, we give a comprehensive review of the modes and the radiation characteristics of DRs of different shapes, such as cylindrical, cylindrical ring, spherical, and rectangular. Further, accurate closed form expressions are derived for the resonant frequencies, radiation Q-factors, and the inside fields of a cylindrical DR. These design expressions are valid over a wide range of DR parameters. Finally, the techniques used to feed DR antennas are discussed. © 1994 John Wiley & Sons, Inc.

861 citations


Journal ArticleDOI
TL;DR: In this paper, accurate measurement-based models derived from measured S-parameters of passive circuit elements which include inductors, thin-film resistors, interdigital and MIM capacitors, via holes, and airbridges for use in the computer-aided design of monolithic microwave integrated circuits (MMICs).
Abstract: This article presents accurate measurement-based models derived from measured S-parameters of passive circuit elements which include inductors, thin-film resistors, interdigital and MIM capacitors, via holes, and airbridges for use in the computer-aided design of monolithic microwave integrated circuits (MMICs). The thru-reflect-line (TRL) calibration method is employed to accurately measure the S-parameters of the passive elements. Some of the models are scalable for different substrate thicknesses and substrate dielectric constant values as they are based on microstrip line theory. © 1994 John Wiley & Sons, Inc.

27 citations


Journal ArticleDOI
TL;DR: In this article, a classical negative impedance converter (NIC) has been terminated in an RLC one-port specially designed to compensate for the parasitics of the active and passive elements.
Abstract: This article presents a method for synthesizing a negative resistance in MMIC technology. The circuit employed is a classical negative impedance converter (NIC) that has been terminated in an RLC one-port specially designed to compensate for the parasitics of the active and passive elements. The procedure, which effectively translates a nonideal NIC design task into a well-defined one-port synthesis problem, is demonstrated in computer simulation for a four-transistor MMIC network which achieves a purely real input resistance of −100 Ω over 1.5–2.5 GHz. An important application for NIC-based circuits of this type is in the design of microwave active filters. © 1994 John Wiley & Sons, Inc.

22 citations


Journal ArticleDOI
TL;DR: In this paper, the effective dielectric constant of a microstrip line on anisotropic substrates made of r-cut sapphire crystals was derived for the first time.
Abstract: Simple and correct formulas are derived for calculation of an effective isotropic dielectric constant, which characterizes the wave propagation in microstrip lines on anisotropic substrates made of r-cut sapphire crystals. The r-plane is extensively used for epitaxial growth of high-Tc superconductor YBa2Cu3O7 films as applied to microwave integrated circuits. In contradistinction to previous models developed for z-cut sapphire, the nondiagonal dielectric permittivity tensor of r-cut sapphire is used. The effective dielectric constant of a microstrip line on r-cut sapphire substrate is found as a function of the strip-line geometry and the orientation of the crystallographic axes with respect to the symmetry plane of the microstrip line

17 citations


Journal ArticleDOI
TL;DR: In this paper, a full-wave, space-domain moment method was developed for the analysis and circuit characterization of passive microstrip elements (in an open environment) at microwave frequencies.
Abstract: A new full-wave, space-domain moment method implementation is developed for the analysis and circuit-characterization of passive microstrip elements (in an open environment) at microwave frequencies. The computational time and memory requirements are significantly reduced by filling the moment matrix efficiently utilizing closed-form Green's functions and symmetries in the problem formulation, such that a circuit of moderate electrical size can be analyzed in reasonable time on a personal computer. © 1994 John Wiley & Sons. Inc.

14 citations


Journal ArticleDOI
TL;DR: In this paper, several miniature bandpass filters were developed by accurate modeling of experimental and computer-generated coupling data of hairpin-line microstrip line resonators on high dielectric constant (er = 80 and 90) substrate.
Abstract: Several miniature bandpass filters have been developed by accurate modeling of experimental and computer-generated coupling data of hairpin-line microstrip line resonators on high dielectric constant (er = 80 and 90) substrate. The materials are temperature stable and of high quality factor. The experimental results show excellent filter shapes and some novelty of the design approach. Besides the experimental results, this article also presents the curves and semiempirical models for the coupling coefficients between hairpin-line resonators for two different dielectric materials and thicknesses. The method and the results will be useful in realizing compact planar filters for cellular radio, global positioning systems and superconducting microstrip filters.

13 citations


Journal ArticleDOI
TL;DR: In this article, an accurate method of moments (MoM) model is developed and implemented for the analysis of the linearly tapered slot antenna (LTSA), which employs an unequal size reactangular sectioning for conducting parts of the antenna.
Abstract: An accurate Method of Moments (MoM) model is developed and implemented for the analysis of the linearly tapered slot antenna (LTSA). The model employs an unequal size reactangular sectioning for conducting parts of the antenna. Piecewise sinusoidal basis functions are used for the expansion of conductor current. The effect of the dielectric is incorporated in the model by using equivalent volume polarization current density and solving the equivalent problem in free space. The feed section of the antenna including the micro-stripline is handled rigorously in the MoM model by including slotline short-circuit and microstripline currents among the unknowns. Comparison with measurements is made to demonstrate the validity of the model for both the air case and the dielectric case. Numerical results for the effect of the dielectric permittivity are presented.

11 citations


Journal ArticleDOI
TL;DR: The IE3D electromagnetic simulator as discussed by the authors is based on an integral equation, a method-of-moment formulation for a full-wave solution of three-dimensional (3D) arbitrarily shaped structures in microwave and millimeter-wave integrated circuits (MMIC), high temperature superconductor (HTS) circuits, microstrip antennas, RF printed circuit boards (PCB), and high speed digital circuit packaging.
Abstract: A general purpose CAD tool, the IE3D electromagnetic simulator is presented in this article. The simulator is based on an integral equation, a method-of-moment formulation for a full-wave solution of three-dimensional (3D) arbitrarily shaped structures in microwave and millimeter-wave integrated circuits (MMIC), high temperature superconductor (HTS) circuits, microstrip antennas, RF printed circuit boards (PCB), and high speed digital circuit packaging. The primary solution of the simulator is the current distribution on a metallic structure in an environment of multilayered substrates on infinitely extended ground plane. The circuit parameters of the structure in either S-parameter form or RLC-SPICE equivalent circuit form is extracted from the solved current distribution. The simulator consists of an MS-Windows-based layout editor, a schematic editor, an electromagnetic simulator, and a post processor. The simulator can perform stand-alone electromagnetic simulation and optimization and mixed electromagnetic and nodal analysis. Simulation results for structures in various high frequency and high speed domains are presented and compared to measured results. © 1994 John Wiley & Sons, Inc.

11 citations


Journal ArticleDOI
TL;DR: In this paper, the finite difference method (FDM) is applied to the analysis of microwave integrated circuit (MIC) components that are based on the coplanar waveguide geometry.
Abstract: The finite difference method (FDM) is applied to the analysis of microwave integrated circuit (MIC) components that are based on the coplanar waveguide geometry. Effective dielectric constant, attenuation due to dielectric loss, and line impedance are calculated for open and shielded MICs as functions of transmission line dimensions and material parameters. The FDM is shown to be a practical engineering CAD tool for detailed examination of MICs having an arbitrary number of conductors and lossy dielectric layers, including field effect transistors.

10 citations


Journal ArticleDOI
TL;DR: In this article, a dielectric substrate backed by a conducting plane is designed for radiation of a circularly polarized wave, and the guided wavelength of the crank lines is evaluated by an iterative technique based on the numerically determined current distribution.
Abstract: Crank lines on a dielectric substrate backed by a conducting plane are designed for radiation of a circularly polarized wave. The guided wavelength of the crank lines is evaluated by an iterative technique based on the numerically determined current distribution. It is found that the crank lines designed with the final guided wavelength can radiate a circularly polarized main beam in the broadside direction. The frequency responses of the radiation characteristics are also presented.

7 citations



Journal ArticleDOI
TL;DR: In this paper, an active microstrip patch antenna with a GaAs MESFET on the patch periphery and the circuit acting as a self-oscillating radiating element is presented.
Abstract: This article discusses the application of a synthesis method for, and the subsequent experimental characterization, of an active microstrip patch antenna. The active antenna incorporates a GaAs MESFET on the patch periphery and the circuit acts as a self-oscillating radiating element. The MESFET and the antenna are mounted on the same side of the circuit, thereby preserving the conformal nature of the structure. The synthesis approach described is based on the method of harmonic balance and allows optimal FET terminations to be selected for a predefined, added power at a specified frequency of operation. Application of a time domain simulator is illustrated in order to demonstrate start-up performance and limit cycle formation in the presence and absence of a frequency entrainment signal. The issue of stability of the active element is also addressed using a modified device/load line method. Theoretical and experimental results are presented for the external quality factor, locking power/phase variation, and power and frequency pushing characteristics of the active antenna. Finally, the effect on oscillator behavior of the mutual coupling between the microstrip patch and the active antenna distributed embedding elements is discussed.

Journal ArticleDOI
TL;DR: In this article, the authors present algorithms for the design of nonsynchronous non-commensurate transmission-line impedance transformers with the equal ripple insertion loss functions, which can be easily used as new prototype circuits for designing some other microwave devices.
Abstract: The new algorithms for design of nonsynchronous noncommensurate transmission-line impedance transformers are presented. These algorithms make it possible to design the two-, four-, and six-section transformers with the equal ripple insertion loss functions. The transformers designed in this way are significantly shorter in comparison to the corresponding well-known quarter-wave Chebyshev ones (synchronous commensurate). It is also shown that transformers of this type can be easily used as new prototype circuits for designing some other microwave devices. The 3-dB three-port power divider is described as an example of a device designed in this manner.

Journal ArticleDOI
TL;DR: In this paper, a spectral domain approach was adopted to carry out the analysis of the surface current density of the microwave and millimeter-wave integrated circuits (MMICs) for the characterization of arbitrarily shaped discontinuities.
Abstract: A representation of the surface current density particularly suited for the electrodynamic characterization of arbitrarily shaped discontinuities in monolithic microwave and millimeter-wave integrated circuits (MMICs) is presented. The spectral domain approach (SDA) is adopted to carry out the analysis. Some numerical results, obtained using the proposed current representation, are compared with those available in the literature. A fast and excellent numerical convergence for the scattering parameters is achieved.


Journal ArticleDOI
TL;DR: In this paper, the authors examined the advantages and limitations of the FDTD method for CAD of microstrip arrays and compared with experiment for a 3-patch coplanar parasitic patch array.
Abstract: The finite-difference time-domain (FDTD) method is a widely used numerical technique for computer-aided design (CAD) of printed antennas and arrays. This technique can accurately predict performance characteristics of complex microstrip antennas, including the effects of parasitic elements and aperture-coupled feeds. In the case of arrays, mutual coupling effects between closely packed elements can also be modeled. This article will examine the advantages and limitations of the FDTD method for CAD of microstrip arrays. Calculated results are compared with experiment for a 3-patch coplanar parasitic patch array.

Journal ArticleDOI
TL;DR: In this article, a CAD procedure is proposed to reduce the sidelobe level by tapering width and separation of metal strips, and the results of the CAD procedure are compared with theoretical predictions with good agreement.
Abstract: Theoretical and experimental results are presented for a printed leaky-wave antenna. Mode-matching and EDC methods have been used to analyze the antenna and to design the prototypes. Reflection, transmission, and radiation measurements have been compared with theoretical predictions with good agreement. A CAD procedure is proposed to reduce the sidelobe level by tapering width and separation of metal strips.

Journal ArticleDOI
TL;DR: A statistical interpolation technique is presented for modeling S-parameter measurements for use in statistical analysis and design of circuits by interpolating among the measurements in an S- parameter data base in a statistically valid manner.
Abstract: A statistical interpolation technique is presented for modeling S-parameter measurements for use in statistical analysis and design of circuits. This is accomplished by interpolating among the measurements in an S-parameter data base in a statistically valid manner.

Journal ArticleDOI
TL;DR: Various modeling parameters are used to determine the convergence of a GaAs microstrip's simulated transmission line characteristics and it is shown that a designer must use a convergence analysis to prove the validity of an electromagnetic simulation.
Abstract: Full-wave electromagnetic simulators have enabled microwave designers to simulate complex geometries which sometimes cannot be done by conventional computer-aided design (CAD) nodal simulators. However, designers should pay close attention to how the numerical implementation of the full-wave analysis can affect the results of the electromagnetic simulation. This study uses various modeling parameters to determine the convergence of a GaAs microstrip's simulated transmission line characteristics. A commercially available program, Sonnet's “EM,” was used for the analysis but the results can be generalized for any full-wave analysis. This article explores the limits of Sonnet as well as showing that a designer must use a convergence analysis to prove the validity of an electromagnetic simulation. © 1994 John Wiley & Sons. Inc.

Journal ArticleDOI
TL;DR: In this article, the magnetic-wall approximation for their slots, shielded coplanar waveguides (SCPWs) and semienclosed CPWs (SECPWs) are analyzed through an intensive use of elliptic function transformation.
Abstract: On the magnetic-wall approximation for their slots, shielded coplanar waveguides (SCPWs) and semienclosed CPWs (SECPWs) are analyzed through an intensive use of elliptic function transformation. CAD-oriented formulas for the quasi-TEM parameters of SCPWs and SECPWs, including their coupled versions, are derived. The comparison of the results calculated here with previous ones show 2% accuracy for formulas in the practical situation where the slots are not too wide, e.g., s / (s + 2w) ≥ 0.2 for an SCPW. © 1994 John Wiley & Sons, Inc.

Journal ArticleDOI
TL;DR: In this article, a computer code is written to analyze different configurations of finite microstrip arrays, which are made of circular patches with coaxial feeds and exciting different modes, such as mutual coupling between the elements and surface wave effects.
Abstract: A computer code is written to analyze different configurations of finite microstrip arrays. This code will be used as an educational and design tool for students and industrial engineers. The code will be available on PC computers in an interactive graphic mode for the NSF/IEEE Center on Computer Applications in Electromagnetics Education (CAEME). The arrays are made of circular patches with coaxial feeds and exciting different modes. Mutual coupling between the elements and surface wave effects are considered. The conventional dual feed configuration is used to generate circular polarization. Also, circular polarization is realized by sequential feeding of linearly polarized elements. Different array configurations of fixed and scanned beams are analyzed.


Journal ArticleDOI
TL;DR: The dispersion characteristics and interaction impedances of a disk-loaded cylindrical waveguide structure were investigated using theoretical, computer, and experimental techniques.
Abstract: The dispersion characteristics and interaction impedances of a disk-loaded cylindrical waveguide structure were investigated using theoretical, computer, and experimental techniques. Satisfactory agreement has been demonstrated between the experimentally determined values, the results obtained theoretically, and the computer-generated values using the ARGUS and SOS computer codes. © 1994 John Wiley & Sons, Inc.

Journal ArticleDOI
TL;DR: In this paper, a quasi-TEM approach was used to analyze multilayered multiconductor transmission lines with polygonal cross-section-perfect conductors. But the authors focused on the fast and accurate computation of spectral integrals and recurrence formulas to compute the tail integrals.
Abstract: Multilayered multiconductor transmission lines with polygonal cross-section-perfect conductors are analyzed under a quasi-TEM approach. According to a model previously proposed by the authors, each polygonal cross-section conductor is modeled as a set of zero-thickness strips. The substrates can be lossy, and present possible gyromagnetic (longitudinal magnetization) characteristics as well as dielectric anisotropic properties. The method of moments of Galerkin is applied in the spectral domain to analyze the model structure. Special attention has been paid to the fast and accurate computation of spectral integrals. Thus, the possible symmetries of the Galerkin matrix are emphasized and recurrence formulas to compute the tail integrals have been developed. © 1994 John Wiley & Sons, Inc.

Journal ArticleDOI
TL;DR: In this paper, discrete complex image theory (DCIT) without the optimization process is used in the calculation of some Sommerfeld integrals involved in the problem of a microstrip antenna covered with a layer of medium.
Abstract: Discrete complex image theory (DCIT) without the optimization process is used in the calculation of some Sommerfeld integrals (SI) involved in the problem of a microstrip antenna covered with a layer of medium. By comparison to the results of numerical integration method (NIM), it is proved that this DCIT not only has very high efficiency but also has rather satisfying accuracy so long as the proper spatial quasi-static images (SQSI) are found. Special effort is made to the extraction of the above-mentioned SQSI, and the analytic expressions of them are presented for the particular SI discussed here. The computation time of DCIT and that of NIM are compared to each other with microcomputer AFTI486, and the result shows that DCIT is several hundred times faster than NIM in the calculation of SI.

Journal ArticleDOI
TL;DR: A quasi-analytical method for computing the quasi-static-TEM parameters of the generalized coplanar waveguide (GCPW) is reported in this article, where the structure is assumed to be enclosed in a rectangular frame and embedded in a layered medium.
Abstract: A quasi-analytical method for computing the quasi-static-TEM parameters of the generalized coplanar waveguide (GCPW) is reported. The structure is assumed to be enclosed in a rectangular frame and embedded in a layered medium. Essentially, the method is an analytically enhanced spectral domain formulation. Its application leads to virtually exact results in very short CPU times, making it suitable for CAD purposes. Although the method is somewhat more time consuming than conformal mapping approaches, it is a useful alternative because of its exactness and ability to deal with multilayer structures. © 1994 John Wiley & Sons, Inc.

Journal ArticleDOI
TL;DR: In this paper, a software verification effort to verify the accuracy of the simulation program developed by the Center for Microwave/Millimeter-Wave Computer-Aided Design (MIMICAD) is described.
Abstract: A software verification effort to verify the accuracy of the simulation program developed by the Center for Microwave/Millimeter-Wave Computer-Aided Design (MIMICAD) is described. A set of single-layer microstrip structures selected by the MIMICAD sponsors were fabricated on GaAs substrates for testing purposes. Ranging from an interdigitated capacitor to radial stubs to a section of meander line, these test structures are components commonly used in MMIC designs. Round-robin measurements of the test structures were carried out among the MIMICAD sponsors to assess measurement consistency. Comparisons between the measured and simulated results as well as the effect of discretization in the simulation process are discussed.

Journal ArticleDOI
TL;DR: In this article, the optimum choice of bias point, load and drive level for solid-state power amplifiers is performed via a design methodology based on a novel iterative analysis method.
Abstract: Optimum choice of bias point, load and drive level for solid-state power amplifiers is performed via a design methodology based on a novel iterative analysis method The effectiveness of the proposed methodology and the corresponding level of accuracy is demonstrated through a comparison with the results of a more elaborate commercial CAD software and with experimental data, © 1994 John Wiley & Sons, Inc

Journal ArticleDOI
TL;DR: In this paper, an experimental optimization of the noise figure of small-signal self-aligned FETs is presented, which shows a ∼0.7dB improvement in noise measure without requiring major process changes.
Abstract: This article presents an experimental optimization of the noise figure of small-signal self-aligned FETs. An L18 orthogonal array has been used to find the main effects of specific device parameters on noise performance at 18 GHz. This knowledge has been used to find an alternative device which shows a ∼0.7-dB improvement in noise measure without requiring major process changes. Hybrid low-noise amplifiers built with the improved FETs confirm the noise performance and show record power performance for high dynamic range applications. © 1994 John Wiley & Sons, Inc.

Journal ArticleDOI
TL;DR: A rigorous filter design using the finite element method and an optimization process is described to show the validity of this method, here applied to a millimeter-wavelength metal insert filter.
Abstract: A rigorous filter design using the finite element method and an optimization process is described. To show the validity of this method, it is here applied to a millimeter-wavelength metal insert filter. The influence of higher order mode interactions and of metallic losses is also described. © 1994 John Wiley & Sons, Inc.