By Topic

Microwave Theory and Techniques, IEEE Transactions on

Issue 1 • Date Jan 1988

Filter Results

Displaying Results 1 - 25 of 27
  • Complex modes in lossless shielded microstrip lines

    Page(s): 163 - 165
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (120 KB)  

    The possible existence of complex modes in lossless shielded microstrip lines was investigated using the singular integral equation method. The method is used for the analysis of three lossless shielded microstrip line structures with different substrate permittivities. To confirm the validity of the method, results are compared with existing data for propagating modes. Complex modes were found in the moderate and high permittivity structures. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Comments, on "Comparison of the FFT conjugate gradient method and the finite-difference time domain method for the 2-D absorption problem" [with reply]

    Page(s): 166 - 170
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (638 KB)  

    For the original article see ibid., vol.MTT-35, no.4, p.383-95 (1987). In commenting on the above named work by D.T. Borup et al. it is asserted that certain wrong assumptions about the FFT (fast Fourier transform) conjugate gradient method lead to meaningless statements in the original work. In a reply from two of the three original authors is it made clear that (1) several conclusions attributed to the original work do not appear in the work; and (2) an algorithm claimed in the comment to be the solution of an operator equation, as opposed to a matrix equation, is actually equivalent to a matrix moment solution.<> View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Comments on "A method for measurement of losses in the noise-matching microwave network while measuring transistor noise parameters" [with reply]

    Page(s): 170 - 172
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (331 KB)  

    For the original article see ibid., vol.MTT-35, no.1, p.71-5 (1987). The commenter points out that equations (1), (2), and (3) of the above named work are true only if the tuner's physical temperature is 290 K. It is noted that the derivation of other equations is needlessly complicated. In replying, the authors show that any error arising from this assumption is negligible. In rebutting the reply, the commenter notes that in some cases, the errors introduced by the assumption are not negligible.<> View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Optimization of helical coil applicators for hyperthermia

    Page(s): 148 - 150
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (284 KB)  

    Numerical solutions were used to optimize helical coil applicators to maximize the ratio of axial heating to surface heating within coaxial muscle cylinders. It is shown that this optimization requires significantly larger values of pitch angle and frequency than any previously specified for experimental applicators. The maximum ratio of axial to surface heating is obtained with a linear helix defined to have a pitch angle of 90°. Calculated ratios of axial/surface heating with a linear helix are as large as 2.54 (at 352 MHz) for a muscle cylinder with a radius of 4 cm, and 1.26 (at 82 MHz) for one with a radius of 8 cm. The relationship of the linear helix applicator to the annual phased-array applicator and to the resonant cylindrical cavity applicator is discussed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Nonlinear optimization of the shape function in the finite element method when determining cutoff frequencies of waveguides of arbitrary cross section

    Page(s): 151 - 152
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (176 KB)  

    The authors studied the k optimization process of the finite-element method when solving eigenvalue problems. The optimization process is then applied to the determination of the fundamental cutoff frequency of a waveguide of cardiodal cross section. It is shown that a considerable reduction in computer memory and/or CPU time is achieved by this process View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Power deposition of a microstrip applicator radiating into a layered biological structure

    Page(s): 126 - 131
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (464 KB)  

    The power deposited by a microstrip antenna into a layered biological structure is presented. The solution is based on an integral equation for the surface current density on the antenna and on an electric Green's dyadic for the fields inside a planar stratified medium. The integral equation is solved using the method of moments in conjunction with the point-matching technique. The modeling of the surface current takes the edge conditions into account. Special attention is devoted to a correct modeling of the excitation of the antenna by a coaxial feed. The numerical results focus on the power deposition as a function of depth View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Propagation losses in dielectric image guides

    Page(s): 155 - 158
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (340 KB)  

    The authors calculated the propagation losses of a dielectric image guide using the effective dielectric constant (EDC) method to a higher order of approximation. It was found that there exist a minimum in the waveguide attenuation that has not been alluded to in the literature, and also a peak in the imaginary parts of the transverse propagation constant relate to dimensional resonances within the waveguide. These results imply that the propagation losses will be lowered and the fields will be more effectively confined within the waveguide at frequencies close to the cutoff View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Insertion loss of magnetostatic surface wave delay lines

    Page(s): 132 - 136
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (376 KB)  

    An experimental and theoretical study is presented of the insertion loss of magnetostatic surface wave delay lines. The magnetostatic surface waves are excited by single microstrip transducer and propagate in a delay line consisting of conductor-dielectric-YIG-GGG. The effect of nonuniformity in microstrip current and the effect of finite width of YIG film are included in the theory. An undesired notch seen in the insertion-loss response of the surface-wave delay line in the low-frequency region of the band is explained by the present theory, which includes the finite width of the YIG film View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A 4.5-GHz GaAs dual-modulus prescalar IC

    Page(s): 158 - 160
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (268 KB)  

    A description is given of a 4.5-GHz divide-by-256/258 dual-modulus prescalar with a reset function. The prescalar operates at a supply voltage of 3 V with a power dissipation of 100 mW. A low-power, source-coupled FET logic (LSCFL) using novel level-shift circuits and 0.5-μm-gate buried p-layer SAINT FETs were used to achieve this performance View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Quasi-optical integrated antenna and receiver front end

    Page(s): 80 - 85
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1036 KB)  

    A quasioptical receiver front end applicable to both microwave and millimeter-wave receiver arrays is presented. Two planar microwave integrated circuit (MIC) quasioptical receiver circuit designs that integrate a coupled slot antenna, a Schottky-diode balanced mixer, and a local oscillator on the same substrate are described. The even-mode/odd-mode characteristics of the coupled slotlines are used to achieve intrinsic RF/LO and RF/IF isolation. To demonstrate circuit feasibility, X-band scaled models of the circuit unit using a Gunn-diode oscillator on an Epsilam-10 substrate, and MESFET local oscillator on a R/T Duroid substrate were built and tested. Results of these tests are included View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Analysis of MMIC structures using an efficient iterative approach

    Page(s): 96 - 105
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (824 KB)  

    A class of two-dimensional and three-dimensional monolithic microwave integrated circuit (MMIC) structures is analyzed theoretically using an efficient iterative technique. The transfer-matrix approach to constructing the spectral Green's functions of multilayered structures is adopted. Discretization of the continuous functions and utilization of the periodicity of the MMIC structures enclosed by sidewalls lead to a discrete convolution operation, which is carried out efficiently using the FET (fast Fourier transform) algorithm. The spectral Green's functions are modified for both the periodic and aperiodic structures to improve the numerical efficiency of the iterative algorithm. Numerical results are presented and compared with available data View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Galerkin solution for the thin circular iris in a TE11-mode circular waveguide

    Page(s): 106 - 113
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (552 KB)  

    An integral equation for the transverse electric (TE) field in the aperture of a concentric circular iris in a transverse plane of a circular waveguide is approximately solved using Galerkin's method. The aperture field is represented by a finite sum of normal TE and TM (transverse magnetic) circular waveguide modes that fit the circular aperture. The numerical convergence of the Galerkin solution is demonstrated using the resultant aperture field distributions and equivalent shunt susceptance for the case of dominant TE11-mode excitation. The resultant aperture electric field distribution closely resembles that of the TE11 aperture mode alone, except for edge contribution behavior at the edge of the iris. A resonant or capacitive iris is possible over a restricted range of frequencies View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Scattering by a lossy dielectric cylinder in a rectangular waveguide

    Page(s): 137 - 144
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (492 KB)  

    Electromagnetic fields in a rectangular waveguide containing a lossy dielectric cylinder are investigated by means of the orthogonal expansion method. The calculated results are provided by measurement. Resonance effects become visible through the frequency responses of the scattering parameters and understandable by patterns due to magnetic fields and Poynting vectors. The lowest resonance is nonsymmetric and can be used to realize tunable bandstop filters with a relative 3-dB bandwidth of about 0.04 and an attenuation of more than 40 dB View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A fully analytical AC large-signal model of the GaAs MESFET for nonlinear network analysis and design

    Page(s): 61 - 67
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (420 KB)  

    A fully analytical version of an AC large-signal model for the GaAs MESFET is presented. The source model is based on basic principles and the actual physics and geometry of the device. The analytical version was developed by curve fitting the analytical expressions to the source model. The accuracy of the model for microwave circuits is demonstrated using simulation examples of a power amplifier and a mixer View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Electromagnetic coupling between two half-space regions separated by two slot-perforated parallel conducting screens

    Page(s): 44 - 52
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (588 KB)  

    The problem of electromagnetic coupling between two half-space regions separated by two slot-perforated parallel conducting planes is investigated. A general moment solution for the problem is obtained. This moment solution is then specialized to the case of narrow slots and to a TE (transverse electric to the slot axis) excitation. Attention is given to the power transmitted from one half-space to the other through the slots and to its functional dependence on various problem parameters involved View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • GaAs on Si as a substrate for microwave and millimeter-wave monolithic integration

    Page(s): 160 - 162
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (232 KB)  

    The authors calculated the effective dielectric constant, characteristic impedance, and dielectric loss of a shielded microstrip line manufacture on namely GaAs, Si, and GaAs/Si. Dielectronic loss versus frequency for the GaAs and Si substrates are shown. The same parameters for GaAs/Si substrate were plotted for two different resistivities of the GaAs overlay material, and for each of three different GaAs overlayer thicknesses. The measurements covered the 10-100-GHz frequency range. Depending on the thickness, results show that high-resistivity GaAs epitaxial layers on Si substrates having moderate resistivities reduce the dielectric loss View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Characterization of via connections in silicon circuit boards

    Page(s): 21 - 27
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (524 KB)  

    Conducting vias, isolated by silicon dioxide from a bulk silicon wafer and used to interconnect stripline transmission lines on opposite surfaces of the wafer, are analyzed. The net VSWR (virtual standing wave ratio) and insertion loss for a single via and the crosstalk or coupling between two nearby vias are determined as a function of geometry, frequency, and silicon resistivity. For small via dimensions and frequencies up to 1 GHz, the analysis predicts low VSWR and low insertion loss, provided the silicon resistivity is greater than about 100 Ω-cm. It is shown that crosstalk can be small, and is mostly due to inductive coupling View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A method for evaluating the noise temperature of microwave thermal noise sources by introducing an auxiliary transmission line

    Page(s): 145 - 147
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (224 KB)  

    A method is proposed to evaluate the noise temperature of a microwave thermal noise source. The noise temperature correction factor due to the transmission line between the termination and the output is expressed in terms of directly measurable parameters. The correction factor is determined by introducing an auxiliary transmission line composed to two lines connected back-to-back, each of which is identical to that of the unknown source View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Transient analysis of ferrite in three-dimensional space

    Page(s): 114 - 125
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (744 KB)  

    The authors present Bergeron's formulation of vector analysis for magnetized ferrite in a three-dimensional space and time domain. Results are provided for two cases with respect to the relative angle between the directions of the DC magnetic field and wave propagation. For both cases, the results are compared with analytical ones, and the validity of the formulation is verified View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Finite curvature and corrugations in dielectric ridge waveguides

    Page(s): 68 - 79
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (784 KB)  

    The authors present a technique based on the concept of local modes that is capable of handling finite, tight bends in open dielectric waveguides of the LSE-mode or LSM-mode type, together with step discontinuities along the arc. By analytical manipulation of the continuum, the approach results in a small system of coupled integrodifferential equations, one for each discrete propagating mode. The latter system is solved analytically by means of an iterative approach to the point where it can be implemented on a desktop computer. The method was applied to the curved, corrugated, dielectric ridge waveguide, yielding numerical results in general agreement with published experimental points. The technique is equally applicable to other curved open transmission media in the microwave, millimetric, and integrated optics ranges View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Transient analysis of microstrip line on anisotropic substrate in three-dimensional space

    Page(s): 34 - 43
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (896 KB)  

    The authors describe how anisotropy, with the permittivity tensor involving off-diagonal elements, may be generally formulated by Bergeron's method. The formulation is discussed for the propagation characteristics of single and parallel striplines on a sapphire substrate with tilted optical axis. To show the distinctive influence of anisotropy on the coupling property between lines, a parallel-line-type directional coupler on such a substrate is analyzed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Noise modeling and measurement techniques [HEMTs]

    Page(s): 1 - 10
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (800 KB)  

    The high electron mobility transistor's (HEMT's) noise behavior is presented from theoretical and experimental points of view. The general method used in the high-frequency noise analysis is described and the different approximations commonly used in the derivation of the noise parameter expressions are discussed. A comparison between the noise performance of both MESFETs and HEMTs is carried out. The measurement techniques providing the noise figure and the other noise parameters are then described and compared View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Mutual impedance between probes in a waveguide

    Page(s): 53 - 60
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (408 KB)  

    The general formulas for mutual impedance between two probes arbitrarily located in a rectangular waveguide are given by means of dyadic Green's function (DGF), field transformation, and reaction concept. In the formulation presented, the waveguide is semi-infinite. Lengths, feeding points, and orientations of the two probes in the waveguide are all arbitrary. As examples, expressions of mutual impedance for eight specific cases are given and discussed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Noise in two-tier matrix amplifiers

    Page(s): 11 - 20
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (692 KB)  

    A noise theory for the two-tier matrix amplifier is developed that permits the computation of the amplifier's noise figure as a function of the active device and circuit parameters. The computed results based on the noise parameters of a GaAs MESFET with gate dimensions 0.25 μm×200 μm are discussed. In addition, a comparative study is done on the performance data from a 2×4 matrix amplifier and its equivalent two-stage distributed amplifier. Finally, the noise characteristics of two 2×4 matrix amplifiers incorporating GaAs MESFETs processed on either ion-implanted or VPE (vapor-phase epitaxial) substrate material are compared with those measured on actual amplifiers View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • SPICE implementation of lossy transmission line and Schottky diode models

    Page(s): 153 - 155
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (240 KB)  

    The author describes models for the lossy transmission line and the Schottky diode that are incorporated into the source code of the circuit simulation program SPICE (version 2G.6). The model used for the lossy transmission line was derived by A.J. Gruodis (1979). The DC model for the Schottky barrier diode as shown was formulated by D.B. Estreich (1983). Examples used to verify the models are given View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

Aims & Scope

The IEEE Transactions on Microwave Theory and Techniques focuses on that part of engineering and theory associated with microwave/millimeter-wave components, devices, circuits, and systems involving the generation, modulation, demodulation, control, transmission, and detection of microwave signals. This includes scientific, technical, and industrial, activities. Microwave theory and techniques relates to electromagnetic waves usually in the frequency region between a few MHz and a THz; other spectral regions and wave types are included within the scope of the Society whenever basic microwave theory and techniques can yield useful results. Generally, this occurs in the theory of wave propagation in structures with dimensions comparable to a wavelength, and in the related techniques for analysis and design..

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Dominique Schreurs
Dominique.Schreurs@ieee.org

Editor-in-Chief
Jenshan Lin
jenshan@ieee.org