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Microwave Theory and Techniques, IEEE Transactions on

Issue 7 • Date July 1998

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Displaying Results 1 - 25 of 26
  • Discussion on spikes and plateaus in pulse distortion shape along exponential microstrip taper

    Page(s): 1013 - 1015
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (172 KB)  

    The propagation distortions of a nonideal square pulse along an exponential microstrip taper have been numerically calculated. Each part of the distorted pulse shape is related to either the frequency-dependent characteristics of the effective relative permittivity or to the frequency-dependent reflection coefficient characteristics. The components of signal spectra at frequencies below 9 Grad/s do not cause the ringing distortions, but cause the upward slope shift in the center part and the upward parallel shift in the sustained tail part to the distorted pulse shape for the case of no reflection (NR). The ringing distortions and the large spikes of the overshoot and undershoot distortions are caused by the components of the signal spectra in the frequency range 100/spl les//spl omega//spl les/200 Grad/s where the effective relative permittivity is changing very quickly with frequency. View full abstract»

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  • A sub-nanosecond resonant-type monolithic T/R switch for millimeter-wave systems applications

    Page(s): 1016 - 1019
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    This paper is concerned with the design consideration, fabrication process, and performance of a V-band monolithic transmit/receive (T/R) switch for millimeter-wave wireless networks applications. The developed switch integrated circuit (IC) has a novel structure in which to pass a signal, it presents a parallel resonant circuit to the signal by forward biasing a pair of switching heterojunction FET's (HJFETs), but to block the signal, it presents a series resonant circuit to the signal by reverse biasing the switching HJFETs. With a control voltage of 0/3.2 V, the developed T/R switch exhibits a minimum insertion loss of 3.9 dB, a maximum isolation of 41 dB, and a high switching speed of 250 ps, over 57-61 GHz. The monolithic T/R switch chip size is 3.3 mm×1.7 mm View full abstract»

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  • Physical scaling rules for AlGaAs/GaAs power HBTs based on a small-signal equivalent circuit

    Page(s): 1006 - 1009
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    Physical scaling rules for AlGaAs/GaAs heterojunction bipolar transistors (HBTs) containing 2-16 emitter fingers are demonstrated, the parameter extraction is based on a small signal equivalent circuit. The scaling parameters compare favorably with the measured data from the process control monitor View full abstract»

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  • Millimeter-wave beams with phase singularities

    Page(s): 948 - 951
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    Beams of millimeter-wave radiation carrying phase singularities have been generated using specially configured plane and blazed gratings. The blazed grating converts a plane wave into such a beam with very high efficiency. All of the properties of these beams that have been seen at optical wavelengths, such as the hollow profiles of the beams and the way a beam already carrying a singularity is subsequently diffracted, are shown to appear at millimeter wavelengths View full abstract»

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  • FDTD treatment of partially magnetized ferrites with a new permeability tensor model

    Page(s): 983 - 987
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    This paper outlines the finite-difference time-domain (FDTD) treatment of partially magnetized ferrites characterized by a permeability tensor model, which was recently published. Its causal aspect makes this tensor well adapted to time-domain simulations. Validation is demonstrated for a resonant ferrite structure, Numerical and analytical results are compared, showing good agreement View full abstract»

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  • Scattering at a nonchiral-chiral interface in a coaxial waveguide

    Page(s): 997 - 1001
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    A formally exact full-wave solution is presented for the problem of scattering at a nonchiral-chiral interface in a coaxial waveguide. The field components for the axisymmetric modes in a coaxial chirowaveguide are initially obtained. A new orthogonality relation for the modes is then proposed and used to find expansion coefficients for the electromagnetic fields in the coaxial chirowaveguide. The scattering matrix for the nonchiral-chiral dielectric discontinuity in a coaxial waveguide is finally derived by enforcing the continuity conditions of the tangential field components across the interface. Numerical results for the reflection and transmission coefficients at the nonchiral-chiral interface in a coaxial waveguide are presented View full abstract»

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  • Monolithic packaging concepts for high isolation in circuits and antennas

    Page(s): 900 - 906
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    High-frequency planar circuits experience large electromagnetic (EM) coupling in dense circuit environments. As a result, individual components exhibit performance degradation that ultimately limits overall circuit response. This paper addresses crosstalk in planar microstrip lines by evaluating micromachined packages as a means to reduce coupling. Microstrip lines with straight and meandering paths can exhibit crosstalk coupling as high as -20 dB (i.e., when placed in a side-by-side arrangement). From our study, inclusion of a monolithic package reduces this effect by as much as: -30 dB and, consequently, offers the requisite electrical and environmental protection in addition to shielding of individual elements from parasitic radiation. Presented herein is the development of the micromachined package for microstrip geometries. Included in the discussion are crosstalk effects between straight and bending geometries in open and packaged configurations and an evaluation of package noise characteristics. A packaged antenna element is also included as a demonstration of the potential use of micromachined packaging in array applications View full abstract»

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  • Using selective asymptotics to accelerate dispersion analysis of microstrip lines

    Page(s): 1024 - 1027
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    A selective asymptotic technique (SAT) to accelerate the elements of the impedance matrix in the conventional spectral-domain approach (SDA) is presented. Instead of using the full asymptotic expression of the Green's functions, only those parts which cannot be evaluated in closed form are approximated by their asymptotic expressions. The resulting expressions are more accurate and systematic, as no additional parameter is introduced. The technique is applied to determine the effective dielectric constant of an open microstrip line to demonstrate its efficiency View full abstract»

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  • Performance of MODFET and MESFET, a comparative study including equivalent circuits using combined electromagnetic and solid-state simulator

    Page(s): 923 - 931
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (248 KB)  

    A combined electromagnetic and solid-state (CESS) simulation model for the analysis of submicrometer semiconductor devices including the electromagnetic-wave propagation effects is presented. The performance comparison of two important high-frequency devices-modulation doped field-effect transistor (MODFET) and metal-semiconductor field-effect transistor (MESFET)-are illustrated using this model. The CESS simulator couples a semiconductor model to the three-dimensional (3-D) time-domain solution of Maxwell's equations. The semiconductor model is based on the moments of the Boltzmann's transport equation. The simulation uses the electromagnetic-wave concept to emphasize the better performance of MODFET over MESFET. The electromagnetic-wave propagation effects on the two devices are thoroughly analyzed. The use of the electromagnetic model over the conventional quasi-static model provides the actual device response along the gatewidth at high frequencies. The exchange of energy between the electrons and the electromagnetic wave is observed. The CESS model also facilitates the optimum choice of the device width in terms of the output voltage. This model is capable of predicting the large-signal behaviour of the submicrometer devices as well. The equivalent-circuit parameters are extracted at high frequencies for MODFET and MESFET, using a time-domain approach as well as a quasi-static approach View full abstract»

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  • Circuit model for coupling between MMICs in multichip modules including resonance effects

    Page(s): 959 - 965
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (244 KB)  

    This paper describes a circuit model to be used for the approximate calculation of coupling between monolithic microwave integrated circuits (MMICs) in a multichip module. The model is developed from basic electromagnetic principles and relies on the formation of equivalent electric dipoles to represent the complex currents on the various MMICs within the module. The technique is suitable for use in layout-based circuit simulators and uses no numerical analysis View full abstract»

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  • Calibration and verification of the pure-mode vector network analyzer

    Page(s): 1009 - 1012
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (96 KB)  

    In this paper, the calibration of a pure-mode vector network analyzer (PMVNA) is presented in detail. The analyzer is intended for the measurement of mixed-mode scattering parameters (s-parameters) of differential circuits, but is also suitable for measurement of general microwave networks with up to four ports. The theory of calibration of the analyzer is developed in terms of a general n-port analyzer, including the correction of port-to-port crosstalk. The type of the standards used in calibration is examined, and the minimum number of standards are summarized for various levels of crosstalk correction. A new standard for all multiport network analyzer calibrations is introduced. A calibration is performed from 0.25 to 25.25 GHz based on standards with coaxial connectors, and verification standards are measured. The measured data is compared with National Institute of Standards and Technology (NIST) traceable measurements, and errors are found to be generally less than ±1 dB in transmission. In many cases, the error is less than the uncertainty of the NIST traceable measurements View full abstract»

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  • Reflection-type low-phase-shift attenuator

    Page(s): 1019 - 1021
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (112 KB)  

    A transmission-type phase-shift attenuator has a poor reflection characteristic at an output port. In this paper, to avoid such disadvantages, a reflection type low phase-shift attenuator has been designed and measured. As a result, at a center frequency (1855 MHz), the reflection-type low-phase-shift attenuator has an attenuation of 30 dB, within the limit of 3° phase shift and less than -17-dB reflection characteristics at both input and output ports. It also demonstrates that the performance of the reflection type low-phase shift attenuator is better than the transmission type phase-shift attenuator with the same measurement specifications View full abstract»

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  • Transfer matrix function (TMF) for wave propagation in dielectric waveguides with arbitrary transverse profiles

    Page(s): 975 - 982
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (448 KB)  

    A transfer matrix function (TMF) is derived for the analysis of electromagnetic (EM) wave propagation in dielectric waveguides with arbitrary profiles, situated inside rectangular metal tubes. The TMF relates the wave profile at the waveguide output to the (arbitrary profile) input wave in the Laplace space. The TMF consists of the Fourier coefficients of the transverse dielectric profile and those of the input-wave profile. The method is applicable for inhomogeneous dielectric profiles with single or multiple maxima in the transverse plane. The TMF is useful for the analysis of dielectric waveguides in the microwave and the millimeter-wave regimes and for diffused optical waveguides in integrated optics View full abstract»

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  • A Galerkin moment method for the analysis of an insulated antenna in a dissipative dielectric medium

    Page(s): 988 - 996
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (316 KB)  

    A Galerkin moment method is employed to solve the problem of a dielectric-coated dipole antenna in a dissipative medium. Piecewise sinusoids are used as basis and testing functions. The dielectric coating is modeled by equivalent-volume polarization currents, which are simply related to the conduction current distribution. No additional unknowns are introduced, and the size of the moment-method matrix is the same as that for bare antennas. Exact and approximate formulas for the near electric field are derived. The computed results exhibit excellent agreement with those previously published for a symmetric, as well as an asymmetric insulated dipole. Compared to its existing competitors, the new method appears to be more general and computationally efficient View full abstract»

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  • Analysis of an experimental technique for determining Van der Pol parameters of a transistor oscillator

    Page(s): 914 - 922
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    The Van der Pol (VDP) model of a transistor oscillator describes the behaviour of the oscillator with three parameters. When operating in steady state, only two parameters can be determined by spectrum analysis, these being the oscillation frequency and amplitude of oscillation. In this paper, a technique for measuring the other VDP parameter is examined. In this approach, a periodically modulated voltage is added to the bias of the oscillator to perturb the operational state. A theoretical derivation shows that the power spectrum of the perturbed oscillator contains additional information for determination of the other VDP parameter. A simple analytical perturbation formula predicts the oscillator's response to the ramped bias. Our experimental results agree with the analytical perturbation solution and therefore, this allows one to read off the other VDP parameter from the experimental data. The VDP model allows one to predict the behaviour of coupled transistor oscillators more accurately and simply than does the traditional large-signal model of the transistor. This VDP model will simplify oscillator array design since the number of parameters needed to describe each oscillator is reduced from that which would be required using a large-signal circuit model View full abstract»

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  • Analysis of mode coupling on guided-wave structures using Morse critical points

    Page(s): 966 - 974
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    New insight on mode coupling in waveguiding structures is obtained from the theory of Morse critical points (MCP's). It is shown that the traditional coupled-mode formalism has a clear analytical connection with functional properties of the characteristic determinant in the vicinity of the Morse critical point, which determines the minimum of coupling. The relationship between perturbed and independent modes in the mode-coupling region is obtained using the Taylor polynomial of order two about the Morse critical point, and it is found that the coupling factor is proportionally related to the value of a characteristic function at this point. The qualitative modal behaviour in the mode-interaction region is predicted by a simple normal form, which can be geometrically interpreted as a result of the intersection of a saddle surface and a plane corresponding to the minimum of the coupling factor. Numerical results for a variety of guided-wave structures, including printed-circuit transmission lines, planar-slab waveguides, and shielded microstrip-like lines demonstrate the efficiency of the proposed approach for the rapid identification of mode-coupling regions, and for reconstruction of dispersion behaviour in those regions via simple analytic (normal) forms View full abstract»

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  • Analysis of high-speed interconnects in the presence of electromagnetic interference

    Page(s): 940 - 947
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (240 KB)  

    This paper describes an efficient algorithm based on moment-matching techniques for simulation of high-speed circuits in the presence of electromagnetic interference (EMI). The proposed method is based on the recently developed complex frequency hopping (CFH) technique for interconnect analysis. The new technique is useful for susceptibility analysis and is two to three orders of magnitude faster than conventional simulation techniques. In addition, it can be extended to the analysis of interconnects with frequency-dependent parameters and nonlinear terminations View full abstract»

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  • An integrated Doppler-radar transceiver front end using two FET active antennas

    Page(s): 1001 - 1003
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (96 KB)  

    An integrated X-band Doppler-radar transceiver front end has been developed. This front end consists of two adjacently spaced field-effect transistor (FET) active antennas, with one of them being biased to oscillate as its transmitter and the other being biased not to oscillate, but to act as its mixer. This design has the advantage of lower noise at low Doppler frequencies as compared to a self-oscillating mixer scheme. The circuit can be used in low-power Doppler-radar systems to detect slow-moving objects such as pedestrians, intruders, automobiles, etc., with high sensitivity View full abstract»

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  • Miniature electric near-field probes for measuring 3-D fields in planar microwave circuits

    Page(s): 907 - 913
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB)  

    Three-dimensional (3-D) electric near-field probes applicable to the 0.05-20-GHz band have been developed, which can measure both the magnitude and the phase of the microwave field inside radio-frequency (RF) and microwave circuits. The field probes have very small dimensions and do not need to be connected to the operating device-under-test (DUT), therefore, the circuit properties are nearly not disturbed by the probe, Investigations on different circuits (e.g., antenna, meander lines, filters, and power amplifiers) show that such near-field probes can be applied not only to simple passive circuits, but also to measure the fields inside complex active circuits. These simple, stable, and cheap field probes are very useful for assisting the design of microwave circuits, antenna diagnostics, and testing products in industry View full abstract»

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  • On the use of linear-prediction techniques to improve the computational efficiency of the FDTD method for the analysis of resonant structures

    Page(s): 1027 - 1032
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (188 KB)  

    Linear-prediction (LP) techniques are used to accurately and efficiently compute the frequencies and damping factors of microwave resonant structures from their transient response, which was previously obtained by using the finite-difference time-domain (FDTD) method. The LP equations are formulated in terms of a total least squares (TLS) problem and are solved by using the singular-value decomposition (SVD) algorithm. This approach confers robustness to the LP method, improves the spectral resolution, and provides a simple criterion for selecting the order of the LP model. We illustrate these characteristics of the LP method by applying it to two types of problems: the determination of the propagation constants of waveguides loaded with lossy dielectrics, and the calculation of the resonant frequencies of cylindrical cavities loaded with dielectric ring resonators View full abstract»

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  • Novel compact elliptic-function narrow-band bandpass filters using microstrip open-loop resonators with coupled and crossing lines

    Page(s): 952 - 958
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    Novel compact elliptic-function narrow-band bandpass filters have been designed and fabricated. This new configuration consists of two identical microstrip open-loop resonators with coupled and crossing lines. A theoretical investigation has confirmed that this novel configuration is capable of providing elliptic-function filtering. Furthermore, the feasibility of this filter is verified experimentally. Centered at 2.039 GHz, the fabricated microstrip bandpass filter shows a measured 3-dB bandwidth of 2% and two deep notches in its stopband. In addition, the main circuit of this filter occupies only 2.5 cm×1.5 cm using a substrate with dielectric constant of 10.5, making it very attractive for applications in the mobile and personal communication systems (PCS's) View full abstract»

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  • 60-GHz monolithic down- and up-converters utilizing a source-injection concept

    Page(s): 1003 - 1006
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (96 KB)  

    This paper deals with the design considerations, fabrication process, and performance of coplanar waveguide (CPW) heterojunction FET (HJFET) down- and up-converter monolithic microwave integrated circuits (MMIC's) for V-band wireless system applications. To realize a mixer featuring a simple structure with inherently isolated ports, and yet permitting independent port matching and low local oscillator (LO) power operation, a “source-injection” concept is utilized by treating the HJFET as a three-port device in which the LO signal is injected through the source terminal, the RF (or IF) signal through the gate terminal, and the IF (or RF) signal is extracted from the drain terminal. The down-converter chip incorporates an image-rejection filter and a source-injection mixer. The up-converter chip incorporates a source-injection mixer and an output RF filter. With an LO power and frequency of 7 dBm and 60.4 GHz, both converters can operate at any IF frequency within 0.5-2 GHz, with a corresponding conversion gain within -7 to -12 dB, primarily dominated by the related filter's insertion loss. Chip size is 3.3 mm×2 mm for the down-converter, and 3.5 mm×1.8 mm for the up-converter View full abstract»

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  • An efficient energetic variational principle for modeling one-port lossy gyrotropic YIG straight-edge resonators

    Page(s): 932 - 939
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    This paper presents a new variational principle for the design of one-port gyrotropic magnetostatic-wave (MSW) resonators. We first prove the stationary character of the magnetic energy in the case of a resonator containing lossy gyrotropic media and supporting microwave MSW's. We then show that the variational expression may be successfully used for calculating the input reflection coefficient of a planar multilayered MSW straight-edge resonator (SER). Results obtained using the variational formulation are validated by experiment carried out at X-band. Hence, the resulting model is an efficient tool for designing low-noise wide-band yttrium-iron-garnet (YIG) tuned oscillators View full abstract»

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  • Wave penetration through slits on stacked thick plates

    Page(s): 889 - 893
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    Wave penetration through slits on single and stacked metal plates of finite thickness is studied by using the Galerkin method. The limiting case of slits on infinitesimally thin plates are also formulated to compare the shielding effectiveness of metal plates with slits against incident plane waves. It is observed that the wave penetrating through slits on stacked plates with a proper separation is much less than that through a single slit on a plate with twice the thickness View full abstract»

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  • SLIM: a slender technique for unbounded-field problems

    Page(s): 1022 - 1024
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (72 KB)  

    Electrostatic- and electromagnetic-field problems in unbounded regions are often solved using finite differences (FD's) or finite elements (FE) combined with approximate boundary conditions. Inversion of the sparse FD or FE matrix is then required. First-order or higher order absorbing boundary conditions may be used, or one can use more accurate boundary conditions obtained by the measured equation of invariance (MEI) or by iteration. The more accurate boundary conditions are helpful because they permit reduction of the size of the mesh and, thus, the number of unknowns. In this paper, we show that the process can be carried to a maximally simple limit in which the mesh is reduced to a single layer and the matrix-inversion step disappears entirely. This results in the single-layer iterative method (SLIM), an unusually simple technique for unbounded-field problems. Computational experiments demonstrate the effectiveness of SLIM in electrostatics, and also in electrodynamic examples, such as scattering of TM plane waves from a perfectly conducting cylinder. The technique is most likely to be useful in large or complex problems where simplification is helpful, or in repetitive calculations such as scattering of radiation from many angles of incidence View full abstract»

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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..

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