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Microwave Theory and Techniques, IEEE Transactions on

Issue 5  Part 1 • Date May 1997

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Displaying Results 1 - 23 of 23
  • Correction to "Constraints To The Optimum Performance And Bandwidth Limitations Of Diplexers Employing Three-port Junctions"

    Publication Year: 1997 , Page(s): 704
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  • Correction to "The Relationship Between Dual Mode Cavity Cross-coupling And Waveguide Polarizers"

    Publication Year: 1997 , Page(s): 704 - 705
    Cited by:  Papers (2)
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  • Correction to "Input Impedance Of A Coaxial Probe Located Inside A Rectangular Cavity: Theory And Experiment"

    Publication Year: 1997 , Page(s): 705
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  • Optimum noise measure configurations for transistor negative resistance amplifiers

    Publication Year: 1997 , Page(s): 580 - 586
    Cited by:  Papers (8)
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    A new method, using the noise matrix approach, has been developed for determining the optimum reactive terminations for a transistor employed as a low-noise negative-resistance element in a reflection-mode amplifier. This new method corroborates the less efficient graphical method the authors reported earlier. It is established theoretically and demonstrated numerically that the optimum noise measure of a transistor used in a reflection-mode amplifier is independent of the choice of active terminal and is identical to the optimum noise measure of the same transistor when used in a conventional transmission-mode amplifier View full abstract»

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  • Explicit expressions of the reflection and transmission for two coupled identical exponential lines

    Publication Year: 1997 , Page(s): 695 - 698
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    The reflection and transmission problem of two coupled identical exponential lines is considered in this paper. The exact and explicit expressions for the co- and cross-line reflection and transmission coefficients are derived. The explicit expressions are validated by an independent numerical solution View full abstract»

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  • Operation of new type field displacement isolator in ridged waveguide

    Publication Year: 1997 , Page(s): 698 - 700
    Cited by:  Papers (3)
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    A new type ridged-waveguide field-displacement isolator is analyzed in this paper. Experimental result have been obtained for the isolation, insert loss, and voltage standing wave ratio (VSWR) in C- and X-band. The isolation and bandwidth are found to increase obviously View full abstract»

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  • Sub-cellular technique for finite-difference time-domain method

    Publication Year: 1997 , Page(s): 673 - 677
    Cited by:  Papers (12)
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    The most frequently encountered problem with the finite-difference time-domain (FDTD) method, for the analysis of microstrip line and many other structures, is that the structure generally has important structural features that are very small as compared to the main body in at least one dimension. Thus, to accurately analyze such structures, very small mesh is considered which makes the analysis very expensive, time consuming, and sometimes even impossible due to the computer limitations. In this paper, a new sub-cellular technique has been proposed which takes care of such problems as well as many other problems, such as curved surfaces (in which interfaces are not parallel to one of the coordinate planes and stair-step approximation is considered) View full abstract»

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  • Fixed-tuned submillimeter wavelength waveguide mixers using planar Schottky-barrier diodes

    Publication Year: 1997 , Page(s): 653 - 658
    Cited by:  Papers (36)
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    The design, construction, and evaluation of fixed-tuned submillimeter wavelength waveguide mixers using planar Schottky diodes are presented in this paper. Electromagnetic fields within the planar diode package were analyzed using the finite-element method (FEM). Mixers using the University of Virginia SCIT5 planar diode were designed at both 585 and 690 GHz. A double sideband (DSB) system noise temperature of 2380 K was measured at 585 GHz using 1.16 mW of local oscillator (LO) power, and a system noise temperature of 2970 K DSB was measured at 690 GHz using 1.04 mW of LO power. In addition, the 585 GHz mixer was cooled to both 77 K and 4.2 K, with measured system noise temperatures of 1240 and 880-K DSB using LO powers of 0.47 and 0.14 mW, respectively. The modeling techniques were found to predict the measured conversion loss to within 1 dB. The performance of planar diode mixers is now within a factor of 1.5 of the best whisker-contacted Schottky diode mixers in this frequency range View full abstract»

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  • Parallel computation for microwave circuit simulation

    Publication Year: 1997 , Page(s): 587 - 592
    Cited by:  Papers (4)  |  Patents (1)
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    In this paper, the results of implementing a harmonic balance simulator, AGILE, on a variety of massively parallel computers (MPCs) is given. Descriptions of the computer hardware, which includes both shared-memory and message-passing implementations, and algorithms used to parallelize the computations are presented. The computers used include the CM-5, KSR-1, and a networked set of nonheterogeneous workstations using UNIX RPC. A key aspect is the description of the variety of algorithms used for each computer and the results obtained View full abstract»

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  • Wave propagation in heterogeneous anisotropic magnetic materials

    Publication Year: 1997 , Page(s): 687 - 690
    Cited by:  Papers (4)
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    In order to examine guided wave propagation in unsaturated magnetized materials, it seems reasonable to consider an alternation of layers with antiparallel magnetization in a rectangular waveguide. This approach is coherent with Schlomann's model which considers partially magnetized ferrites as an alternation of antiparallel coaxial cylinders. The finite-difference time-domain (FDTD) method had been used in the case of an homogeneously filled rectangular waveguide. It is adapted here to a guide partially filled with two antiparallel magnetization layers. The modification of the FDTD algorithm at the air/ferrite and ferrite/ferrite interfaces is presented. Results are compared with the ones obtained by a mode-matching technique View full abstract»

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  • Inherently matched Y-junction stripline circulator

    Publication Year: 1997 , Page(s): 648 - 652
    Cited by:  Papers (1)
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    An operation principle based on the field-effect displacement phenomenon of the perpendicularly magnetized ferrite striplines constituting the Y-junction circulator is proposed. The experimental results are in agreement with the idea that the striplines of the junction act as half-wavelength transformers ensuring 5%-8% bandwidth of the investigated circulators in the S-band without external matching View full abstract»

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  • HBT's RF noise parameter determination by means of an efficient method based on noise analysis of linear amplifier networks

    Publication Year: 1997 , Page(s): 690 - 694
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (184 KB)  

    A method for the evaluation of the RF noise figure of heterojunction bipolar transistors (HBTs) is presented. The noise analysis is based on the use of the correlation matrices. The two-port device is described as an interconnection of basic two-port devices whose noise behaviour is known. The circuit theory of linear noisy networks allows that any two-port device can be replaced by a noise equivalent circuit which consists of the original two-port assumed to be noiseless and possess two additional noise sources. The purpose of this paper is to obtain the four noise parameters of the device, taking into account the excess resistances and inductances. The calculations presented show good agreement with measurements, and as a consequence, they permit a good estimation of the noise performance of the structure without neglecting any parasitic elements of the equivalent circuit View full abstract»

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  • SPICE-compatible models for multiconductor transmission lines in Laplace-transform domain

    Publication Year: 1997 , Page(s): 569 - 579
    Cited by:  Papers (8)
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    Two models for multiconductor transmission lines are presented that are compatible with SPICE. One model is based on a Thevenin equivalent circuit and the other model is based on mode decoupling. The models contain controlled generators in the Laplace-transform domain and are able to handle lossy lines with frequency-dependent parameters View full abstract»

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  • Discontinuities in planar chirowaveguides

    Publication Year: 1997 , Page(s): 640 - 647
    Cited by:  Papers (7)
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    In this paper, we propose, develop, and implement an exact method to analyze the effect of discontinuities in open planar chirowaveguides. The method combines the building-block approach of multimode network theory with a rigorous mode-matching procedure. Both the scattering of discrete spectra surface-wave modes and the continuous spectra radiation and evanescent modes are discussed in this paper. The introduction of equivalent transmission-line networks brings new physical insight into the overall behaviour of the discontinuities. Features such as symmetrical properties of the structure are also investigated. Based on the analysis, numerical results are displayed to demonstrate the usefulness of this approach and to discuss mode conversion and radiation characteristics of discontinuities View full abstract»

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  • An MMIC V-band phase-locked oscillator using a GaAs MMIC sampling phase detector

    Publication Year: 1997 , Page(s): 659 - 665
    Cited by:  Papers (8)
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    A V-band full-monolithic phase-locked oscillator (PLO) has been developed. All the circuits are integrated into three monolithic microwave integrated circuit (MMIC) chips. One is a highly integrated multifunction MMIC for 15-GHz voltage-controlled oscillation and 15-30-GHz frequency doubling. The second is for 30-60-GHz frequency doubling. The third is a sampling phase detector (SPD) chip, which operates up to 20 GHz and can be driven at 0-dBm power. Each circuit is greatly reduced in size by using a uniplanar structure; the oscillator area is only 5.5 mm2 and the SPD area is 3.0 mm2. The PLO exhibits output power of 3.5 dBm with single-sideband (SSB) phase noise in the phase-locked state of -64 dBc/Hz at 10 kHz offset from 60.0 GHz in spite of the low Q full-monolithic oscillator circuitry View full abstract»

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  • An accurately scaled small-signal model for interdigitated power P-HEMT up to 50 GHz

    Publication Year: 1997 , Page(s): 700 - 703
    Cited by:  Papers (18)
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    In this paper, the authors report an approach for constructing scalable small-signal models for interdigitated power pseudomorphic high-electron-mobility transistors (P-HEMTs). By using cold-FET and Yang-Long measurement, as well as direct extraction procedures, scaling rules for extrinsic components were established that allow accurate models over a broad frequency range. These models have been used to design ultrawide-band monolithic microwave integrated circuits (MMICs) up to 50 GHz View full abstract»

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  • An improved multigrid technique for quasi-TEM analysis of a microstrip embedded in an inhomogeneous anisotropic medium

    Publication Year: 1997 , Page(s): 678 - 686
    Cited by:  Papers (5)
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    An improved multigrid technique for the quasi-TEM analysis of a microstrip line embedded in an inhomogeneous anisotropic dielectric medium is presented. A general finite-difference form for the inhomogeneous anisotropic medium is derived by the finite-volume discretization of Gauss's theorem. By the analogy between the quasi-TEM and the steady current problems, this general form can be interpreted by Kirchhoff's current law. Then, the electric potential distribution in this complicated dielectric structure can be regarded as that on a resistive network, which makes the formulation easier. The resulting matrix equation for the potential distribution on the finest grid is solved by the improved multigrid iteration, where the coarse-grid operator is derived directly from the finest grid operator by the help of an equivalent resistive network. Three numerical examples show that the convergence rate is hardly dependent of the number of unknowns and the complexity of the dielectric media. Moreover, the numerical results are in good agreement with those by the other method when special cases are considered View full abstract»

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  • Design of compact waveguide twists

    Publication Year: 1997 , Page(s): 636 - 639
    Cited by:  Papers (7)
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    A new geometry for compact twist components composed of rectangular and circular waveguide sections is presented. The proposed twist geometry presents several advantages: 1) It can be designed for any rotation angle; 2) it is extremely short and, therefore, well suited for satellite communication applications; 3) its electrical behaviour is excellent for either narrow or broad frequency bands; and 4) a very accurate and efficient full-wave mode-matching method can be used to analyze these twists. A software package has been developed to design the proposed compact twist structure in a full-wave method View full abstract»

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  • Efficient use of closed-form Green's functions for the analysis of planar geometries with vertical connections

    Publication Year: 1997 , Page(s): 593 - 603
    Cited by:  Papers (39)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (396 KB)  

    An efficient and rigorous method for the analysis of planarly layered geometries with vertical metallizations is presented. The method is based on the use of the closed-form spatial-domain Green's functions in conjunction with the method of moments (MoM). It has already been demonstrated that the introduction of the closed-form Green's functions into the MoM formulation results in significant computational improvement for the analysis of planar geometries. However, in cases of vertical metallizations, such as shorting pin's, via holes, etc., there are some difficulties in incorporating the closed-form Green's functions into the MoM formulation. In this paper, these difficulties are discussed and their remedies are proposed. The proposed approach is compared to traditional approaches from a theoretical point of view, and the numerical implementation is demonstrated through some examples. The results are also compared to those obtained from the commercial software em by SONNET View full abstract»

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  • Micromachined microwave transmission lines in CMOS technology

    Publication Year: 1997 , Page(s): 630 - 635
    Cited by:  Papers (53)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (128 KB)  

    Coplanar waveguides were designed and fabricated through a commercial CMOS process with post-processing micromachining. The transmission-line layouts were designed with commercial computer-aided design (CAD) tools. Integrated circuits (ICs) were fabricated through the MOSIS service, and subsequently suspended by top-side etching. The absence of the lossy silicon substrate after etching results in significantly improved insertion-loss characteristics, dispersion characteristics, and phase velocity. Two types of layout are presented for different ranges of characteristic impedance. Measurements of the waveguides both before and after micromachining were performed at frequencies from 1 to 40 GHz using a vector network analyzer and de-embedding techniques, showing improvement of loss characteristics of orders of magnitude. For the entire range of frequencies, for the 50-Ω layout, losses do not exceed 4 dB/cm. These losses are mainly due to the small width and thickness of the metal strips. Before etching, losses are as high as 38 dB/cm due to currents in the underlying substrate. Phase velocity in the micromachined transmission lines is close to that in free space View full abstract»

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  • Analysis of finite grid structures with lenses in quasi-optical systems

    Publication Year: 1997 , Page(s): 666 - 672
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (168 KB)  

    A full-wave moment-method technique developed for the analysts of quasi-optical (QO) systems is used to model finite grid structures in a lens system. This technique incorporates an electric-field dyadic Green's function for a grid centered between two lenses. This is derived by separately considering paraxial and nonparaxial fields. Results for the driving point reflection coefficient of a 3×3 and 5×5 grid in the lens system are computed and compared with measurements View full abstract»

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  • A Wiener-Hopf-type analysis of uniaxial substrate-superstrate microstrip structures

    Publication Year: 1997 , Page(s): 616 - 629
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (640 KB)  

    A Wiener-Hopf-type technique in conjunction with the hybrid-mode analysis and a space-domain Fourier transform pair was employed for the solution of the canonical problem of a TEM wave obliquely incident upon the edge and defined by a semi-infinite plate conductor lying at the interface of two uniaxial dielectrics, forming an otherwise grounded double-layer geometry. The single-cover layer and double-layer surface-wave modes' characteristic equations are examined and their cutoff conditions, along with safe conditions avoiding longitudinal-section magnetic (LSM) modes are given. The scattered field components and the TEM-wave reflection coefficient are given analytically in the form of Sommerfeld-type integrals. A thin layers approximation and a numerical integration scheme were adopted for the evaluation of the reflection coefficient. Its expression can be directly used for the analysis of wide microstrip lines and patch antennas printed in a substrate/superstrate geometry. The whole analysis gives a clear physical insight into the problem. Furthermore, a twofold theoretical verification was adopted by either forcing the absence of the superstrate or considering both layers to be isotropic. Numerical parametric Investigations show the effects of either the presence of the superstrate or both layers' dielectric anisotropy View full abstract»

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  • Phase noise in coupled oscillators: theory and experiment

    Publication Year: 1997 , Page(s): 604 - 615
    Cited by:  Papers (103)  |  Patents (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (388 KB)  

    Phase noise in mutually synchronized oscillator systems is analyzed for arbitrary coupling and injection-locking topologies, neglecting amplitude noise, and amplitude modulation (AM) to phase modulation (PM) conversion. When the coupling phase is chosen properly (depending on the oscillator model), the near-carrier phase noise is reduced to 1/N that of a single oscillator, provided the coupling network is reciprocal. This is proved In general, and illustrated with specific cases of globally coupled and nearest-neighbor coupled oscillator chains. A slight noise degradation is found for unilaterally coupled (nonreciprocal) chains. The 1/N reduction for reciprocal coupling applies over nearly the entire range of free-running frequency distributions required for beam-scanning, and is verified experimentally using a linear chain of coupled GaAs MESFET voltage-controlled oscillators (VCOs) operating at X-band. The effect of a nonoptimum coupling phase on the phase noise of the system is also studied. As the coupling phase deviates from the optimum value, the phase noise increases significantly near the locking range edge for noise offset frequency near the carrier View full abstract»

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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..

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Jenshan Lin
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