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Microwave Theory and Techniques, IEEE Transactions on

Issue 1 • Date Jan. 1999

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Displaying Results 1 - 22 of 22
  • Comments on "Revisiting characteristic impedance and its definition of microstrip line with a self-calibrated 3-D MoM scheme"

    Publication Year: 1999 , Page(s): 115 - 119
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (142 KB)  

    The original paper (see IEEE Microwave Guided Wave Lett., vol. 4, no. 2, p. 87-9, 1998) proposed a means of determining the TEM equivalent Z/sub 0/, which is similar to the technique described by this author. While this author assumes the port discontinuity to be a single shunt capacitance, the port discontinuity assumed by Zhu and Wu is more general. Their key figure is repeated. The transmission line under consideration has a width of 0.635 mm, with a substrate 0.635 mm thick with a relative dielectric constant of 9.7. Zero thickness and zero loss are assumed. Although incidental to this letter, it is interesting to note that Zhu and Wu show the same nonmonotonic dispersion in Z/sub 0/. The authors of the original paper suggest that the 2% difference is due to error in Rautio's analysis. In order to check this hypothesis, an error analysis must be performed. The purpose of this paper is to communicate the results of just such an error analysis for Rautio's analysis. The original authors give their reply. View full abstract»

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  • Capacitance extraction of 3-D conductor systems in dielectric media with high-permittivity ratios

    Publication Year: 1999 , Page(s): 18 - 26
    Cited by:  Papers (8)  |  Patents (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (324 KB)  

    We describe a perturbation formulation for the problem of computing electrostatic capacitances of multiple conductors embedded in multiple dielectric materials. Unlike the commonly used equivalent-charge formulation (ECF), this new approach insures that the capacitances are computed accurately even when the permittivity ratios of the dielectric materials are very large. Computational results from a three-dimensional multipole-accelerated algorithm based on this approach are presented. The results show that the accuracy of this new approach is nearly independent of the permittivity ratios and superior to the ECF for realistic interconnect structures View full abstract»

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  • Rectangular modes and dyadic Green's functions in a rectangular chirowaveguide. II. Results

    Publication Year: 1999 , Page(s): 74 - 81
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1612 KB)  

    For pt. I see ibid., vol. 47, no. 1, p. 67-73 (1999). A general expression of spectral-domain dyadic Green's function (DGF) in a rectangular chirowaveguide has been represented in Part I of this paper. As an application of the theory developed, this paper represents an analytic solution of electromagnetic (EM) wave propagation in the rectangular chirowaveguide. Firstly, the results of EM fields in closed form are obtained by using the DGF decomposition method, which is essentially a combination of the wavefield decomposition method followed by eigenfunction expansion of DGF. Secondly, the novel features of the analytically derived dispersion relations are analyzed and the effects of chirality on the novel features of the dispersion relations and propagation constant are discussed. Distributions of magnetic and electric fields of different order of modes are derived analytically and are then represented in vector field plots and contour plots. Also, the effects of chirality responsible for both plots are discussed. Finally, comparisons between part of the current results and those available in the literature are made. It is observed that this analysis encompasses all the published novel features for a rectangular chirowaveguide, in addition to some newly observed features. The analysis in this part of the paper confirms the applicability of the theoretical analysis given in Part I View full abstract»

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  • Analysis and design of novel structures of artificial transmission lines for MMIC/MHMIC technology

    Publication Year: 1999 , Page(s): 99 - 102
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (176 KB)  

    In this paper, some new types of artificial transmission lines, compatible with monolithic-microwave integrated-circuit/miniature hybrid-microwave integrated-circuit technology are presented. In the new designs, short subsections of different lines are connected together to achieve the needed performance of various transmission-line functions such as impedance transformation, power coupling, etc. Theoretical calculations are given and some typical design data are provided, including models of extremely low impedance lines, which are very practical in the design of microwave power amplifiers and oscillators using heterojunction bipolar transistors or high electron-mobility transistors. Calculation results are validated by simulations and experiments. The proposed structures are very flexible and can easily provide transmission lines with widely varying characteristics View full abstract»

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  • Microwave diversity imaging using six-port reflectometer

    Publication Year: 1999 , Page(s): 84 - 87
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (184 KB)  

    A microwave diversity imaging system conventionally uses a vector network analyzer (VNA) to directly measure the object scattered field (amplitude and phase) over a selected frequency range and viewing angles, then reconstructs the scattering object characteristic function through two dimensional Fourier inversion. In this paper, we present a cost-effective microwave diversity imaging system using a six-port reflectometer, which measures four amplitude (or power) values to acquire the object scattered field indirectly. One can then eliminate the coherent detectors in a VNA. The calibration procedure for this microwave diversity imaging measurement is also described. Experimental results of three types of scattering objects, a metallic cylinder, four distributed line scatterers, and a 72:1 scaled B-52 aircraft model, are presented using the described six-port microwave imaging system View full abstract»

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  • Rectangular modes and dyadic Green's functions in a rectangular chirowaveguide. I. Theory

    Publication Year: 1999 , Page(s): 67 - 73
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (260 KB)  

    An analytic solution of electromagnetic-wave propagation in a rectangular chirowaveguide is represented in this paper in terms of spectral-domain dyadic Green's functions (DGF's) in a general form. The method used here is a combination of a wavefield decomposition method and DGF eigenfunction expansion technique. This DGF decomposition method avoids having to use the modified and normalized vector wave functions, which are found difficult to satisfy the boundary conditions of chirowaveguides in which the reconciliation of Dirichlet and Neumann conditions is impossible. On the other hand, this method can be generalized to a chirowaveguide of arbitrary cross section and is found reducible to a nonchiral case. It is observed that in a similar fashion to the conventional rectangular waveguide, the duality between the electric and magnetic types of DGF's in the rectangular chirowaveguide does not exist. To show the reducibility of the generalized DGF's for bi-isotropic media, we summarized the procedure of utilizing the formulas and proved in detail that the form of the DGF's can be reduced to that for chiral media and achiral (isotropic) media. Exactly the same DGF's are obtainable for the isotropic media by reducing the general formulas. The electric and magnetic fields in the rectangular chirowaveguide due to a point dipole excitation oriented in the y-direction are derived. The detailed numerical analysis includes the novel features of the dispersion relations, the effects of chirality on the novel features of the rectangular chirowaveguides, some newly discovered features, and vector field plots and contour plots of higher order modes of electric and magnetic fields View full abstract»

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  • A novel waveguide-to-microstrip transition for millimeter-wave module applications

    Publication Year: 1999 , Page(s): 48 - 55
    Cited by:  Papers (29)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (280 KB)  

    A novel waveguide-to-microstrip transition is developed using a new design methodology based on iris coupling. Key features of the design are a single-layer substrate, new matching topology, and new cavity enclosure. The transition lends itself to a low-cost implementation, while maintaining the enclosure's hermetic integrity. An extensive tolerance study shows that the present design is robust and very stable with respect to manufacturing and assembly variations. Careful consideration has been given to the mechanical aspects of the transition's implementation in order to achieve seamless integration into the overall package manufacturing and assembly process without sacrificing electrical performance. Proof of concept was achieved by implementing a Q-band (f0=44.5 GHz) design on alumina, a W-band (f0=94 GHz) design on z-cut quartz, and a W-band design on fused silica. All exhibited better than 22 dB return loss at their center frequencies with less than 0.3 dB insertion loss, and at minimum a 10% 15 dB return-loss bandwidth View full abstract»

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  • New compensation functions for efficient excitation of open planar circuits in SDM

    Publication Year: 1999 , Page(s): 106 - 108
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (116 KB)  

    The spectral-domain method is a very fast and powerful technique to analyze planar microwave circuits. However, available techniques for simulating the excitation of open planar microwave circuits are not very effective at relatively low frequencies. In this paper, new compensation functions are introduced, which correctly model the excitation over the whole microwave frequency region View full abstract»

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  • An analytical and numerical analysis of several locally conformal FDTD schemes

    Publication Year: 1999 , Page(s): 56 - 66
    Cited by:  Papers (33)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (376 KB)  

    The virtues of the finite-difference time-domain (FDTD) method for the electromagnetic analysis of arbitrary complex metal and dielectric structures are well known. Almost equally well known are the difficulties encountered by the technique when the material boundaries do not coincide with the Cartesian mesh. Until recently, there were few alternatives to the simple, but inaccurate, staircase approximation for these cases. However, over the past few years, there have been several solutions proposed, which maintain the simplicity and efficiency of the FDTD method while providing an accurate treatment of curved, offset, or sloping metallic boundaries. In this paper, analytical and numerical comparisons are presented and a clear recommended method is shown to emerge View full abstract»

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  • Accuracy estimation of mixed-mode scattering parameter measurements

    Publication Year: 1999 , Page(s): 102 - 105
    Cited by:  Papers (15)  |  Patents (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (124 KB)  

    The pure-mode vector network analyzer (PMVNA) provides direct measurement of differential circuits. Residual error models are derived for the PMVNA and a traditional four-port vector network analyzer (FPVNA). The residual error models are used to calculate the maximum and root-mean-square uncertainties in measurements of mixed-mode scattering parameters of a typical differential amplifier. The uncertainties produced by the PMVNA are compared to the transformed mixed-mode S-parameters of the FPVNA. The PMVNA is shown to have lower uncertainty when measuring differential devices View full abstract»

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  • Calibration procedures with series impedances and unknown lines simplify on-wafer measurements

    Publication Year: 1999 , Page(s): 1 - 5
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (168 KB)  

    Procedures to calibrate network analyzers using unknown calibration lines and series impedances are presented. These LZY and LZN self-calibration procedures are specifically suited for measurements on planar and integrated circuits. By means of the self-calibration algorithm, the propagation constant of the line standards and the quantities of the reflection standards Y and N are determined. The LZN procedure requires three two-port standards, whereas the LZY procedure deals with two standards only. The fact that it is neither necessary nor advisable to know all standards completely allows the realization of the planar calibration standards in an easy way. Both self-calibration procedures according to the seven-term model are based on closed mathematical solutions so that the accuracies are good, as demonstrated by measurement results View full abstract»

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  • Pulse-time modulation of mutually coupled arrays of oscillators

    Publication Year: 1999 , Page(s): 34 - 41
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (356 KB)  

    This paper specifies the coupling parameters for multioscillator arrays (2" in number) such that nondegenerate symmetric and antisymmetric states may be sequentially accessed by electronic control of the coupling parameters. A requirement of this coupling configuration is that, when mutually locked, the oscillator amplitudes are identical to one another. Thus, when the oscillator signals are combined with a series of magic-T's, the output power is the sum of the oscillator powers in the array minus some small loss in the coupling circuit for the symmetric state and zero for the antisymmetric state. Switching from one state to the other is accomplished by control of the feedback phase delay between oscillators. Ideal oscillator cases are analyzed for two, four, and higher numbers of oscillators by induction. By this electronic-mode control of mutually locked oscillators, we have been able to generate pulse-time modulation (PTM) signals which are useful for communication systems. We describe some results of an X-band PTM signal generator View full abstract»

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  • Compact and broad-band three-dimensional MMIC balun

    Publication Year: 1999 , Page(s): 96 - 98
    Cited by:  Papers (54)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (272 KB)  

    This paper presents a simple and effective technique which compensates for the amplitude and phase differences of the Marchand balun. Compensation is accomplished by interconnecting a short transmission line to a pair of couplers. As a result, Marchand balun with operation frequency ranging as wide as 8.2-30 GHz is achieved. To fabricate the prototype, we adopt three-dimensional monolithic-microwave integrated-circuit technology together with a 2.5 μm×4 layer polyimide structure stacked over a GaAs wafer. The topology yields a circuit area as small as 0.2 mm×0.4 mm for the balun View full abstract»

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  • On-wafer characterization of millimeter-wave antennas for wireless applications

    Publication Year: 1999 , Page(s): 92 - 96
    Cited by:  Papers (22)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (188 KB)  

    This paper demonstrates a deembedding technique and a direct on-substrate measurement technique for fast and inexpensive characterization of miniature antennas for wireless applications at millimeter-wave frequencies. The technique is demonstrated by measurements on a tapered slot antenna (TSA). The measured results at Ka-band frequencies include input impedance, mutual coupling between two TSA's, and absolute gain of TSA View full abstract»

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  • On the design of a series-feedback network in a transistor negative-resistance oscillator

    Publication Year: 1999 , Page(s): 42 - 47
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (280 KB)  

    This paper presents a review and exposition to the design of the series-feedback network commonly used in a negative-resistance transistor oscillator. An appropriate selection of the feedback network can significantly increase the negative resistance of the two-port network and is, therefore, an important design step. Three methods, the third being a CAD method, are given for the design of the series-feedback network with examples that help illustrate the procedures used in each method. Furthermore, the examples show the agreement amongst the three methods View full abstract»

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  • Direct extraction of HBT equivalent-circuit elements

    Publication Year: 1999 , Page(s): 82 - 84
    Cited by:  Papers (28)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (120 KB)  

    We present an analytical method for determining the heterojunction bipolar transistors (HBT's) equivalent-circuit elements. Its special feature is that it does not need measurements of test structures nor optimizations. The new algorithm for extracting the intrinsic elements exploits the information contained in the frequency dependence of the network parameters. This leads to a fast algorithm with a unique solution. The method is validated treating GaInP-GaAs HBT's View full abstract»

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  • Approximation of state functions in measurement-based transistor model

    Publication Year: 1999 , Page(s): 14 - 17
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (148 KB)  

    This paper investigates the use of approximation of state functions in measurement-based transistor models. This is especially important when these models are used in third-order intermodulation distortion simulations since the dynamical spline interpolation that is typically used has possible large discontinuities in its third-order derivative. We, therefore, propose a new representation of the state functions in our model and offer a comparison between measurement and simulation to prove the validity of our approach. Also, our model can easily be implemented in any commercially available SPICE simulator, which also is a significant advantage View full abstract»

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  • Characterization of high-Q resonators for microwave filter applications

    Publication Year: 1999 , Page(s): 111 - 114
    Cited by:  Papers (28)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (168 KB)  

    A one-port reflection technique is developed to measure the unloaded Q and external Q of a microwave resonator. The unique procedure of measuring unloaded Q is outlined in three easy steps. A sample chart is provided to further simplify the process. This method is so simple that even a scalar network analyzer is adequate for the measurement. In addition, a time-delay response around the resonator resonant frequency is also derived and presented. This theoretical result, combined with the advanced capability of modern vector network analyzers, has been proven to be very useful for characterization and tuning of the external Q of a resonator. All the results derived are verified by practical measurement. Finally, this technique is applied to the realization and tuning of a six-pole dielectric loaded cavity filter View full abstract»

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  • A novel quasi-optical resonator for the surface near-millimeter waves

    Publication Year: 1999 , Page(s): 27 - 33
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (196 KB)  

    The theory and experimental investigations are presented for a new type of quasi-optical near-millimeter-wave prismatic resonator, which provides frequency selective transformation of the plane waves into the surface waves. Theoretical expressions are obtained for the Q-factor and finesse, which consider dielectric loss and the effect of prism finite aperture. The theoretical evaluations are verified by experimental measurements in the frequency range 300-500 GHz using a prismatic resonator made from the optical quality fused silica glass. The increase of intensity of surface waves by a factor of 10-25 is demonstrated for the prismatic resonator made from an extremely low-loss dielectric View full abstract»

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  • Near-field and far-field prediction of quasi-optical grid arrays

    Publication Year: 1999 , Page(s): 6 - 13
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (320 KB)  

    Field profiles, equivalent isotropic radiated power (EIRP), beamwidth, and sidelobe levels of a quasi-optical power-combining grid amplifier structure are obtained using a whole-field electromagnetic analysis of a finite structure. This is efficiently obtained using a mixed spectral- and spatial-domain method-of-moments technique. It is seen that edge effects can have a significant effect on system performance View full abstract»

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  • Direct measurement of Cbe and Cbc versus voltage for small HBT's with microwave s-parameters for scaled Gummel-Poon BJT models

    Publication Year: 1999 , Page(s): 108 - 110
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (120 KB)  

    A novel method for determining the junction capacitances versus voltage in heterojunction bipolar transistors (HBT's) using s-parameters at microwave frequencies is presented. This new technique has several advantages over traditional approaches, which include: (1) it profiles capacitance at greater forward bias; (2) it enables the direct measurement of minimum geometry transistors; (3) it allows for the accurate extraction of scaled HBT model parameters with emitter length; and (4) it results in improved pad parasitic deembedding for accurate modeling. Both the capacitance-voltage and large-signal HBT model results are shown View full abstract»

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  • Bandwidth and dispersion characteristics of a new rectangular waveguide with two L-shaped septa

    Publication Year: 1999 , Page(s): 87 - 92
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (204 KB)  

    A new rectangular waveguide with two L-shaped septa has been added to the family of septa-loaded broad-band waveguides. Its modal characteristics and dispersion in the inhomogeneously loaded version have been theoretically determined. The cutoff frequency and the bandwidth of the lowest TE mode are also compared with the experimentally measured values obtained with a test cavity 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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