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Microwave Theory and Techniques, IEEE Transactions on

Issue 11 • Date Nov 1987

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Displaying Results 1 - 25 of 28
  • [Front cover - Nov. 1987 [T-MTT]]

    Publication Year: 1987 , Page(s): f1 - f2
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    Freely Available from IEEE
  • Patent abstracts

    Publication Year: 1987 , Page(s): 1077 - 1081
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (367 KB)  

    These patent abstracts of recently issued patents of interest to microwave engineers are intended to provide the minimum information necessary for readers to detennine if they are interested in examining the patent in more detail. Complete copies of patents are available for a small fee by writing: U.S. Patent and Trademark Office, Box 9, Washington, DC, USA. View full abstract»

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  • [Advertisement]

    Publication Year: 1987 , Page(s): 1082
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    Freely Available from IEEE
  • [Back cover - Nov. 1987 [T-MTT]]

    Publication Year: 1987 , Page(s): b1 - b2
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    Freely Available from IEEE
  • Capacitance and Inductance Matrices for Multistrip Structures in Multilayered Anisotropic Dielectrics

    Publication Year: 1987 , Page(s): 1002 - 1008
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (624 KB)  

    In this paper we present a unified variational approach to determine the capacitance and inductance matices of generalized multistrip systems embedded in a multilayered iso/anisotropic dielectric lossless medium. The analysis is earned out in the spectral domain to take advantage of previously obtained recurrence relations which calculate the Green's function in the spectral domain. The method leads to a low-order system of linear equations, which is shown explicitly. Examples and comparison with previously published results have been included. View full abstract»

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  • New Quasi-Static Models for the Computer-Aided Design of Suspended and Inverted Mlcroitrip Lhes (Corrections)

    Publication Year: 1987 , Page(s): 1076
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (84 KB)  

    The following errors appeared in the equations of the above paper. View full abstract»

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  • An Efficient Finite Element Method for Nonconvex Waveguide Based on Hermitian Polynomials

    Publication Year: 1987 , Page(s): 1019 - 1026
    Cited by:  Papers (18)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (672 KB)  

    An efficient finite element method (FEM.) in waveguide analysis is described. The method rises Hermitian polynomials to interpolate the field compohent (Ez or Hz) and some of its derivatives at the nodal points, rather than the field components, as in the Lagrangian interpolation case. Element matrices, for a standard triangle, are given for third- and fifth-degree Hermitian polynomials. The appropriate transformations that relate the element matrices of a general triangle to the standard triangle element have been derived. Compared to the broadly used Lagrangian interpolation FEM, the Hermitian FEM has the following advantages 1) a significant reduction of the matrix order needed to compute the eigenvalues and eigenfunction; 2) smooth axial components (Ez or Hz) and continuous transverse field components; 3) low-cost refinement of the mesh near nonconvex corners of the waveguide. These advantages are illustrated by comparing the FEM, with Hermitian polynomials solution, to other solutions for rectangular and ridged waveguides. View full abstract»

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  • Characterization of the Finline Step Discontinuity on Anisotropic Substrates

    Publication Year: 1987 , Page(s): 956 - 963
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (728 KB)  

    An analysis of the finline step discontinuity in either uniaxial or biaxial substrates is presented. The method is based on a spectral-domain hybrid-mode expansion in an enclosed finline cavity in conjunction with Galerkin's method. A numerically stable scattering matrix formulation is used. The effect of substrate anisotropy is described. The results are also compared with published experimental data or those by the modal matching method when the substrate is isotropic. The comparison shows very good agreement. View full abstract»

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  • Plotting Vector Fields with a Personal Computer (Short Paper)

    Publication Year: 1987 , Page(s): 1069 - 1072
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (432 KB)  

    A combination of a personal computer and an x-y plotter is utilized for generating high-quality graphical displays of vector fields. The input data file must specify values of the vector field at a number of equidistant points. Starting points of field lines are determined so that the partial fluxes between any two adjacent field lines are made equal to each other. The construction of the field lines proceeds in a two-step method, utilizing the interpolated values of the field data. View full abstract»

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  • Coupling Between an Abruptly Terminated Optical Fiber and a Dielectric Planar Waveguide

    Publication Year: 1987 , Page(s): 1043 - 1051
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (752 KB)  

    The coupling between an optical fiber and a dielectric planar waveguide is analyzed when both guides are terminated abruptly and are facing each other. Mixed spectrum eigenwave representations of fields are employed inside the waveguides while Fourier integrals are utilized to describe the field in the space between the two guides. A coupled system of integral equations is derived by satisfying the boundary conditions on the terminal planes of both waveguides. A weak guidance approximation is assumed to facilitate the analysis. Numerical results are presented for several coupling geometries. Misalignment losses and coupling optimization phenomena are investigated. View full abstract»

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  • Unified Approach to Wave Diffraction by Space-Time Periodic Anisotropic Media

    Publication Year: 1987 , Page(s): 937 - 945
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (808 KB)  

    The diffraction properties of electromagnetic waves propagating in a planar anisotropic medium with tensor permittivity which is modulated periodically with respect to space and time are analyzed by extending the previous theory for time-invariant anisotropic dielectric gratings. The method applies to any isotropic or anisotropic medium, any polarization of the incident plane wave, and any orientation of the grating vector. The analysis is formulated in a unified matrix form so that calculations can be performed systematically. As numerical examples of the general analysis, the optical diffractions by an acoustic wave in a birefringent crystal and by a cholesteric liquid crystal are treated, where the approximate two-wave analysis is also derived and the accuracy is discussed by comparison with the rigorous analysis. View full abstract»

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  • Improved Error-Correction Technique for Large-Signal Load-Pull Measurements (Short Paper)

    Publication Year: 1987 , Page(s): 1060 - 1062
    Cited by:  Papers (24)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (312 KB)  

    This article presents an improved vector error-corrected calibration technique for the well-known system used for large-signal characterization of oscillator and power amplifier transistors. The calibration procedure is very similar to conventional automatic network analyzer calibration procedures, and all its measurements, except for one power measurement, are performed by the system itself. Therefore, reflection coefficient and power level measurement accuracies of the system at both the input and output ports of the DUT are excellent, and are of the same order of magnitude as those of the automatic network analyzer. View full abstract»

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  • Surface-to-Surface Transition via Electromagnetic Coupling of Coplanar Waveguides

    Publication Year: 1987 , Page(s): 1027 - 1032
    Cited by:  Papers (14)  |  Patents (40)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (600 KB)  

    A transition is investigated which couples coplanar waveguide on one substrate surface (a motherboard) to coplanar waveguide on another substrate surface (a semiconductor chip or subarray) placed above the first. No wire bonds are necessary. A full-wave analysis using coupled line theory is presented and verified experimentally. The use of this transition for coupling to millimeter-wave integrated circuits is discussed. View full abstract»

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  • Measurement of Shielding Effectiveness of Microwave-Protective Suits

    Publication Year: 1987 , Page(s): 984 - 994
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2416 KB)  

    With more restrictive exposure standards and greater public concern about safety from nonionizing radiation, protective clothing to shield workers from dangerous levels of electromagnetic radiation has become imminently important. Tests were conducted of the shielding effectiveness of a number of microwave suits. Fabric attenuations at 10 selected locations on the suit were measured by the waveguide-transmission-loss method to evaluate the material, and relative field strengths at the surface of a full-sized phantom man model exposed to 2450-MHz free-field radiation fields with and without the suit were measured to evaluate the entire suit. The ratio of the incident power required to produce the same output from a diode E-field sensor placed against the synthetic tissue of the model exposed with and without the suit was used as a measure of attenuation. The waveguide measurements are important for a comparative evaluation of the different fabrics, and the free-field measurements are important for evaluating the fabric as well as the suit design and configuration in shielding effectiveness. The Navy suit provided the best performance in terms of shielding effectiveness, with attenuation varying from 34.5 to 48.7 dB, but its flammability constitutes a safety hazard. The Wave Guarde suit was second best, with attenuation varying from 13.2 to 35 dB. The Milliken (20.3-33.7 dB attenuation) and Invascreen (18.7-24.5 dB attenuation) suits provide acceptable protection for E-field polarization parallel to the long axis of the body, but poor protection (2.0- 19.2 dB for the former and 0.4-21.1 dB for the latter) for E-field polarization perpendicular to the body. Localized high-power-density exposures of up to 1000 mW/cm2 for 1 h from a waveguide aperture did not cause material damage to any of the suit fabrics. The Milliken was the most fire retardant, but its shielding performance was the poorest, owing to the large number of openings at the pockets, cuffs, sleeves, and collar. The Invascreen suit is well designed to eliminate the problem, but the shieldlng of the fabric is less effective. View full abstract»

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  • Monolithic Capacitors as Transmission Lines

    Publication Year: 1987 , Page(s): 964 - 970
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (688 KB)  

    The results of network analyzer measurements of high-Q multilayer (monolithic) chip capacitors show that the devices have the characteristics of open-circuited transmission lines. Both standard sizes (MIL-CDR-14 and MIL-CDR-12), ranging in capacitance values from 4.7 to 1000 pF, were tested on microstrip lines. A simple model of a periodically loaded line provides a dispersion relation that accounts for the distribution of resonant frequencies. The orientation of the capacitor with respect to the microstrip affects the occurrence and nature of resonances. This phenomenon is shown to result from a distributed excitation source. The unfolding of the capacitor to produce the periodic line is shdwn to produce anomalies in the dissipation loss when skin depth and electrode thickness are comparable. View full abstract»

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  • Accuracy of Equations for Coupled Slab Lines (Letters)

    Publication Year: 1987 , Page(s): 1075 - 1076
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (200 KB)  

    The determination of the characteristic impedance of coupled slab lines has been a subject of investigation for many years. Following on Frankel's pioneering work [1], Chisholm obtained art accurate analytical solution for the odd-mode impedance of a pair of coupled slab lines [2]. In 1980, Levy presented Chisholm's equations, together with those due to McDermott for the even-mode impedance, in a general form suitable for calculation [3]. He also confirmed the accuracy of the equations with an efficient numerical procedure. View full abstract»

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  • Design of Coupled Microstrip Lines by Optimization Methods (Short Paper)

    Publication Year: 1987 , Page(s): 1072 - 1074
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (288 KB)  

    The design of two coupled microstrip lines is converted into an optimization problem, which is then solved by two methods of nonlinear mathematical programming. New formulas for calculating the first approximation of the solution, i.e., the starting point of the optimization, are given. View full abstract»

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  • Single-Particle Motion in a Large-Orbit Gyrotron

    Publication Year: 1987 , Page(s): 946 - 955
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1024 KB)  

    The perturbation on the zeroth-order motion of individual particles in an axis-encircling, large-orbit gyrotron due to a constant-amplitude TE0ln electromagnetic (em) wave is studied analytically and numerically. Single-particle phenomena such as phase bunching and trapping are studied as a function of the frequency difference between the cyclotron motion and the em wave. Analytic solutions are developed for both trapped and untrapped particles and are compared with exact numerical results. The analytic solutions yield the percentage of trapped particles and an expression for the minimum em field necessary for trapping. It is shown that energy loss depends on first-order terms for trapped particles and on second-order terms for untrapped particles. A specific set of parameters is used to display the results. View full abstract»

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  • SIS Mixer to HEMT Amplifier Optimum Coupling Network (Short Paper)

    Publication Year: 1987 , Page(s): 1067 - 1069
    Cited by:  Papers (7)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (416 KB)  

    The coupling network between a superconductor-insulator-superconductor (SIS) mixer and a high-electron-mobility-transistor (HEMT) amplifier is investigated from the point of view of minimizing the overall noise temperature and also increasing the saturation level of the mixer. The effect of a negative output impedance of the mixer upon the amplifier noise is considered and an optimum negative source resistance is found. The amplifier noise at this optimum negative source resistance is shown to be related to the noise wave coming out of the amplifier input terminals. Key words: SIS, HEMT, low-noise, negative resistance. View full abstract»

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  • Radiation of Millimeter Waves from a Leaky Dielectric Waveguide with a Light-Induced Grating Layer

    Publication Year: 1987 , Page(s): 1033 - 1042
    Cited by:  Papers (27)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (912 KB)  

    A theoretical analysis is presented for the radiation characteristics of millimeter waves in a periodic dielectric waveguide having a light-induced grating layer. The waveguide is assumed to be composed of an insulator (sapphire) slab whose one surface is coated with a high-resistivity semiconductor (silicon) film. A boundary-integral-equation formulation is employed to obtain characteristic solutions of the waveguide. Numerical calculations are made at 94 GHz for both TM and TE polarizations. Estimations of the illumination power required to produce the grating are given. The waveguide presented in this paper, in conjunction with a high-power semiconductor diode laser array as a light source, may be developed to operate as an electronically beam-steerable leaky-wave antenna at millimeter-wave frequencies. View full abstract»

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  • A Comparative Statistical Study of Some Proposed Six-Port Junction Designs

    Publication Year: 1987 , Page(s): 971 - 977
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (712 KB)  

    Reflection coefficient measurements obtained from six-port reflectometers are analyzed from a statistical and geometrical point of view. The analysis concentrates on the effect of using noisy power meters, and a simply computed, geometrically interpretable estimator of the reflection coefficient possessing certain optimality properties is derived. A suitable performance measure for this estimator is calculated for a number of different six-port designs as the true reflection coefficient ranges over the area of the Smith chart. For each design, a contour map of the measure allows for easy comparison of the designs in different regions of the Smith chart. View full abstract»

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  • Optimized E-Plane T-Junction Series Power Dividers

    Publication Year: 1987 , Page(s): 1052 - 1059
    Cited by:  Papers (36)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (784 KB)  

    A rigorous design theory for compact rectangrdar waveguide power dividers with unsymmetrical series E-plane T-junctions of suitably optimized different waveguide heights and distances is described. The method is based on field expansion in normalized eigenmodes which yield directly the modal S-matrix of two appropriate key building blocks. The immediate modal S-matrix combination of the individual structures includes the effects of all step discontinuities and their mutual higher order mode interaction. Computer-optimized -3.01 dB, -4.77 dB, and -6.02 dB power divider examples achieve about +-0.25 dB coupling deviation at the output ports, together with about 30 dB return loss at the input port, for the chosen design frequencies of 12 GHz, 31.6 GHz, and 15.5 GHz. The -4.77 dB power divider provides a bandwidth of about 8 percent. The theory is verified by measurements. View full abstract»

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  • A Coupled-Mode Approach to the Analysis of Fields in Space-Curved and Twisted Waveguides

    Publication Year: 1987 , Page(s): 978 - 983
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (584 KB)  

    A coupled-mode approach for solving Maxwell's equations in terms of unitary and reciprocal unitary vectors is deduced in a twisted space-curved coordinate system. Application of this method to the analysis of fields in a space-curved and twisted single-mode optical fiber and a twisted rectangular microwave waveguide is presented and compared with the results from existing literature. View full abstract»

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  • Generalized Lorentz Gauge and Boundary Conditions in Partially Dielectric-Loaded Cylindrical Waveguide (Short Paper)

    Publication Year: 1987 , Page(s): 1065 - 1066
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (232 KB)  

    A generalized Lorentz gauge condition for the set of Vlasov-Maxwell equations is introduced. The condition is applied to the free-electron-laser instability of a relativistic electron beam in a partially dielectric-loaded waveguide. For the dielectric-loaded system with the external wiggler magnetic field, the potential approach with the generalized Lorentz gauge rather than the field approach is shown to be more convenient in the self-consistent study of free-electron-laser instability. We also derive the boundary conditions for potentials to be satisfied at the vacuum-dielectic interface and show that they are equivalent to the BTheta and ETheta continuous conditions in the field approach. An example is discussed to illustrate the equivalence between the two approaches of potentials and fields. View full abstract»

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  • Optoelectronic Pulse Compression of Microwave Signals

    Publication Year: 1987 , Page(s): 1014 - 1018
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (576 KB)  

    Optically switched transmission line resonators are shown to generate short microwave pulses of higher output peak power than the CW input signal. This kind of pulse compression is achieved by using the resonator as a storage element and an optoelectronic switch as the output mirror. A theoretical analysis of the efficiency of this device is presented. Experimentally, a peak power enhancement of 14 has been observed at a frequency of 1 GHz. A comparison with numerical results is finally carried out. 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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