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Microwave Theory and Techniques, IEEE Transactions on

Issue 2 • Date Feb. 1982

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Displaying Results 1 - 17 of 17
  • [Front cover - Feb. 1982 Transactions]

    Page(s): f1 - f2
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  • Recent Developments in Fiber Optic Devices

    Page(s): 121 - 131
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    The advent of the fundamental transverse mode laser diode and low loss optical fiber has extended the wavelength range for communication systems into the optical spectrum region. The indispensable elements for the optical communication systems are light source, transmission medium, and detector. Recent developments in this area in Japan, with particular emphasis on the fundamental transverse mode laser diode and low loss quartz optical fiber, are reviewed. View full abstract»

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  • Prediction of Laser Wavelength for Minimum Total Dispersion in Single-Mode Step-Index Fibers

    Page(s): 131 - 140
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    Pulse dispersion in single-mode optical fibers with step-index profiles has been analyzed in the past using asymptotic methods. One of these methods is based on the approximate characteristic equation for the dominant mode of propagation in these structures, obtained using the "weakly guided" condition. Other methods use approximations for certain parameters of this equation. Utilizing numerical methods of differentiation and interpolation, we have developed a method for the analysis of pulse dispersion in these fibers that is based on solutions of the exact characteristic equation. Exact formulas for the parameters necessary for this study have been established and developed to the point where the steps that would follow, involving extensive analytical effort, are replaced by computational procedures. We make comparisons between our method and those that, although based on asymptotic expressions, present the best theoretical characteristics. The differences found are discussed. This method permits greater precision in prediction of the ideal laser wavelength for use with a given single-mode optical fiber. View full abstract»

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  • Equivalent Representations of Nonuniform Transmission Lines Based on the Extended Kuroda's Identity

    Page(s): 140 - 146
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    Kuroda's identity may be extended to circuits consisting of lumped reactance elements and nonuniform transmission lines. It is shown that these circuits are equivalent to circuits consisting of cascade connections of nonuniform transmission lines whose characteristic impedance distributions are different from original ones, lumped reactance elements, and ideal transformers. If a characteristic impedance distribution W(x) of an original nonuniform transmission line is given, a characteristic impedance distribution Z(x) of a transformed nonuniform transmission line may be uniquely obtained using W(x). Moreover, by using these equivalent transformations, network functions of these transformed nonuniform transmission lines can he derived exactly. View full abstract»

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  • A Study on Circular Disk Resonators on a Ferrite Substrate

    Page(s): 147 - 154
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    In this paper, an exact analysis of a circular disk resonator on a magnetized ferrite substrate which can be used for tunable filters and circular polarizing radiators is presented. The method makes use of Galerkin's method applied in the Hankel transform domain and is quite suitable for numerical calculation. The calculated values of the resonant frequencies and unloaded Q's are shown to be in good agreement with the measured data and the validity of the present theory is confirmed. Furthermore, the characteristics of the traveling wave filters are investigated theoretically and experimentally, and their advantages over the standing wave filters are demonstrated in terms of reflection and sensitivity of the Q L on the coupling strength. View full abstract»

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  • Theory and Design of Low-Insertion Loss Fin-Line Filters

    Page(s): 155 - 163
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    A design theory is described for low-insertion loss fin-line filters that includes both higher order mode propagation and finite thickness of the dielectric substrate and the metallic fins. Design data for three-resonator type fin-line filters with several substrate thicknesses are given for midband frequencies of about 15, 34, and 66 GHz. The measured insertion losses in the passband are 0.25, 0.5, and 1.3 dB, respectively, for these three frequencies. View full abstract»

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  • Radial-Symmetric N-Way TEM-Line IMPATT Diode Power Combining Arrays

    Page(s): 163 - 173
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    Circuit design and stability criteria are developed for a new class of IMPATT diode power combiners. These combiners make use of radial-symmetric circuits and provide an optimal integration of device and circuit properties to perform the power adding function. Both lossless N-way combiners and resistively stabilized N-way combiners are considered. Theoretical examples of this combining technique are given at X-band frequencies which make use of realistic experimentally determined IMPATT diode properties. Predictions for a 30-W ten-diode lossless X-band combiner indicate a l-dB locking bandwidth of 300 MHz and 10-dB gain. A 100-W resistively stabilized 10-GHz ten-diode combiner predicts a 150-MHz locking bandwidth, also at 10-dB locking gain. View full abstract»

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  • Tunable Low-Loss UHF Circulator for Cryogenic Applications

    Page(s): 173 - 176
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    A 600-MHz above-resonance circulator operating at 4.2 K has been constructed and successfully tested. Its high isolation (>30 dB), extremely low insertion loss (<0.1 dB), low VSWR (< 1.1), and acceptable instantaneous bandwidth (~6 percent) make it a promising device for utilization in narrow-band very low-noise systems. View full abstract»

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  • The Thermal Response of a Human in the Near-Zone of a Resonant Thin-Wire Antenna

    Page(s): 177 - 185
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    The thermal response of a human in the near-zone of an antenna was determined by numerical procedures. The approach taken was to modify the heat transfer equations for man in air to account for thermal loading due to the energy absorbed from the radiating antenna. The absorbed power density distribution in the human body was determined by considering the body and antenna to be a coupled system in which the resulting system of equations were solved by moment method procedures. This information was then analyzed by a thermal response model consisting of a series of transient conduction equations with internal heat generation due to metabolism, internal convective heat transfer due to blood flow, external interaction by convection and radiation, and cooling of the skin by sweating and evaporation. Internal heating patterns were calculated for two cases: a human in the near-zone of a quarter-wave monopole and a half-wave dipole operating at 45 and 200 MHz, respectively. It was found that negligible heating occurred for antennas with input power levels of less than 50 W. View full abstract»

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  • A Six-Port Reflectometer and its Complete Characterization by Convenient Calibration Procedures

    Page(s): 186 - 192
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    A simple six-port reflectometer and two methods of calibration using either 51/2 or 61/2 standard terminations are described. High precision is obtained using diode detectors, which are calibrated in situ against a single thermistor power meter. The addition of a few extra components provides a moderately accurate visual display in real time over the 1-8-GHz band. View full abstract»

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  • A Broad-Band Amplifier Output Network Design

    Page(s): 192 - 196
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    An analytic design method for a lossy gain-compensating network is presented and the advantages of lossy networks are discussed. Examples of two-stage amplifiers using FET's and bipolar transistors are presented to show the feasibility of this particular network in low power amplifier designs. These amplifiers obtain gains of 15.4+-0.5 dB with a 2.5-dB maximum noise figure in the 4.0--6.0-GHz frequency range and 16.5+-1.2 dB with a maximum input VSWR of 1.78:1 over the 1.0--2.0-GHz frequency range, respectively. View full abstract»

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  • Application of the Galerkin Method for Determination of Quasi TE/sub i0k/ Mode Frequencies of a Rectangular Cavity Containing a Dielectric Sample

    Page(s): 196 - 198
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    A new method determination of quasi TE i0k mode frequencies of a rectangular cavity containing a dielectric sample is presented. A centrally loaded dielectric sample fills completely only one dimension of a cross section of the cavity. The calculations are based on the Galerkin method using a new suitable set of basis functions. The theoretical results are illustrated by experiments. The obtained results of calculations and experiments demonstrate the advantages of the new basis as compared with the classical one. The presented method may be applied for the analysis of two-dimensional boundary problems for various resonant cavities with inhomogeneous filling. View full abstract»

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  • The Conservation of Complex Power Technique and E-Plane Step-Diaphragm Junction Discontinuities

    Page(s): 198 - 201
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    The singular integral equation solution due to L. Lewin and his colleagues for the E-plane step-diaphragm junction discontinuity are extended by the conservation of complex power technique (CCPT). The singular integral equation method provides formulas for the junction susceptance (both with and without a diaphragm) which are valid only in the quasi-static limit. In contrast, the CCPT provides numerical solutions for larger guides. It is applied to a step with a diaphragm of nonvanishing thickness. View full abstract»

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  • Multifrequency Cryogenically Cooled Front-End Receivers for the Westerbork Synthesis Radio Telescope

    Page(s): 201 - 209
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    Four of the fourteen 25-m antennas of the Westerbork Synthesis Radio Telescope have been equipped with 6- and 21-cm wave-length receivers based on cryogenically cooled parametric amplifiers and up-converters. Special care has been given to the design of the input network to achieve maximum sensitivity. An integrated feed launcher and preamplifier system are housed in a dewar at cryogenic temperatures. The receiver noise temperature at 21- and 6-cm wavelength are on the average 14 K and 20 K, respectively. At 21 cm, two systems have even yielded receiver noise temperature as low as 11 K. This paper concentrates particularly on the cooled section of the receiver system. View full abstract»

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  • Patent abstracts

    Page(s): 210 - 213
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    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]

    Page(s): 214
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  • [Back cover - Feb. 1982 Transactions]

    Page(s): b1 - b2
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    Freely Available from IEEE

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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