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Microwave Theory and Techniques, IEEE Transactions on

Issue 7 • Date Jul 1986

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Displaying Results 1 - 19 of 19
  • [Front cover - Jul. 1986 [T-MTT]]

    Publication Year: 1986 , Page(s): f1 - f2
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    Freely Available from IEEE
  • Patent Abstracts, (Jul. 1986 [T-MTT])

    Publication Year: 1986 , Page(s): 842 - 844
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    Freely Available from IEEE
  • [Back cover - Jul. 1986 (T-MTT)]

    Publication Year: 1986 , Page(s): b1 - b2
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    Freely Available from IEEE
  • New Results in Dielectric-Loaded Resonators

    Publication Year: 1986 , Page(s): 815 - 824
    Cited by:  Papers (62)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1088 KB)  

    Analysis of cylindrical dielectric-loaded resonators is reviewed. The fields within the dielectric-loaded region are postulated as the superposition of hybrid, TE, or TM modes of the infinite dielectric-loaded waveguide, while the fields in the end regions of the resonators are described by the superposition of the normal modes of a homogeneously filled waveguide. Numerical results are presented which reveal that accurate representation of the fields in the resonant structure generally require several modes. Hence, the resonant modes cannot be correlated directly with single waveguide modes. A new method for mode identification is proposed. For a wide range of parameters, the resonant frequencies, mode charts, field expansion coefficients, field intensity, and distributions are presented. Excellent agreement of the mode charts with resonant frequency measurement results are obtained. View full abstract»

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  • Conversion Loss in GaAs Schottky-Barrier Mixer Diodes

    Publication Year: 1986 , Page(s): 753 - 760
    Cited by:  Papers (7)
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    In this paper, the intrinsic conversion loss of GaAs Schottky-barrier mixer diodes is analyzed in light of a more accurate diode model. This analysis resolves the discrepancy between the predictions of an earlier intrinsic conversion loss model and expefimental results. In particular, it is shown that a) cryogenic cooling should not degrade the conversion loss, and b) the diode diameter can be smaller than previously predicted before conversion-loss degradation begins to occur, Evidence is also presented which indicates that mixer diodes must be pumped beyond flat-band if the minimum, possible conversion loss is to be obtained. A more complete model of the conversion loss, which includes the parasitic circuit elements, is discussed and found to be in agreement with the qualitative results of the intrinsic conversion-loss model. View full abstract»

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  • Experimental Simulation of Plasma Using Strip Medium (Short Paper)

    Publication Year: 1986 , Page(s): 825 - 828
    Cited by:  Papers (2)
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    A technique for the plasma simulation using a two-dimensional strip medium is developed. The experimental results for, X-band rectangular waveguide and cavity filled with the strip simulated plasma are in good agreement witi the theoretical results and thus validate the simulation. View full abstract»

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  • Microwave Radiation from a Magnetic Dipole in an Azimuthally Magnetized Ferrite Cylinder (Short Paper)

    Publication Year: 1986 , Page(s): 828 - 831
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    The electromagnetic radiation pattern from a ferrite coated dipole antenna is a torus with a point center. By deriving an expression for the far-field electric field and defining a form factor F(Theta), the dilations and contractions of the radiation pattern were evaluated and demonstrated graphically. View full abstract»

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  • Design and Performance of a 45-GHz HEMT Mixer

    Publication Year: 1986 , Page(s): 799 - 803
    Cited by:  Papers (35)
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    A 45-GHz single-ended HEMT mixer has been developed with unity gain and 7-8-dB SSB noise figure over a 2-GHz bandwidth, including an IF amplifier, and 2-dBm output intermodulation intercept. This paper describes its design, structure, and performance. High performance has been achieved by careful attention to the design of the input and output embedding networks. This is the first reported HEMT mixer and the first active mixer above 30 GHz. View full abstract»

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  • Electromagnetic Standard Fields: Generation and Accuracy Levels from 100 KHz to 990 MHz (Short Paper)

    Publication Year: 1986 , Page(s): 832 - 835
    Cited by:  Papers (2)
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    The interest for problems concerning health protection against RF and MW electromagnetic fields is increasing more and more. This requires uniformity in performances supplied by the measurement instruments employed. It follows the importance of accurately evaluating the procedures of field generation and the overall indetermination on the obtainable field strength levels as well as the need of an intercomparison, carried out by means of a traveling standard too, between the laboratories operating in different countries. In this way, the need for standardizing the exposures techniques in the ever increasing number of experiments addressed to the study of biological effects is satisfied, too. For this purpose, an instrumental chain is described. This chain allows the generation of standard electromagnetic fields, in the context of the Italian National Health Service, with frequencies ranging from 100 KHz to 990 MHz and with field strength levels superior to the limits reported in recent international guidelines. Finally, the overall indetermination of the reached field strength levels is evaluated and discussed. View full abstract»

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  • An Absorber-Wall Parallel-Plate Waveguide

    Publication Year: 1986 , Page(s): 761 - 766
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (784 KB)  

    The electromagnetic fields that can propagate through a parallel-plate waveguide having absorber walls are investigated, and it is shown that dominant TMe10 and TEe10 modes can propagate independently with both having a highly-tapered (cosine-type) transverse distribution, a phase velocity slightly exceeding the speed of light, and very low axial attenuation, especially for a wall-spacing large as compared to a free-space wavelength. In other words, such an absorber-guide acts life a corrugated waveguide having "lambda/4" teeth (balanced-hybrid mode) but it does so over virtually an unlimited bandwidth and with little sensitivity to the absorber's characteristics. View full abstract»

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  • Invariant Definitions of the Unloaded Q Factor (Short Paper)

    Publication Year: 1986 , Page(s): 840 - 841
    Cited by:  Papers (3)
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    Equations are presented for computing the unloaded Q factor of a microwave resonator embedded in an impedance-transforming lossIess, reciprocal two-port. Knowledge of the transformation properties of the two-port is not required. View full abstract»

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  • Convergence of Numerical Solutions of Open-Ended Waveguide by Modal Analysis and Hybrid Modal- Spectral Techniques

    Publication Year: 1986 , Page(s): 809 - 814
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (608 KB)  

    Two different methods are considered to deal with open-ended waveguides with an infinite metallic flange. The first one, modal analysis, is valid only when the aperture is radiating into a Iossy medium. The second one is based on a hybrid modal-spectral technique, and it is valid for any medium, with or without losses. The rectangular aperture problem is solved by both methods, and the influence of different parameters on the convergence of numerical solutions is studied for each method. Finally, a comparison between both methods is presented for lossy and low-loss media. View full abstract»

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  • Field Theory Design of Rectangular Waveguide Multiple-Slot Narrow-Wall Couplers

    Publication Year: 1986 , Page(s): 791 - 798
    Cited by:  Papers (36)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (752 KB)  

    A compact narrow-wall multiple-slot coupler suitable for inexpensive and very accurate metal-etching manufacturing techniques is proposed and optimized. A computer-aided design theory based on the method of field expansion of eigenmodes considers the effects of finite insert thickness and higher order mode interaction, step discontinuities, and changes in width. Computer-optimized design data for --20-, --8.34-, and --3-dB couplers in the R140-waveguide band (12.4--18 GHz) are given. These data are transferable into other common waveguide bands, e.g., R620 band (50-75 GHz), by suitable frequency scaling calculations. A metal-etched 12-slot coupler prototype for a midband frequency of about 15 GHz achieves a +-1-dB bandwidth of the --3-dB coupling of about 3.2 GHz together with a measured isolation of typically 35-40 dB (minimum 25 dB at the band limits). The measurements show good agreement with theory. View full abstract»

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  • Dependence of the Multiple-Device Oscillator Injection-Locking Range on the Number of Constituent Devices (Short Paper)

    Publication Year: 1986 , Page(s): 839 - 840
    Cited by:  Papers (1)
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    An analysis of the behavior of an injection-locked multiple. device oscillator is presented. It is shown that the external Q of the oscillator circuit decreases towards a limiting value as the number of devices is increased. This limiting value is determined by the Q of an individual device. It is also shown that improvement of the locking range with an increase in the number of devices is rapid when the locking gain is very low and independent of the increase of the number of devices. View full abstract»

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  • Millimetric Nonreciprocal Coupled-Slot Finline Components

    Publication Year: 1986 , Page(s): 804 - 808
    Cited by:  Papers (41)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (552 KB)  

    Promising preliminary results are presented for isolators and a four-port circulator in novel finline structures in the frequency range 26.5-40.0 GHz. The basic configuration is a ferrite-loaded coupled-slot finline with the ferrite magnetized parallel with the direction of propagation. The nonreciprocal effects of the odd mode propagating alone and of the odd and even modes propagating are described. All structures exhibit a 20-dB isolation bandwidth greater than 3.6 GHz. It is suggested that such structures would also be suitable for higher frequencies. View full abstract»

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  • Normal Modes in an Overmoded Circular Waveguide Coated with Lossy Material

    Publication Year: 1986 , Page(s): 773 - 785
    Cited by:  Papers (15)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1280 KB)  

    The normal modes in an overmoded waveguide coated with a Iossy material are analyzed, particularly for their attenuation properties as a function of coating material, layer thickness, and frequency, When the coating material is not too Iossy, the low-order modes are highly attenuated even with a thin layer of coating. This coated guide serves as a mode suppressor of the low-order modes, which can be particularly useful for reducing the radar cross section (RCS) of a cavity structure such as a jet engine inlet. When the coating material is very Iossy, low-order modes fall into two distinct groups highly and lowly attenuated modes. However, as a/lambda (a = radius of the cylinder; lambda = the free-space wavelength) increases, the separation between these two groups becomes less distinctive. The attenuation constants of most of the low-order modes become small and decrease as a function of lambda2/a3. View full abstract»

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  • Ultra-High-Speed GaAs Monolithic Prescaler and Phase Frequency Comparator IC

    Publication Year: 1986 , Page(s): 786 - 790
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (512 KB)  

    A high-speed, low-power prescaler and phase frequency comparator (PFC) IC for a phase-lock stable oscillator was designed and fabricated on a single chip using GaAs MESFET BFL circuitry. The gate width of the master-slave T-type flip-flops used in designing the 1/32 frequency divider prescaler was determined by circuit simulations. The fabricated 1/32 prescaler operated up to 8.0 GHz while the fabricated monolithic prescaler and PFC IC performed stable division, and phase and frequency comparison at input frequencies up to 4.8 GHz with a chip power dissipation of only 715 mW. View full abstract»

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  • Electromagnetic Waves in Conical Waveguides with Elliptic Cross Section (Short Paper)

    Publication Year: 1986 , Page(s): 835 - 838
    Cited by:  Papers (3)
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    The electromagnetic field in a conical waveguide with an elliptical cross section is calculated with the aid of two scalar potentials which satisfy the Helmholtz equation, the Dirichlet, and the Neumann boundary condition, respectively. The transverse parts of the solutions of the Hehnholtz equation in the sphero-conal coordinate system are products of periodic and nonperiodic Lamé functions, These functions allow a mode definition similar to that for conventional waveguides. Some transverse modal field distributions, together with the corresponding Lamé functions, are graphically represented for a special elliptic conical waveguide. View full abstract»

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  • Asymmetrical Three-Line with Anisotropic Coupled Striplines Substrates

    Publication Year: 1986 , Page(s): 767 - 772
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (528 KB)  

    Analytical methods are presented for the general structure of three-line coupled striplines with anisotropic media for the first time. Two approaches are included one gives variational expressions for the quasistatic parameters of the cases with the uniaxially anisotropic substrates cut with their planar surface at an arbitrary angle to the optical axis, the other gives the rigorous hybrid-mode formulation for the cases with the uniaxially anisotropic substrates cut with their surface perpendicular to the optical axis. Accurate numerical results are presented for the propagation constants as well as the characteristic impedances of various types of three-line coupled striplines with anisotropic media. 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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