A circuit model is used to present the basis forthe existence of complex propagation constants and backward wave modes in lossless coupled dispersive transmission lines. In particular, for the 2-line lossless case, co...
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A circuit model is used to present the basis forthe existence of complex propagation constants and backward wave modes in lossless coupled dispersive transmission lines. In particular, for the 2-line lossless case, conditions for realizing complex modes, as well as the possible forms for the \omega-\beta diagram are given. Methods for approximating the mode behavior of lossless waveguide systems, uniform in the propagation direction, but with transverse plane inhomogeneities, are presented using coupled-line models. These methods are derived from the Schelkunoff representation of such a waveguide structure by an infinite set of coupled TE and TM dispersive transmission lines. The techniques used in this paper depend on an approximation which reduces the infinite number of lines to a finite number. One approximation method interpolates the parameters of a realizable 2-line system to approximate the behavior of the infinite line system up to a frequency in the vicinity of the secondlowest eigenmode. A second method is a systematic network procedure for eliminating coupling ports of the infinite structure so as to obtain a finite number of coupled lines to approximate the mode behavior. These two methods are illustrated by 2-line models for round waveguide loaded with a dielectric rod. The mode behavior of the loaded guide is surprisingly well approximated by both the 2-line models.
The problem of electromagnetic-wave propagation in junctions between two symmetrically, partially dielectric-filled waveguides was investigated, and the solution is presented in the form of a two-port equivalent circu...
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The problem of electromagnetic-wave propagation in junctions between two symmetrically, partially dielectric-filled waveguides was investigated, and the solution is presented in the form of a two-port equivalent circuit, This equivalent circuit includes an ideal 1:1 transformer, which is connected to transmission lines with impedances equal to those of the two waveguides, in cascade with a T network. Elements of the T network and the characteristic wave impedances of these partially dielectric-filled waveguides have been studied, and the results are presented in graphs for different dielectric constants, slab thicknesses, and operating frequencies.
Elastic, piezoelectric, and dielectric constants of α-HgS (Cinnabar) were measured mainly by the resonant method. Piezoelectric α-HgS thickness transducers when coupled with bulk α-HgS would realize perfect matchin...
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Elastic, piezoelectric, and dielectric constants of α-HgS (Cinnabar) were measured mainly by the resonant method. Piezoelectric α-HgS thickness transducers when coupled with bulk α-HgS would realize perfect matching in acoustooptical applications.
A high-density electron-hole plasma generated within a high-efficiency avalanche diode induces a sharp, high-voltage pulse on a transmission line. A novel gigahertz-rate pulse generator has been constructed utilizing ...
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A high-density electron-hole plasma generated within a high-efficiency avalanche diode induces a sharp, high-voltage pulse on a transmission line. A novel gigahertz-rate pulse generator has been constructed utilizing the high- efficiency microwave avalanche diode. An impedance discontinuity within the circuit gives rise to a sharp pulse with undistorted waveform, which keeps retriggering the diode for a self-excited pulse generation. The peak- to-peak amplitude of the pulse is 125 V into a 50-/spl Omega/ load. The pulsewidth is 400 ps, the rise time 100 ps, and the fall time 200 ps.
The fast computational algorithm based on matrix Kronecker products yields the Hadamard transform in a scrambled order of sequencies. A computational algorithm is developed to arrange the transform in an increasing or...
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The fast computational algorithm based on matrix Kronecker products yields the Hadamard transform in a scrambled order of sequencies. A computational algorithm is developed to arrange the transform in an increasing order of sequencies. The unscrambling is achieved by exchanges of components and requires no additional storage.
This investigation describes analytical and experimental results obtained on a broadband ferrite limiter at K u band which utilizes a synchronously tuned waveguide bandpass structure. This device is aimed at providing...
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This investigation describes analytical and experimental results obtained on a broadband ferrite limiter at K u band which utilizes a synchronously tuned waveguide bandpass structure. This device is aimed at providing protection for communications and electronic warfare systems over a bandwidth from 12 to 30 percent at K u -band frequencies. The circuit consists of a series of three cavities in a waveguide transmission line, the coupling being accomplished via the irises or symmetrical inductive slits between cavities. Because of this cavity structure, the observed threshold power levels have been reduced by an order of magnitude. By utilizing a combination of single crystal YIG and lithium ferrite rods, the threshold power for limiting varies from 0.75 W at 16.0 GHz to 2.0 W at 17.0 GHz with an insertion loss of 0.9 dB.
Using a new sine-plane approach, an easy-to-use design procedure for microwave filters is developed. The design formulas are very simple and are valid for filters of wide bandwidths. Furthermore, the new design offers...
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Using a new sine-plane approach, an easy-to-use design procedure for microwave filters is developed. The design formulas are very simple and are valid for filters of wide bandwidths. Furthermore, the new design offers many advantages over other presently available designs.
An injector has been built at the University of Maryland which produces a hollow cylindrical beam of relativistic electrons. The design uses a low-impedance pulse generator and step-up, transmission-linetransformer to...
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An injector has been built at the University of Maryland which produces a hollow cylindrical beam of relativistic electrons. The design uses a low-impedance pulse generator and step-up, transmission-linetransformer to drive a high-impedance, field-emission electron gun. This paper reviews the design of the pulse generator and performance of the pressurized gas switches. The transformer and electron gun design is also described and results are given for the initial tests of the injector with a 2-MeV, 6-kA beam.
The transient analysis of nonuniform transmission lines is a task that has to be done frequently in varied fields of engineering. Since the analytical solutions exist only in a few cases, numerical algorithms become i...
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The transient analysis of nonuniform transmission lines is a task that has to be done frequently in varied fields of engineering. Since the analytical solutions exist only in a few cases, numerical algorithms become inevitable. This short paper describes a new and simple method of the transient response calculation of nonuniform transmission lines. The new approach uses the electrical distance as an independent variable, and makes it possible to apply the method of characteristics as easily as in the case of uniform lines. The technique is thus more practical than those previously described.
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