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Microwave Theory and Techniques, IRE Transactions on

Issue 1 • Date January 1957

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  • [Front cover - Jan. 1957 [T-MTT]]

    Page(s): f1 - f2
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    Freely Available from IEEE
  • Table of contents (Jan. 1957 [T-MTT])

    Page(s): 1
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    Freely Available from IEEE
  • Biography - J. R. Whinnery

    Page(s): 2
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    John R. Whinnery was born on July 26, 1916 in Read, Colo. He received the B.S. degree in electrical engineering from the University of California in 1937, and immediately went to work for the General Electric Company in Schenectady, N.Y. At the General Electric Company, Mr. Whinnery entered the three-year Advanced Engineering Program, and following that, supervised the high-frequency part of that program for two years. He then worked in the Electronics Laboratory and the Research Laboratory on problems in velocity-modulation tubes, traveling-wave tubes, and disk-seal triodes. In 1945-1946 he was also part-time lecturer in Union College. View full abstract»

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  • The Next Problem in Engineering Education

    Page(s): 3
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    We have read very much in the past few years of the need for more engineers, so I shall not repeat the arguments here. Many of you have taken part in the very excellent programs designed to acquaint high school students with the opportunities in an engineering career, and I should first like to point out how successful these programs have been. This fact, I believe, is not generally realized. To use our own school as an example, enrollments during the past two years for the university as a whole have risen about 14 per cent, using the same standards of admitting only those among the upper 15 per cent of high school graduates. This rise reflects very nearly the increased birth rate at the end of the depression and the population growth of this area. During this same period, enrollment in engineering has increased about 50 per cent, and in electrical engineering 80 per cent. Although we do not break down the fields of interest further in the early undergraduate years, I believe the proportion of those interested in the microwave field is remaining nearly constant in spite of the competition from several newer fields. View full abstract»

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  • Broad-Band Balanced Duplexers

    Page(s): 4 - 12
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    Balanced duplexer circuits are described and a comparison is made between the two principal configurations employing gaseous switching devices. The balanced tr duplexer is limited in power-handling ability, while the balanced atr duplexer has slightly greater received-signal insertion loss. An analysis is made of the reflecting properties of an atr array, and the practical upper limit of the number of array elements is determined. View full abstract»

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  • Calculation of the Parameters of Ridge Waveguides

    Page(s): 12 - 17
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    In this paper an algebraic expression which constitutes an approximation to Cohn's transcendental equation is given for the determination of the dominant-mode cutoff wavelength of ridge waveguides. A modified derivation of Mihran's equation for calculating the characteristic impedance of ridge waveguides is discussed. Based upon these formulas, nomography are constructed to permit the determination of these parameters with sufficient accuracy when the waveguide and the ridge dimensions vary. Experimental verification of the calculated cutoff wavelength is included. View full abstract»

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  • Excitation of Higher Order Modes in Spherical Cavities

    Page(s): 18 - 22
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    An analysis for determining approximately the optimum position of the exciting source inside a spherical cavity for exciting any TE or TM mode is presented. For any TE or TM mode the orientation of the exciting probe or loop is determined by maximizing the surface integral of /bar H/ or line integral of /bar A/ which is proportional to the excitation coefficient for the corresponding mode. Specific examples of mode discrimination by proper orientation of the exciting source are also included in the paper. Besides, graphs of the surface integral of /bar H/ and the line integral of /bar A/ for various modes are presented to indicate the variation of mutual inductance for any mode, for different positions of the exciting source. View full abstract»

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  • Strip Line Hybrid Junction

    Page(s): 23 - 30
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    The equivalent circuit of a strip line network is shown to display the properties of a hybrid junction. An application is illustrated by design of a balanced mixer and the presentation of the resultant measured data. View full abstract»

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  • Losses in Dielectric Image Lines

    Page(s): 31 - 35
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    The dipole mode in a dielectric rod permits an image system in which half the dielectric and its surrounding field are replaced by a metal sheet. If the field is allowed to extend many wavelengths outside the rod, the resulting line has very low losses. The contribution of the image surface to line loss is calculated, and shown to be generally less than the dielectric loss. Radiation from obstacles along the line is also discussed. Such obstacles in closed single-mode waveguides are useful for matching purposes. Although matching elements are easily constructed for the image line, radiation loss proves difficult to control. View full abstract»

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  • General Synthesis of Quarter-Wave Impedance Transformers

    Page(s): 36 - 43
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    This paper presents the general synthesis of a radio frequency impedance transformer of n quarter-wave steps, given an "insertion loss function" of permissible form. This procedure parallels that of Darlington for lumped constant filters by providing the connection between Collin's canonical form for the insertion loss function and Richards' demonstration that a reactance function may always be realized as a cascade of equal length impedance transformers terminated in either a short or open circuit. In particular, it is shown that insertion loss functions of the form selected by Collin are always realizable with positive characteristic impedances, and that the synthesis procedure, for maximally flat and Tchebycheff performance, involves the solution, at most, of quadratic equations. In addition, this procedure permits the proof of Collin's conjecture that, for his insertion loss function, the resulting reflection coefficients are symmetrical. Finally, closed expressions are given for the coefficients of the input impedance of a given n section transformer in terms of the n characteristic impedances and vice versa. View full abstract»

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  • An Analysis of the Diode Mixer Consisting of Nonlinear Capacitance and Conductance and Ohmic Spreading Resistance

    Page(s): 43 - 51
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    A method is presented for calculating the mixer admittance matrix Y' which results when an ohmic impedance is connected in series with a diode mixer described by an admittance matrix Y. There are no restrictions on the frequency dependence of the ohmic impedance nor on the number of harmonic sidebands considered. The equations are worked out in detail for the "low Q" case in which signal, image, and intermediate frequencies are considered, and it is shown that Y' in this case is "nearly low Q." As a result of this analysis the usual criterion for good high-frequency mixing, i.e., that the product of the spreading resistance and the barrier capacitance be small compared with unity, is criticized and a new figure of merit is proposed. Explicit formulas have been derived for calculating the elements of Y' when Y represents the parallel combination of a nonlinear conductance and capacitance. In general, these formulas are cumbersome, but three special cases have been considered in detail. View full abstract»

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  • Resonance Properties of Ring Circuits

    Page(s): 51 - 56
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    The ring guide or ring circuit, a microwave device consisting of a waveguide having the ends connected to form an annular ring, has properties similar to those of ordinary resonant cavities. Wave propagation within the ring guide, its interaction with a waveguide to which it is coupled, and its resonant circuit properties are investigated in this report. The properties of a prototype circuit consisting of a ring guide of rectangular cross section were found to agree with theory. View full abstract»

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  • Frequency Stabilization of a Microwave Oscillator with an External Cavity

    Page(s): 57 - 62
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    This paper describes a procedure by which a cavity stabilizer may be designed for a microwave oscillator. Formulas are derived for the following essential design parameters: 1) stabilization factor; 2) stabilization range; 3) vswr of the stabilizer circuit with cavity tuned; 4) vswr of the stabilizer circuit with the cavity detuned; and 5) insertion loss of the cavity assembly. The validity of designing with the derived relations has been experimentally confirmed. View full abstract»

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  • Cooling of Microwave Crystal Mixers and Antennas

    Page(s): 62 - 63
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    The development of low-noise mixer crystals has reached the point where the noise figure is approaching fundamental, theoretical limits. The desire for still greater sensitivity has led to the consideration of other possible means for noise reduction. This paper will discuss two possibilities: physically cooling the mixer crystal, and using an antenna directed toward background noise which is lower than room temperature. The improvement which can be realized increases rapidly as the room-temperature noise figure is reduced. View full abstract»

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  • Measurement and Control of Microwave Frequencies by Lower Radio Frequencies

    Page(s): 64 - 68
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    From the fields of nuclear and paramagnetic resonance comes a relation between precession frequency and magnetic field strength for nuclei and unpaired electrons. The relation is such that fn=KnH for nuclei and fe=KeH for electrons. Thus if the frequency of one oscillator is set for fn and the frequency of another oscillator is adjusted so that simultaneous nuclear and electronic resonance occurs in the same magnetic field, the frequency ratio of the oscillators is given by the ratio of Ke to Kn. Values of Ke and Kn have been tabulated for many substances and therefore allow frequency comparisons to be made. For example, protons in mineral oil and electrons in hydrogen have a precession frequency ratio of 658.228; hence for an fe in x band, fn is about 14 mc when the magnetic field is 3300 Gauss. Changing the value of H causes the frequencies to move up or down the frequency scale but their ratio is always constant. By this method microwave frequencies may be measured with equipment of a much lower frequency range. The precision of measurement is limited by the widths of the nuclear and electronic resonance curves and runs between one part in 104 to 105. This frequency measurement method may be made the basis of automatic control of microwave frequencies by quartz crystals or very stable lower frequency oscillators. An experimental model of such a system has been constructed and operated. View full abstract»

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  • Discontinuities in a Rectangular Waveguide Partially Filled with Dielectric

    Page(s): 68 - 74
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    The modal spectrum for a rectangular waveguide with a dielectric slab at the bottom of the guide is obtained following the Characteristic Green's Function method developed by Marcuvitz. Then a four-terminal network is found as equivalent to the junction of the partially filled waveguide and an empty rectangular waveguide. An integral equation is written for the electric field at the plane of the junction and variational expressions are derived for the parameters of the four-terminal network connecting the transmission line equivalent to the partially filled waveguide to the transmission line equivalent to the empty guide. A reasonable guess for the electric field at the discontinuity gives approximate values for the parameters of the four-terminal network. These values agree with experiment. The parameters of the network are plotted vs frequency and thickness of the slab. View full abstract»

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  • Freely Available from IEEE
  • Planar Transmission Lines--I (Addendum)

    Page(s): 75
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    If it is desired to use fine wires of diameter a instead of these flat strips, an elementary argument shows that the characteristic impedance is given. View full abstract»

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  • Optimum Bandwidth for Waveguide-to-Coaxial Transducers (Correspondence)

    Page(s): 75 - 77
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    Mumford has determined a method for optimizing the bandwidth of waveguide-to-coaxial transducers. View full abstract»

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  • [Back cover]

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

Aims & Scope

This Transactions ceased publication in 1962. The current retitled publication is IEEE Transactions on Microwave Theory and Techniques.

Full Aims & Scope