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Microwave Theory and Techniques, IRE Transactions on

Issue 6 • Date December 1955

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Displaying Results 1 - 18 of 18
  • [Front cover and table of contents - Dec. 1955]

    Publication Year: 1955 , Page(s): f1 - f2
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  • Foreword (Dec. 1955 [T-MTT])

    Publication Year: 1955 , Page(s): 1
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    To keep our membership abreast of the latest developments in the microwave art, this volume of Transactions is devoted exclusively to the publication of the PGMTT-sponsored papers presented at the Annual 1955 URSI-IRE meeting held in Washington, D. C. The two sessions at which the papers were read were organized by the Group in cooperation with Commission 6 of URSI. The IRE Professional Group on Microwave Theory and Techniques wish to extend their thanks to Dr. E. C. Jordan, Chairman of Commission 6 of the U. S. A. National Committee of URSI and to Dr. W. E. Gordan, Secretary-Treasurer of the National Commission URSI, for their help and advice in the organization of these microwave sessions. View full abstract»

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  • Wave Coupling by Warped Normal Modes

    Publication Year: 1955 , Page(s): 2 - 6
    Cited by:  Papers (15)
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    It has been shown by J.S. Cook that wave power may be transferred from one to another of two coupled waveguides through a variation of their phase constants. It is now clear that this is but one example of a new principle of coupling which is here called "nomal mode warping." Wave power inserted at one end of a coupled waveguide system may be made to appear at the other end with any desired power distribution by gradual warping of the normal mode field patterns along the coupler. In general, both variation of the coupling coefficient and phase constants are required. Much wider bands are theoretically possible than with any other distributed type of coupler. This principle may be applied to dielectric waveguides, birefringent media, and waveguides containing ferrite, to obtain both reciprocal and nonreciprocal couplers. View full abstract»

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  • Investigation of VHF Nonoptical Propagation between Sardinia and Minorca

    Publication Year: 1955 , Page(s): 7 - 12
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    Announcements that VHF and UHF transmission had been found possible over distances considerably greater than classical diffraction theory had predicted, aroused considerable interest in Europe. It was felt that if such transmission proved to be reliable, there would be numerous cases where it could provide circuits more conveniently and, perhaps, more economically, than could conventional transmission systems. View full abstract»

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  • Data on the Temperature Dependence of X-Band Fluorescent Lamp Noise Sources

    Publication Year: 1955 , Page(s): 12 - 17
    Cited by:  Papers (3)
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    This paper is concerned primarily with the performance of fluorescent lamps as microwave noise sources at 9,000 mc. In particular, it deals with the temperature dependence of the excess noise ratio of an 8-watt lamp running at a lamp current of 150 ma in a 10° E-plane holder. It was found that 1) the bulb temperature is much higher than that with a lamp current of 75 ma encountered in the 90° H-plane circuit investigated previously at 4,000 mc, hence the temperature coefficient of excess noise versus waveguide temperature obtained in the 4,000 mc circuit does not apply, 2) anomalous and unreproducible inversions in the temperature coefficient at these higher bulb temperatures have been observed, 3) these anomalies can be avoided by operating the bulb at lower temperatures, 40°C to 50°C, where the lamps appear to be just as uniform and stable and probably just as noisy as they are at 4,000 mc. View full abstract»

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  • Phase Shift by Periodic Loading of Waveguide and Its Application to Broad-Band Circular Polarization

    Publication Year: 1955 , Page(s): 18 - 21
    Cited by:  Papers (26)  |  Patents (2)
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    A rectangular or square waveguide may be loaded periodically by thin capacitive or inductive irises in order to produce phase delay or phase advance, respectively. The amount of phase shift may be calculated with accuracy by making use of available theoretical values of iris susceptance and of transmission line theory. The phase shifting sections maybe designed for low voltage standing-wave ratio (vswr) over a considerable bandwidth. When a square waveguide capable of supporting two fundamental modes is loaded periodically, the irises act inductively for one mode and capacitively for the other, thus introducing a differential phase shift. This differential phase shift may be made equal to 90°, in order to convert linear to circular polarization. Furthermore such a device may be made, by proper choice of parameters, to yield near-circular polarization over a bandwidth of 1.65:1, because the variation in phase delay for one mode and phase advance for the other tend to compensate each other as the frequency is varied. Several of these circular polarizers have been built and tested at X band and the measured results of ellipticity and vswr, as well as broad-band performance check with theoretical values quite closely. View full abstract»

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  • 900-mc PTM Over-the-Horizon Radio Link

    Publication Year: 1955 , Page(s): 22 - 26
    Cited by:  Papers (1)
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    An experimental over-the-horizon radio link has been installed and tested for several months by the Federal Telecommunication Laboratories. Its chief purpose has not been to study propagation, although several interesting results may appear, nor to establish a commercially usable communication facility, but rather to study the application of this relatively unexploited type of propagation to multi-channel transmission, particularly that using ptm, pulse-time modulation. View full abstract»

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  • A Method for the Accurate Measurement of the Noise Temperature Ratio of Microwave Mixer Crystals

    Publication Year: 1955 , Page(s): 27 - 35
    Cited by:  Papers (1)
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    For the precise measurement of noise temperature ratio of a microwave mixer crystal it is common practice to employ a Roberts coupling network in order to make the Y factor independent of crystal conductance. It is shown here that a number of errors are introduced in this method, the chief of which is failure to consider the effect of transit time loading. It is also shown that the use of cathode lead inductance leads to a much improved measurement of noise temperature ratio. View full abstract»

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  • Circuit Components in Dielectric Image Lines

    Publication Year: 1955 , Page(s): 35 - 39
    Cited by:  Papers (13)
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    Symmetry of dipole mode in a dielectric rod permits use of an image system. By replacing lower half of dielectric and its surrounding field with an image surface, support problem is eliminated. Resulting image provides structural convenience and also has very low loss, provided wave is allowed to occupy a cross section many wavelengths square. In millimeter region this is readily achieved. Possibilities of new types of circuit elements in this image system are explored. Combination of optical and waveguide techniques is a characteristic of resulting components. Properties of several transducers between image line and either rectangular waveguide or coaxial line are described. Attenuators, standing-wave detector, and various directional coupler types for image lines are also discussed. View full abstract»

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  • Applications of the Turnstile Junction

    Publication Year: 1955 , Page(s): 40 - 45
    Cited by:  Papers (16)  |  Patents (2)
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    The Turnstile Junction is a six-terminal pair microwave network, consisting of four coplanar rectangular arms and a circular arm, orthogonal to the rectangular arms, which is excited in two orthogonal TE 1, 1, modes. The characteristics of the network are such that they lend themselves to some very important and unique applications in the microwave field. Making use of the symmetry conditions and the field division properties of the Junction, this paper describes the operation of the Junction under various conditions, with particular emphasis on the applications to which these characteristics lend themselves. View full abstract»

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  • The Ultra-Bandwidth Finline Coupler

    Publication Year: 1955 , Page(s): 45 - 48
    Cited by:  Papers (1)
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    The "finline coupler" is a recently developed microwave circuit element with which it has been possible to assemble hybrid junctions, directional couplers, and polarization-selective couplers capable of operating over bandwidths of at least three-to-one in frequency. Constructional details and experimental results are given. View full abstract»

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  • Microwave Traveling-Wave Tube Millimicrosecond Pulse Generators

    Publication Year: 1955 , Page(s): 48 - 51
    Cited by:  Papers (5)
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    For some time, short pulse techniques have played a useful part in the microwave art. In order to obtain better resolution, equipment for generating and viewing microwave pulses about six millimicroseconds long was developed and described previously. The regenerative pulse generator in that equipment was rather complex and difficult to build and adjust. A much simpler generator of pulses with about the same time duration is now being used. It produces short pulses by properly gating a conventional microwave signal source with a traveling-wave amplifier having suitable transient voltages applied to both its helix and its beam-forming electrode. It is easier to construct and operate, requires fewer components, and gives a more stable output. It can be used at any frequency where a signal source and a traveling-wave amplifier are available. The pulse frequency can be set anywhere within the amplifier bandwidth. Both generators are described and compared. Equipment for receiving, displaying, and measuring the pulses is also briefly discussed. Pulse shapes and resolutions are shown on oscilloscope photos. View full abstract»

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  • E-Plane Forked Hybrid-T Junction

    Publication Year: 1955 , Page(s): 52 - 58
    Cited by:  Papers (13)
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    A novel rearrangement of the waveguides of a microwave hybrid-T junction has been investigated. This junction is formed by the intersection of four rectangular waveguides, two of which (conventionally E and H arms) are mutually perpendicular, cross-polarized, and have their centerlines in one symmetry plane of the junction; the remaining two waveguide arms are formed by symmetric E-plane bifurcation of the E-arm waveguide extended. This hybrid T possesses special advantages with regard to match and pulse power capacity. A special test fixture was constructed of 1.122- X 0.497-inch rectangular waveguide. Experimental design work was carried out over a 12 per cent range of frequencies from 8.5 to 9.6 kmc. The H-arm reflection was reduced to 2.6-db standing-wave ratio (swr) by simple shaping of the bifurcating element. Addition of conventional matching elements resulted in maximum reflections, within the above band, of 0.8 and 0.6 db swr in the H and E arms, respectively. The ultimate limitation on the E-arm power capacity, as fixed by the intensified electric field at the leading (rounded) edge of the center partition, was computed to be 2 db below uniform waveguide. Experimental corroboration has been obtained. View full abstract»

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  • A Switch-Detector Circuit

    Publication Year: 1955 , Page(s): 59 - 62
    Cited by:  Papers (6)
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    Crystal circuit is used wherein switching is accomplished by varying dc voltage across a crystal. Impedance of crystal plus its mount varies from low inductive to high capacitive value. Maximum attenuation frequency of high-pass, series m-derived filter varies with change of parallel inductance or capacitance. If crystal is placed across parallel capacitance, and its bias varied, input impedance of filter is changed. As a result, attenuation vs frequency characteristics are varied. Operating parameters of switch are: frequency, 500-1,000 mc; bandwidth, 20 mc; switching, >55 db; average insertion loss, 2 db; switching time, <1/2 µsec; bias voltage, between -0.6 and +0.6 volts. This unit finds application in radar jamming problems, as well as a low power modulator for rf signals. View full abstract»

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  • Noise Measurements in the UHF Range (Abstract)

    Publication Year: 1955 , Page(s): 62
    Cited by:  Papers (1)
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    Comparative noise figure measurements in the 400 mc frequency range have been made using commercial noise diode sources, thermal noise sources, and fluorescent lamps as noise generators. The thermal sources were of two kinds, a high temperature source at about 1,000°K and a low temperature source at 4°K. Measurements made with noise diodes yielded results about 1.0 db higher than those made with the thermal noise sources, from which it is inferred that the diodes are not satisfactory primary standards of noise in this frequency range. The effective noise temperature of a standard 6 w fluorescent tube (coupled to a helical line) was determined to be approximately 12,000°K by comparing its noise output with that of the hot thermal source. This is consistent with the figure of 11,400°K reported by Mumford at 4,000 mc. View full abstract»

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  • The Regeneration of Binary Microwave Pulses (Abstract)

    Publication Year: 1955 , Page(s): 62
    Cited by:  Papers (1)
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    The chief advantage of binary pulse systems resides in the possibility of regenerating such pulses at intervals along the transmission route to prevent the accumulation of distortions due to noise, bandwidth limitations, and other disturbing effects. A very important part of any such transmission system is the regenerative repeater employed. This paper reports the results of experiments performed to determine the possibilities of such a repeater operating in the microwave frequency range. View full abstract»

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  • Contributors (Dec. 1955 [T-MTT])

    Publication Year: 1955 , Page(s): 62 - 64
    Cited by:  Papers (1)
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    Freely Available from IEEE
  • [Back cover - Dec. 1955 (T-MTT)]

    Publication Year: 1955 , 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