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Microwave Theory and Techniques, IEEE Transactions on

Issue 6 • Date Jun. 1974

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Displaying Results 1 - 19 of 19
  • [Front cover - Jun. 1974]

    Page(s): f1 - f2
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    Freely Available from IEEE
  • Foreword, Jun. 1974

    Page(s): 589 - 590
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    Freely Available from IEEE
  • Comments on the Design and Manufacture of Dual-Mode Reciprocal Latching Ferrite Phase Shifters

    Page(s): 593 - 601
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    The design principles for dual-mode reciprocal latching ferrite phase shifters are relatively well understood at present. Discussions of a few selected topics not previously studied are presented in this paper. A tradeoff analysis is carried out for X-band units to show the interrelation between phase-shifter weight and insertion loss. An interesting consequence of this analysis is the theoretical prediction of an optimum range of values for the saturation moment of the ferrite material. Switching energy in the presence of shorted-turn damping is also analyzed and related to the geometry and hysteresis loss of the ferrite material. Finally, a discussion of manufacturing considerations and unit cost at high rates of production is carried out. The major conclusion is that unit cost levels approaching $10.00 are possible for a production run sufficiently large to justify the substantial cost of engineering and tooling for high rates of manufacture. View full abstract»

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  • Computer Analysis of Microwave Propagation in a Ferrite Loaded Circular Waveguide - Optimization of Phase-Shifter Longitudinal Field Sections

    Page(s): 601 - 613
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    A theoretical analysis of the microwave propagation in a circular TE/sub 11/ waveguide partially or completely loaded with an axially magnetized ferrite rod is presented. This study is based upon an exact analytical treatment of the Maxwell's equations, together with an original numerical method of solving transcendental equations with a complex variable. The introduction of the complex propagation constant /spl Gamma/ = /spl alpha/ + j/spl beta/, taking in account the losses in the filling medium, had never been attempted because of the mathematical difficulties involved making essential the use of a large capacity computer. The developed program not only supplies all the propagation characteristics for a given structure but also enables us to optimize a phase-shift section in accordance with the user's requirements. This study is a first step towards the theoretical optimization of two types of reciprocal phasers: the dual mode phaser (DMP) and the polarization insensitive phaser (PIP), both widely used in array antenna systems. The computed results obtained for the basic section of such phasers operating at a central frequency of 9.5 GHz are given. Obviously, this work is still incomplete since it does not include the optimization of all the components of a practical phase shifter, for example, the polarizers. Moreover, we have assumed the ferrite partially magnetized by a continuously variable bias field, although the PIP and the DMP are normally operated in a latching configuration; we presently complete our study according to these practical considerations. View full abstract»

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  • Freely Available from IEEE
  • [Back cover]

    Page(s): b1 - b2
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  • A Low Cost P-l-N Diode Phase Shifter for Airborne Phased-Array Antennas

    Page(s): 688 - 692
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    This paper presents a description of a p-i-n diode phase shifter that was designed for low cost production for use in X-band phased-array systems. The phase shifter is designed to make maximum use of photoetched circuit components and low cost materials, and is well suited for assembly on a fully automated assembly line. The salient features of this phase shifter are a printed-circuit transmission structure and inexpensive RF connectors that are integrated into the circuit package. The microwave performance characteristics are generally superior to those of equivalent devices; a useful bandwidth of 40 percent with an average insertion loss of 1.6 dB has been demonstrated with 3-bit units. View full abstract»

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  • Design of a Broad-Band 4-Bit Loaded Switched-Line Phase Shifter

    Page(s): 693 - 697
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    A 4-bit p-i-n diode switched-line phase shifter was fabricated for use in the 2.0- to 4.0-GHZ frequency range. Extremely good phase characteristics were easily obtained over two octaves by employing a resistive loading technique to eliminate resonance problems. A single bit was modeled and analyzed on a computer from 1.5 to 6.0 GHz. Test results of a microstrip realization of this bit, which correlates well with the computer model, are presented. A unique compatible driver used with the phase shifter, and the microstrip fabrication process used in constructing the phase shifter are also presented. View full abstract»

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  • Practical Aspects of Phase-Shifter and Driver Design for a Tactical Multifunction Phased-Array RADAR System

    Page(s): 617 - 625
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    Three microwave garnet phase-shifter designs are used in the AEGIS weapons system. The microwave design is straight-forward except that the toroid assembly is potted with silicone rubber to increase its power-handling capability and the magnetizing wires are shielded with a spiral-wrapped wire to prevent the propagation of higher order modes. The driver circuit uses a new "flux-feedback" concept for improved accuracy and employs monolithic circuits, hybrid circuits, and discrete components. Mechanical and electrical design of the interfaces with mating components are important cost considerations and the chosen designs are described in detail. Several techniques for improving production yield are discussed and a table of production statistics is provided. Performance histograms and data averages as a function of time and operating frequency are also presented. View full abstract»

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  • High Average Power S-Band Digital Phase Shifter

    Page(s): 626 - 634
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    A 100-kW-peak Z-kW-average-power liquid-cooled ferrite digital phase shifter has been constructed using beryllia cooling of the ferrite toroid to meet single axis scanned array requirements. The phase-shift cross section external to the ferrite toroids is completely filled with the beryllia. Experiments indicate that the maximum temperature rise in the ferrite is no greater than 45° C. In tests using flux drive to 2 kW, the phase shifter exhibits a maximum phase drift of ± 6° for 90° differential phase shift. The differential phase shift versus frequency varies less than ± 0.5° for a 3-percent bandwidth. View full abstract»

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  • A Phase-Locking Method for Beam Steering in Active Array Antennas

    Page(s): 698 - 703
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    A new principle for phase shifting, and hence beam steering, on an active array antenna is described. Each individual RF source is phase locked by a stable locking signal which is close in frequency to the nth harmonic of its free-running frequency. Pulses of appropriate amplitude and duration applied to the dc circuitry cause the fundamental output frequency of the RF source to shift in phase by increments of 2π/n. The construction and testing of a four-element L-band (1-GHz) array using transistor oscillators locked at S-band (4 GHz) to give 90° phase increments is described. View full abstract»

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  • Effective Phase-Shifter Cost as a Selection Criterion

    Page(s): 591 - 593
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    In order to select a phase shifter for a given application, it is necessary to weigh a number of performance factors such that the device selected will result in the lowest overall system cost. This may be accomplished by defining an effective phase-shifter cost in terms of the initial cost of the phase shifter and driver, and dollar factors resulting from insertion loss, phase error, and quantization level. View full abstract»

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  • A Low-Cost Construction Technique for Garnet and Lithium-Ferrite Phase Shifters

    Page(s): 614 - 617
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    Low-cost construction techniques for S-band twin-slab ferrite phase shifters are presented along with an experimental comparison of garnet and lithium-ferrite materials. A 3-bit phase shifter with lithium-ferrite material, which is approximately half the price of garnet material, had a measured loss of 0.4 dB and a peak power handling of 4.5 kW. View full abstract»

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  • Low Cost Design Techniques for Semiconductor Phase Shifters

    Page(s): 675 - 688
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    The design and performance of two microstrip semiconductor phase shifters operating at S band and UHF are described. The S-band diode phase shifter uses thick-film metallization on a 99.5-percent alumina substrate and uses series coupled diodes for the small bits and constant phase frequency switched life bits for the three large bits. The 4-bit UHF phase shifter uses eight p-i-n diodes mounted in a low dielectric constant microstrip circuit and operates at a power level of 8 kW peak, 240 W average, and has an average insertion loss of 0.7 dB. Phase and VSWR distributions on 800 units produced are also given. The characteristics of two new microwave semiconductor switching devices, the field-effect diode (FED) and the resistive gate switch are described. These devices operate with only a voltage change. Design and performance of an SP2T switch and 3-bit phase shifter using the field-effect diode are presented. View full abstract»

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  • Periodically Loaded Nonreciprocal Transmission Lines for Phase-Shifter Applications

    Page(s): 635 - 640
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    Nonreciprocal transmission lines periodically loaded with thin metallic diaphragms are analyzed using the wave transmission matrix approach. An approximate equivalent circuit representation of the diaphragm is proposed and discussed. Using this representation, the differential phase-shift and impedance characteristics of the periodically loaded line are computed for assumed parameters, for "shunt-capacitance" and "shunt-inductance" loading. The range of validity of the approximate results is examined using a certain criterion. The differential phase shift for both capacitive and inductive loading is found to be greater than that of the unloaded line and the results show the same general trends as those previously observed experimentally. View full abstract»

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  • Diode Phase Shifters for Array Antennas

    Page(s): 658 - 674
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    This paper contains considerations for diode phase shifters used for phased array antenna control. The categories are: 1) areas in which ferrite and diode phase shifters differ, 2) diode phase-shifter circuits, 3) the nature and typical performance of p-i-n diodes, 4) the requirements of a driver and a typical circuit, and 5) measured performance of phase shifters in L, S, C, and X bands. View full abstract»

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  • A Catalog of Low Power Loss Parameters and High Power Thresholds for Partially Magnetized Ferrites

    Page(s): 645 - 651
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    The low power loss and high power threshold properties have been measured on a number of candidate ferrite phase-shifting materials. The low power loss is characterized by μ0'', the imaginary part of the diagonal component of the permeability tensor for the completely demagnetized state. μsub 0/'' was measured from 3.0 to 16.8 GHz. The high power properties are characterized by the parallel pump threshold at a bias field correspontig to Hi ≡ 0 and to 4πM ≡ 4πMs. The threshold was measured between 3.0 and 16.8 GHz. For the purposes of computer calculation μ0'' and hcrit were fit to an equation of the form A (γ4πMs / ω)N. Translating μ0'' and hcrit to ΔHeff and ΔHk gives the YIG plus Al as the lowest loss and lowest threshold materials followed by the Gd garnets and MgMn spinels. The Ni spinels are very Iossy. View full abstract»

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  • Microwave Lithium Ferrites: An Overview

    Page(s): 652 - 658
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    Lithium ferrites are discussed and compared with other spinel microwave ferrites and rare earth-iron garnets. Points of comparison are saturation magnetization, temperature performance, hysteresis loop properties, stress sensitivity, insertion loss, power handling capability, resonance linewidth, and cost. The main points of discussion deal with the relative effectiveness of lithium ferrites, nickel ferrites, magnesium ferrites, and garnets as elements employed in latching applications at frequencies in the S, C, X, and Ku bands. A section is devoted to the compositional modifications necessary for: 1) adjusting magnetization, spin-wave line width, coercive force, and magnetic anisotropy; 2) the minimization of stress sensitivity and dielectric loss; and 3) the improvement of microstructural characteristics. View full abstract»

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  • Microwave Characterization of Partially Magnetized Ferrites

    Page(s): 641 - 645
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    In order to assist the microwave engineer in predicting the performance of partially magnetized devices, we have characterized the microwave permeability of partially magnetized materials. The real part of the tensor permeability elements, μ, κ, and μz, depends primarily on the parameters γ4πM/ω and γ4πMs / ω. Empirical formulas have been developed which show the dependence. At frequencies sufficiently below ω = π4πMs, the loss can be characterized by the value of μ'' at 4πM = 0.μ, κ, and μz depend weakly on composition, whereas μ'' (4πM = 0) does depend upon the chemical composition. View full abstract»

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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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