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Microwave Theory and Techniques, IEEE Transactions on

Issue 5 • Date May 1993

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Displaying Results 1 - 25 of 29
  • Comments on "A procedure defining behavior of weight functions near the edge for best convergence using the Galerkin method" by P.S. Fridberg and I.M. Yakover

    Publication Year: 1993 , Page(s): 900 - 901
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (167 KB)  

    The commenters remark on the importance and timeliness of the procedure presented in the above-titled paper by P.S. Fridberg and I.M. Yakover (see ibid., vol.40, no.8, p.1661-1667, 1992). They also point out a global optimization procedure of the coordinate functions used in connection with the Galerkin, Rayleigh-Ritz or the Kantorovich method, based on Lord Rayleigh's optimization procedure.<> View full abstract»

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  • A transformed symmetrical condensed node for the effective TLM analysis of guided wave problems

    Publication Year: 1993 , Page(s): 820 - 823
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (352 KB)  

    A transmission line matrix (TLM) algorithm for the effective solution of arbitrary guided wave problems is proposed. The algorithm uses an appropriately transformed symmetrical condensed node (SCN) introduced herein. In comparison with the previous SCN TLM formulation for the analysis of guiding structures, the approach maintains equivalent accuracy and generality while providing a 50% gain in terms of required computer memory and time. The advantages of the new algorithm are verified by means of several examples, including full-wave analysis of waveguides filled with anisotropic and lossy media View full abstract»

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  • On the use of Levin's T-transform in accelerating the summation of series representing the free-space periodic Green's functions

    Publication Year: 1993 , Page(s): 884 - 886
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (240 KB)  

    The Levin's T-transform is shown to accelerate the summation of slowly converging series. This is illustrated by application of the transform to the series representing the free-space periodic Green's functions involving a single and double infinite summation. Numerical results indicate that the transform converges more rapidly than a direct summation of the series. Thus, it provides considerable savings in computation time View full abstract»

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  • New equivalent networks with simple closed-form expressions for open and slit-coupled E-plane tee junctions

    Publication Year: 1993 , Page(s): 839 - 847
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (776 KB)  

    Analytical expressions are presented for the elements of new equivalent networks for open and slit-coupled E-plane tee junctions. The expressions are in simple closed form, and their accuracy is verified by comparisons with measurements. Physically based stored power considerations are also developed in context to indicate how appropriate changes in the geometry can be taken into account View full abstract»

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  • Analysis of slow-wave transmission lines on multi-layered semiconductor structures including conductor loss

    Publication Year: 1993 , Page(s): 824 - 829
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (468 KB)  

    Metal lines on semiconductor devices and circuits sometimes show slow-wave phenomena. To determine signal transmission characteristics along the lines, the typical assumption that metal is perfectly conducting is not always valid. A simple and accurate means is used here to include metallic loss in spectral domain analysis of planar transmission lines built on multilayer semiconducting media. Experimental results with a modulation-doped field-effect transistor (MODFET) structure and comparison with the calculations are presented View full abstract»

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  • Computer-aided design of a singly-matched (S-M) multiplexer with a common junction

    Publication Year: 1993 , Page(s): 886 - 890
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (384 KB)  

    Formulas based on scattering parameters are presented for the design of a multiplexer composed of n-1 channel equalizers connected either in parallel or in series at a common junction with a 1-Ω resistive generator and n-1 channel complex loads. It is shown as the singly-matched (S-M) multiplexer. A two-stage computer-aided design (CAD) approach is developed for the S-M multiplexer. A design example of a three-channel S-M multiplexer including the designs of three individual S-M channel equalizers is given to demonstrate the approach View full abstract»

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  • Varactor-tunable uniplanar ring resonators

    Publication Year: 1993 , Page(s): 760 - 766
    Cited by:  Papers (15)  |  Patents (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (544 KB)  

    Slotline and CPW ring resonators are introduced and integrated with varactor diodes to create electronically tunable uniplanar ring resonators. Varactors electronically tune the second resonant mode of the slotline ring over a 23% bandwidth from 3.03 to 3.83 GHz with a 4.5±1.5 dB variation in insertion loss. Similarly, a CPW ring resonator was tuned over a 22% bandwidth from 2.88 to 3.59 GHz. Both resonators offer the ground plane and center conductor on the same side of the substrate to allow easy series or shunt insertion of solid-state devices. DC biasing is naturally integrated in the slotline structure and straightforward in CPW. Monolithic implementation of these resonators would not require via holes to ground solid-state devices which should reduce processing complexity and increase production yields View full abstract»

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  • Field analysis of dielectric-loaded lens applicator for microwave hyperthermia

    Publication Year: 1993 , Page(s): 792 - 796
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (344 KB)  

    A dielectric-loaded waveguide applicator for microwave hyperthermia is analyzed. The phase constant in the waveguide is determined from the numerical solution of the characteristic equation. The field pattern in human muscle which is produced by the applicator is determined by using the Kirchhoff-Huygens principle. The field focusing effect is dependent on the properties of the low permittivity dielectric slab centered in the water-filled waveguide. The greatest field enhancement is found to occur when the slab is 75-mm wide for a 150-mm×100 mm waveguide at 430 MHz View full abstract»

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  • Accurate analysis and design of millimeter wave mixers

    Publication Year: 1993 , Page(s): 870 - 873
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (460 KB)  

    The present study is based on the method introduced by B. Shuppert (1986) for nonlinear analysis of mixers, but it differs in the linear part. In particular, the circuit characterization of the mixer harmonics is emphasized, removing the usual approximation of matched terminations and employing models that effectively represent network characteristics in the microwave and millimeter wave domain. This goal is achieved through the accurate knowledge of the various components used in the mixer and the use of accurate equivalent circuits. In order to validate the model, two subharmonic mixers operating at K-band (18-26 GHz) were realized. Reasonable agreement between theoretical and experimental results is achieved View full abstract»

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  • Automatic generation of starting values for the simulation of microwave oscillators by frequency domain techniques

    Publication Year: 1993 , Page(s): 809 - 813
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (448 KB)  

    A new approach to the start-up problem inherent to the large-signal analysis of autonomous circuits in the frequency domain is presented. By insertion of a simple network, depending on one parameter, the oscillator is damped to the stability limit where a linear analysis yields good results. The steady state of the undamped oscillator is then obtained by a continuation method corresponding to the successive removal of the damping network. With this procedure the degenerate solution may be excluded in a straightforward manner View full abstract»

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  • Breakdown in the inhomogeneous electric field of a microwave transmit-receive switch

    Publication Year: 1993 , Page(s): 879 - 881
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (248 KB)  

    A detailed analytical investigation is made of the threshold for breakdown in microwave transmit-receive switches. The geometry of the keep alive contacts of the switch is modeled as a double cone configuration, and the subsequent diffusion equation for the electron density in the presence of strongly inhomogeneous ionization is solved analytically. Predictions for the breakdown power are found to be in agreement with previously presented experimental results View full abstract»

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  • Electromagnetic scattering from an infinite circular metallic cylinder coated by an elliptic dielectric one

    Publication Year: 1993 , Page(s): 862 - 869
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (432 KB)  

    The scattering from an infinite, circular, perfectly conducting cylinder coated by an elliptic dielectric cylinder is considered. The electromagnetic field is expressed in terms of both circular and elliptical cylindrical wave functions, which are connected with one another by well-known expansion formulas. In the special case of small h=ka/2 (a is the interfocal distance of the elliptic dielectric and k its wavenumber), exact, closed-form expressions of the form S(h)=S(0)[1+gh 2+O(h4)] are obtained for the scattered field and the various scattering cross sections. Both polarizations are considered for normal incidence. Graphical results for various values of the parameters are given View full abstract»

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  • Calibration and applications of polarization-correlating radiometers

    Publication Year: 1993 , Page(s): 767 - 773
    Cited by:  Papers (32)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (564 KB)  

    Hardware and associated software for nonmechanical rotation of the polarization basis of a dual linearly polarized cross-correlating radiometer are demonstrated. The technique requires precise measurement of two orthogonal-mode antenna temperatures along with cross-correlation of the two orthogonal-mode field amplitudes. Collectively, these are the first three Stokes parameters. A polarized blackbody load was developed for accurate calibration of the orthogonal-mode and cross-correlating channels. Using the hardware, rotation of the radiometer antenna's polarization basis by a matrix transformation was demonstrated by 91.65 GHz near-Brewster-angle scans of a polarizing water surface. The experimental results demonstrate the viability of the rotation technique and suggest practical calibration schemes for airborne and spaceborne polarimetric radiometers. Application of the rotation technique in mechanically scanned polarization-sensitive imaging radiometers will eliminate polarization coupling inherent in conventional fixed-feed dual-polarization scanner designs View full abstract»

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  • An AlGaAs/InGaAs pseudomorphic high electron mobility transistor with improved breakdown voltage for X- and Ku-band power applications

    Publication Year: 1993 , Page(s): 752 - 759
    Cited by:  Papers (39)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (740 KB)  

    The authors determined that RF drain current degradation is responsible for the poor power performance of wide-recessed pseudomorphic high-electron-mobility transistors (PHEMTs). A model based on surface states was proposed to explain this phenomenon, which then led to the use of charge-screen layers and a double-recessed gate process to suppress surface effects. Combined, these two modifications increased the device's gate-drain reverse breakdown voltage without causing a degradation in the transistor's RF drain current. This allowed the simultaneous achievement of high power-added efficiency and high power density which established a new performance record for power PHEMTs at X- and Ku-bands. Delay time analysis of single- and double-recessed PHEMTs revealed that the benefit of a larger breakdown voltage in the latter device design came at the cost of a larger drain delay time. Drain delay accounted for 45% of the total delay when the 0.35-μm double-recessed PHEMT was biased at Vds=6 V View full abstract»

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  • Modelling multiple discontinuities in rectangular waveguide partially filled with non-reciprocal ferrites

    Publication Year: 1993 , Page(s): 797 - 802
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (436 KB)  

    This work analyzes multiple 3D discontinuities between rectangular ferrite-loaded waveguides. Each uniform section of waveguide is analyzed by means of Schelkunoff's method with improved convergence. Combining this method with the mode matching method allows the analysis of multiple discontinuities to be simplified. The theoretical results obtained in this way agree quite well with measurements View full abstract»

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  • Design and performance of clock recovery GaAs ICs for high-speed optical communication systems

    Publication Year: 1993 , Page(s): 745 - 751
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (524 KB)  

    Design and performance of clock-recovery GaAs ICs are presented. Four kinds of ICs were developed: a limiting amplifier, a tuning amplifier, a rectifier, and a differentiator. The cascaded limiting amplifier together with a tuning amplifier achieved a 58-dB gain and a 10-degree phase deviation with 20-dB input dynamic range at 10 GHz. A clock-recovery circuit successfully extracts a low-jitter 10-GHz clock signal of 1-dBm constant power from 10-Gb/s NRZ pseudorandom bit streams using a pulse pattern generator View full abstract»

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  • A design method for lumped broadband MMIC matching networks with semiuniform frequency-dependent losses

    Publication Year: 1993 , Page(s): 873 - 876
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (320 KB)  

    A design method for broadband MMIC matching networks which consist of lumped inductors and capacitors is presented. Based on a fictitious transformation between the lossy network and the lossless one, the transducer power gain (TPG) of the lossy network is calculated using impedance matrix and transmission parameter matrix methods. Then, on the basis of the result of TPG optimization, the matching network can be synthesized. Since only the complexity of the matching network needs to be specified, the advantage of the real frequency technique of B.S. Yarman and H.J. Carlin (1982) is retained. In this design procedure the frequency-dependent losses of lumped elements can be considered. Thus the actual gain response tends to coincide with the desired performance more than when the element losses are neglected. An example is given to show the application of the method to broadband GaAs FET amplifier design View full abstract»

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  • The introduction of surface resistance in the three-dimensional finite-difference method in frequency domain

    Publication Year: 1993 , Page(s): 893 - 895
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (264 KB)  

    A full-wave treatment of lossy three-dimensional structures using the finite-difference method in the frequency domain is presented. This accounts for both dielectric and conductor losses. By the introduction of a surface resistance, the effect of conductor losses and surface roughness can be modeled very efficiently. The modifications of the finite-difference-frequency-domain (FDFD) algorithm are presented. Comparisons between the conventional approach using elementary cells with finite conductivity and this new discretization method with surface current cells are given, and the advantages and limitations of the surface current model are shown View full abstract»

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  • TM scattering from a slit in a thick conducting screen: revisited

    Publication Year: 1993 , Page(s): 895 - 899
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (296 KB)  

    TM plane wave scattering from a slit in a thick conducting screen is examined. A Fourier transform technique is employed to express the scattered field in the spectral domain and the boundary conditions are enforced to obtain simultaneous equations for the transmitted field inside the thick conducting screen. The simultaneous equations are solved to represent the transmitted and scattered fields in series forms. Approximate series solutions for scattering and transmission are obtained in closed-forms which are valid for high-frequency scattering regime View full abstract»

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  • Cut-off and phase constants of partially filled axially magnetized, gyromagnetic waveguides using finite elements

    Publication Year: 1993 , Page(s): 803 - 808
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (436 KB)  

    A three-component vector finite-element formulation for modeling the propagation characteristics of partially filled, axially magnetized, gyromagnetic waveguides is described. Covariant-projection elements have been used to avoid spurious modes, and periodic boundary conditions have been implemented to improve numerical efficiency. The classic quadratic functional derived from the vector, curlcurl, magnetic field equation is suited to evaluating the cut-off planes of gyrotropic waveguides. A known field transformation is used to reformulate the functional in a form convenient for calculating phase constants. Cut-off and phase constant solutions are presented for both fully and partially filled, longitudinally magnetized, ferrite-loaded waveguides View full abstract»

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  • X-band low phase distortion MMIC power limiter

    Publication Year: 1993 , Page(s): 876 - 879
    Cited by:  Papers (3)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (316 KB)  

    Describes the design and performance of an 8-GHz MMIC (monolithic microwave integrated circuit) MESFET (metal-semiconductor FET) power limiter. This limiter incorporates a special gate biasing scheme and makes use of appropriate load conditions which reduce the unexpected phase variations experienced by the signal through the device. Measured performances (phase variations less than 8 over a 22-dB input power range) are found to be in agreement with the theoretical ones obtained from large signal simulations View full abstract»

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  • Bistatic frequency-swept microwave imaging: Principle, methodology and experimental results

    Publication Year: 1993 , Page(s): 855 - 861
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (596 KB)  

    The basic principle, methodology, and experimental results for frequency-swept microwave imaging of continuous shape conducting and discrete line objects in a bistatic scattering arrangement are presented. The theoretical analysis is developed under the assumptions of plane wave illumination and physical optics approximation. The measurement system and calibration procedures are implemented based on plane wave spectrum analysis. Images of three different types of scattering objects reconstructed from the experimental data obtained in the frequency range 7.5-12.5 GHz are shown to be in good agreement with the scattering object geometries. The results demonstrate that this bistatic frequency-swept microwave imaging system has potential as a cost-effective tool for remote sensing, imaging radar, and nondestructive evaluation View full abstract»

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  • Impedance, attenuation and power-handling characteristics of double L-septa waveguides

    Publication Year: 1993 , Page(s): 881 - 884
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (340 KB)  

    Rectangular waveguides with two L-shaped septa attached to the broad walls in antipodal configuration have been shown theoretically by the authors (see ibid. vol.40, no.4, p.777-781, 1992) to be an improved variant of the double T-septa guide having larger cut-off wavelength and broader bandwidth of the dominant TE mode. Numerical data on the attenuation, impedance, and power handling capability of this new type of broadband guide are presented as additional design information View full abstract»

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  • Resonance in a superstrate-loaded cylindrical-rectangular microstrip structure

    Publication Year: 1993 , Page(s): 814 - 819
    Cited by:  Papers (20)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (424 KB)  

    The complex resonant frequencies of the cylindrical-rectangular microstrip structure loaded with a dielectric superstrate layer is studied using a rigorous full-wave analysis, and the numerical results are obtained using the Galerkin moment method calculation. The numerical convergence for the selected sinusoidal basis functions with and without the edge singularity condition is also discussed. Numerical results for the dependence of the real and imaginary parts of the complex resonant frequencies on the superstrate permittivity and thickness are calculated and analyzed, and are compared with those obtained for the planar microstrip structure View full abstract»

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  • Negative differential resistance (NDR) frequency conversion with gain

    Publication Year: 1993 , Page(s): 890 - 893
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (360 KB)  

    The dependence of the conductance of negative differential resistance (NDR) devices in the presence of an RF signal of varying amplitude has been theoretically analyzed. Variable absolute negative conductance has been observed in both unbiased resonant tunneling devices and biased tunnel diode when the applied pump power is within the correct range. The theoretical observation of the dependence of the DC conductance of the NDR devices on the power level of the applied pump signal is supported by the experimental results. Absolute negative conductance of NDR devices provides the possibility of oscillation and harmonic oscillation up to the cut-off frequency of the device. Biased oscillators and self-oscillating frequency multipliers have been experimentally demonstrated using a tunnel diode. Unbiased oscillators have also been successfully realized with two back-to-back connected tunnel diodes which exhibit an anti-symmetrical I-V characteristic 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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