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Microwave Theory and Techniques, IEEE Transactions on

Issue 7  Part 1-2 • Date July 1995

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Displaying Results 1 - 25 of 50
  • Comment on "A field theoretical derivation of TLM" [with reply]

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    For the original article see ibid., vol. 42, no. 9, p.1660-68 (1994). The commenter points out that contrary to what is claimed in the aforementioned paper by M. Krumpholz and P. Russer, former mathematical derivations of the TLM method directly from Maxwell's equations (meeting all requirements of rigor, but less complicated than the paper) have been given. Two examples are cited. In reply the authors clarify what they mean by "direct derivation" and explain how this differs from the cited examples. They emphasize that their derivation is solely based on Maxwell's equations and the method of moments approximation. Thus the physical basis and the mathematical treatment are clearly separated.<> View full abstract»

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  • Comments on "Coaxial probe modeling in waveguides and cavities" [with reply]

    Page(s): 1629 - 1630
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    For the original article see ibid., vol. 40, p.2172-80 (1992). The commenters state that in the aforementioned paper, Liang et al. presented an excellent analysis of a coaxial probe in waveguides and cavities. The compact dyadic Green's function technique was applied there to calculate the electric field. However, they point out some typographical errors of the dyadic Green's function components in the paper which will mislead further investigations. These errors are listed and corrections given. In reply the authors welcome the comments and also point out a further error for which the correct form is given.<> View full abstract»

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  • A monolithic integrated millimeter wave transmitter for automotive applications

    Page(s): 1654 - 1658
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    An integrated transmitter at 80 GHz is presented. This device finds many applications in civil sensor and communication systems, and is employed in automotive applications. The device consists of an IMPATT diode and a slotted patch resonator. The resonator acts simultaneously as an antenna. The resonator impedance seen by the IMPATT diode is calculated by means of a full wave analysis and the matching of the IMPATT diode is investigated using a large signal analysis. The transmitter devices have been fabricated employing a SIMMWIC (silicon millimeter wave integrated circuit) fabrication process and deliver a radiated power of up to 1 mW at 79 GHz. An excellent carrier-to-noise ratio of 81.7 dBc/Hz at an offset of 100 kHz has been achieved. The deviation of the measured values from the theoretically predicted values of frequency and power is -5.9% and -1.5 dB, respectively View full abstract»

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  • A microwave noncontact identification transponder using subharmonic interrogation

    Page(s): 1673 - 1679
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    This paper presents the design and analysis of a novel microwave radio (RF/ID) transponder that has been developed for remote identification of personnel and articles, such as in “wireless key” entry systems. Based on a subharmonically pumped quasi-optical mixer, the transponder is activated by a C-band interrogation beam to upconvert and radiate a digitally modulated identification tone at two X-band frequencies. These response signals are nonharmonically related to the interrogation signal. The frequency conversion process is analyzed using a Volterra series model that includes the effects of self-bias current, coupled with a scattering metric that is directly useful in radio link calculations View full abstract»

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  • Input impedance of a probe-excited semi-infinite rectangular waveguide with arbitrary multilayered loads. I. Dyadic Green's functions

    Page(s): 1559 - 1566
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    This paper presents both the electric and the magnetic types of dyadic Green's functions defined for electromagnetic fields due to electric and magnetic current sources in a semi-infinite rectangular waveguide filled with arbitrary multilayered media. Applying the principle of scattering superposition, the dyadic Green's functions in each of the multiple loads are constructed in general for such EM current sources located in an arbitrary layer of the waveguide. Analytical expressions of the scattering dyadic Green's functions' coefficients are obtained in terms of transmission matrices. To demonstrate how the method presented is used and how the results are obtained for some special cases, a semi-infinite rectangular waveguide with one load is considered. The dyadic Green's functions and their coefficients in such a case are derived in closed form by reducing the general formulae of the dyadic Green's functions for the arbitrary multiple case to those for the special case concerned. Further comparison of the dyadic Green's functions obtained here with previous publications shows good agreement, demonstrating the applicability of the results presented here View full abstract»

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  • On the theory of discrete TLM Green's functions in three-dimensional TLM

    Page(s): 1472 - 1483
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    The response to a wave pulse incident on the boundary of a certain spatial domain may be represented by discrete TLM Green's functions. On the other hand, the response to a localized electromagnetic excitation at the boundary of a certain spatial domain may be calculated directly from Maxwell's equations and be represented by analytic TLM Green's functions. For low frequencies and small wave numbers, the analytic TLM Green's functions coincide with the discrete TLM Green's functions. Applying the analytic TLM Green's functions in the absorbing boundary condition at the boundary to the open half-space reduces the computational effort considerably when compared with the application of the discrete TLM Green's functions View full abstract»

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  • Simultaneous AM-AM/AM-PM distortion measurements of microwave transistors using active load-pull and six-port techniques

    Page(s): 1584 - 1588
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    A programmable active load-pull measurement system using two six-port reflectometers and three passive two-port standards has been developed to obtain load-pull contours of the transistor's input-output phase shift variations over a wide dynamic range of the input power. The output power, gain, power-added efficiency, and phase shift are measured simultaneously at the transistor's input and output reference planes. The phase distortion versus input power, φ~Pin, and the AM-PM conversion coefficient at various power levels, k~Pin, are obtained for different load impedances by post-measurement calculations. A NE8001 MESFET is tested at f=1.7 GHz for the class A operation. The experimental results are also given View full abstract»

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  • Novel techniques for millimeter-wave packages

    Page(s): 1516 - 1523
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    A new millimeter-wave package architecture with supporting electrical, mechanical and material science experiment and analysis is presented. This package is well suited for discrete devices, monolithic microwave integrated circuits (MMIC's) and multichip module (MCM) applications. It has low-loss wideband RF transitions which are necessary to overcome manufacturing tolerances leading to lower per unit cost. Potential applications of this new packaging architecture which go beyond the standard requirements of device protection include integration of antennas, compatibility to photonic networks and direct transitions to waveguide systems. Techniques for electromagnetic analysis, thermal control and hermetic sealing were explored. Three dimensional electromagnetic analysis was performed using a finite-difference time-domain (FDTD) algorithm and experimentally verified for millimeter-wave package input and output transitions. New multi-material system concepts (AlN, Cu, and diamond thin films) which allow excellent surface finishes to be achieved with enhanced thermal management have been investigated. A new approach utilizing block copolymer coatings was employed to hermetically seal packages which met MIL STD-883 View full abstract»

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  • Numerical analysis of printed strip dipole hyperthermia applicators

    Page(s): 1502 - 1507
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    The performance of a planar printed strip dipole hyperthermia applicator is simulated using a computer. The applicator is modeled using an exact integral equation formulation, and Galerkin's method is used to obtain the approximate current distribution on the dipole antenna. These currents are then used to compute the input impedance and heating pattern for the applicator. The computer model is used to investigate, and eliminate, the problem of “hot-spots” in the fat layer View full abstract»

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  • Coplanar waveguide bandpass filter-a ribbon-of-brick-wall design

    Page(s): 1589 - 1596
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (624 KB)  

    This paper proposes a novel ribbon-of-brick-wall design of the coplanar waveguide bandpass filter which is built from cascading several sections of quarter wavelength open-end series stubs. The design originates from modeling the series stub as a system of two asymmetrically coupled transmission lines, which is then made equivalent to a basic filter element of admittance inverter. The relationship between the parameters of the coupled transmission lines and the admittance inverter is derived and the design charts are provided for the convenience of the designers. Systematic procedure is established to design the Chebyshev filter, which is also fabricated and measured. In addition, the quasistatic equivalent lumped circuit models of the discontinuities formed between two sections are evaluated and incorporated into the circuit simulation to get better prediction for the filter performance. The good agreement between simulation results and experimental data justifies the design procedure and validates the present analysis approach View full abstract»

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  • An L-band ultra-low-power-consumption monolithic low-noise amplifier

    Page(s): 1745 - 1750
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    A low-power consumption variable-gain low-noise amplifier (LNA) is demonstrated. To achieve low noise, low distortion, and low power consumption simultaneously, a cascode connection between an enhancement-mode GaAs MESFET (EFET) and a depletion-mode GaAs MESFET (DFET) is employed. The EFET is superior to the DFET in its gain and noise figure performance while the DFET offers good intermodulation distortion performance. The advantages of both types of FET's are combined in the developed LNA. It shows excellent performance with an NF of 2.0 dB, a gain of 12.2 dB, and an IP3 of 5.1 dBm at 1.9 GHz. The demonstrated performance satisfies the specifications of the Japanese Personal Handyphone System even at the ultra-low power consumption of 2.0 mW View full abstract»

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  • Accurate study of Q-factor of resonator by a finite-difference time-domain method

    Page(s): 1524 - 1529
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    This paper describes the application of the finite-difference time-domain method to find the resonators' Q-factors. There are some techniques which can be used to reach it. One way is to directly compute the power loss using the surface impedance boundary condition (SIBC). The other is to incorporate the perturbation techniques to calculate the Q-value. The rectangular and cylindrical cavities have been studied by these methods. A number of superconductor-sapphire microwave resonators with extra high Q-values have been studied. The results are very good in accuracy View full abstract»

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  • A new large-signal AlGaAs/GaAs HBT model including self-heating effects, with corresponding parameter-extraction procedure

    Page(s): 1433 - 1445
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    Accurate modelling of the microwave large-signal characteristics of AlGaAs/GaAs Heterojunction Bipolar Transistors (HBT's) is extremely useful for microwave power applications of the device. This paper presents a new type of HBT large-signal model which is valid for dc, small-signal and large-signal ac modes of operation. The model may be used over a wide range of operating conditions and includes allowance for self-heating effects which are very important for HBT's. Through the use of several novel features, the proposed approach is differentiated from the traditional Ebers-Moll or Gummel-Poon BJT representations. The new model is accompanied by a very simple parameter extraction process requiring only a series of conventional dc and multi-bias point small-signal S-parameter measurements. Finally, the model is validated by independent power sweep measurements on HBT's from two different manufacturers View full abstract»

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  • Modulation/microwave integrated digital wireless developments

    Page(s): 1715 - 1732
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    Simultaneous study and joint optimization of digital modulation techniques and of microwave components, presented in this paper, lead to spectrally efficient, high capacity, fast transmission, and throughput rate wireless systems. The choice of a particular modulation/demodulation (modem) technique has a major impact on the overall microwave system design, transceiver architecture and on the choice of all intermediate frequency (IF) as well as radio frequency (RF) component specifications. The performances of the most frequently used digital modulation techniques, including π/4-DQPSK, conventional BPSK, DQPSK, GMSK, GFSK, 4FSK, and FQPSK systems are compared. Study of crosscorrelated quadrature modulated GMSK systems used in GSM, PCS-1900, and other standards indicate that the subject technologies applied to GMSK improve the performance of these systems. We demonstrate that with the patented family of digitally modulated Feher's FQPSK systems, the power efficiency of conventional QPSK systems, which require linear microwave amplifiers, can be increased by about 300%, and the spectral efficiency of standardized nonlinearly amplified microwave integrated circuit GMSK systems can be increased by 60-200%. Similar advantages are obtained with our new FBPSK over BPSK modulated systems View full abstract»

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  • Characterization of cylindrical microstriplines mounted inside a ground cylindrical surface

    Page(s): 1607 - 1610
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    A full-wave analysis for the frequency-dependent characteristics of a cylindrical microstripline mounted inside a ground cylindrical surface is presented. Numerical results of the effective dielectric constant and characteristic impedance for various microstripline parameters are calculated and analyzed. Strong dispersive behavior is observed for such cylindrical microstriplines View full abstract»

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  • Packet communication ultra-small aperture terminal system for the Hokkaido Integrated Telecommunication network

    Page(s): 1692 - 1698
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    Three aspects of a new minimum cost, high reliability system strategy for the Hokkaido Integrated Telecommunication (HIT) network, in which real time operation is not demanded, are examined. These are: (1) a packet communication ultra-small aperture terminal (PC-USAT) system, which contains a method for overcoming the satellite link's rain attenuation discontinuities; (2) an optimum rain margin technique and the 14/12-GHz band rain, snow attenuation, and site diversity (SD) experiments; and (3) a low-bit-rate medical information and still picture simultaneous transmission system View full abstract»

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  • Forward-looking automotive radar using a W-band single-chip transceiver

    Page(s): 1659 - 1668
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    A prototype W-band all-weather automotive radar based on a single-chip 0.1-μm AlGaAs-InGaAs-GaAs HEMT transceiver has been developed. This radar has the features of simple architecture and small size, with adequate performance. Owing to the maturity of HEMT MMIC technology, this radar is potentially low cost to implement in personal vehicles. The prototype radar used for autonomous intelligent cruise control in a passenger car is presented in this paper. The MMIC development, together with the radar system design, is also addressed View full abstract»

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  • Miniature microwave filters for communication systems

    Page(s): 1751 - 1757
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    This paper presents new developments in miniature integrated microwave filters suitable for application in mobile communication handsets, wireless LAN's and microwave fixed links. Recent measured results for active microwave filters are presented with emphasis on their nonlinear behavior. The use of high permittivity ceramic substrates in parallel plate TEM mode stripline filters is described and recent measured results are presented for a prototype 2-GHz filter occupying a volume of 0.5-cubic centimeters. E-Plane filters for millimeter wave applications are discussed and measured results are presented for a novel E-Plane filter with asymmetric frequency response which was realized in a planar structure. Finally, a new type of ceramic loaded E-Plane filter is proposed View full abstract»

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  • Rigorous quasi-TEM analysis of multiconductor transmission lines in bi-isotropic media. Part II. Numerical solution for layered media

    Page(s): 1416 - 1423
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (532 KB)  

    For part I see ibid., vol.43, no.7, pp.1409-15 (1995). An integral equation technique is used to determine the circuit parameters of the nonreciprocal and nonsymmetrical set of transmission lines that describe a multiconductor line in a layered bi-isotropic background in the quasi-TEM approximation. The integral equation is solved with the method of moments and pointmatching technique. The integrations arising in the problem are handled carefully to allow a fast and accurate implementation. The conductors have an arbitrary cross-section consisting of straight and circularly curved segments. At the edges of the conductors the singular behavior of the surface charge density and surface current density is explicitly taken into account View full abstract»

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  • A new adaptive double envelope feedback (ADEF) linearizer for solid state power amplifiers

    Page(s): 1508 - 1515
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    A new adaptive double envelope feedback (ADEF) linearizer using a voltage-controlled phase-shifter for predistortion purpose and a dynamic gate bias for gain stabilization purpose has been developed and implemented on a two-watt MESFET amplifier. A two-tone test around 1.6 GHz shows average in-band intermodulation product below -40 dBc up to saturation with a power-added efficiency of 40% at the 1-dB compression point. Validation of the adaptive features of the ADEF technique is carried out with respect to carrier frequency, temperature, two-tone amplitude offset and spacing. In addition, a new formula, which directly relates the third order intermodulation level to the AM/AM and AM/PM distortion coefficients of solid state nonlinear amplifiers is proposed and its accuracy is assessed using both simulation and experimental results View full abstract»

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  • Dielectric resonator-microstrip interactive circuit analysis and design using integral equation techniques

    Page(s): 1446 - 1452
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    Dielectric resonators (DR's) are widely used in microwave/millimeter-wave technologies. In this paper, the coupling between a dielectric resonator and a microstrip circuit is studied. To analyze this problem, an integral equation is developed for the current distribution on the microstrip circuit. The Green's function used in this integral equation is the Green's function of the field in a layered medium modified by adding a term corresponding to the DR-scattered field. This field is produced by equivalent electric and magnetic sources assumed to be on the DR's surface. An efficient numerical method is applied which gives an approximation of the field near the resonant frequency of the DR. The results clearly show the effect of the DR on the microstrip circuit's current distribution and provides a thorough insight into the coupling mechanism. The coupling parameters can be estimated from the current distribution. The efficiency of the method as well as its flexibility in dealing with a general configuration of the DR and microstrip circuit makes it promising for CAD applications View full abstract»

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  • General formulas for the method of lines in cylindrical coordinates

    Page(s): 1617 - 1620
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    General formulas are given for the method of lines in cylindrical coordinates and angular discretization. They describe the transfer of the fields from one boundary of a cylindrical layer to another in a multilayered structure. With these formulas, programming can be accomplished without performing additional analysis View full abstract»

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  • Combined differential and common-mode scattering parameters: theory and simulation

    Page(s): 1530 - 1539
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    A theory for combined differential and common-mode normalized power waves is developed in terms of even and odd mode impedances and propagation constants for a microwave coupled line system. These are related to even and odd-mode terminal currents and voltages. Generalized s-parameters of a two-port are developed for waves propagating in several coupled modes. The two-port s-parameters form a 4-by-4 matrix containing differential-mode, common-mode, and cross-mode s-parameters. A special case of the theory allows the use of uncoupled transmission lines to measure the coupled-mode waves. Simulations verify the concept of these mixed-mode s-parameters, and demonstrate conversion from mode to mode for asymmetric microwave structures View full abstract»

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  • New MMIC's for tuners in multichannel video distribution systems using optical fiber networks

    Page(s): 1686 - 1691
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    New MMIC's have been developed for an ultra-broadband FM video tuner in a multi-channel video distribution system using optical fiber networks. The MMIC's provide both frequency synthesis and up-conversion. They are integrated on two GaAs MMIC chips and one Si LSI chip. The chips are mounted in a flat package to form a tunable block up converter, By combining the MMIC's with currently available consumer product type components, a low cost FM video tuner with a 2 GHz tuning bandwidth was achieved in hardware. Successful tuning performance is obtained over the whole tuning frequency range View full abstract»

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  • Attenuation of the parasitic modes in a shielded microstrip line by coating resistive films on the substrate

    Page(s): 1610 - 1613
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    In this paper, propagation characteristics of even-symmetric hybrid modes in a waveguide-shielded microstrip line with the presence of the resistive films affixed to the two sides of the center strip is investigated. The method of lines with modifications concerning the inhomogeneity of the surface between the air and substrate layers is used for analysis. After a validity check of the analysis by considering two special structures, i.e., a microstrip line (Rm=∞) and a coplanar waveguide (Rm=0), the resistance Rm and the width Wm of the film are varied to see the influence on the propagation and attenuation constants of the dominant mode as well as the higher-order (parasitic) modes. Optimal combinations of the resistance and the width are found so that the resistive film has the largest attenuating effect on the higher-order modes but has no interference with the dominant one 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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