Showing papers in "IEEE Microwave and Guided Wave Letters in 1994"
Cray1
TL;DR: In this article, a novel absorbing boundary condition (ABC) for FD-TD meshes in two dimensions, called the "perfectly matched layer (PML) for the absorption of electromagnetic waves", was proposed.
Abstract: Berenger recently published a novel absorbing boundary condition (ABC) for FD-TD meshes in two dimensions, claiming orders-of-magnitude improved performance relative to any earlier technique. This approach, which he calls the "perfectly matched layer (PML) for the absorption of electromagnetic waves", creates a nonphysical absorber adjacent to the outer grid boundary that has a wave impedance independent of the angle of incidence and frequency of outgoing scattered waves. This paper verifies Berenger's strong claims for PML for 2-D FD-TD grids and extends and verifies PML for 3-D FD-TD grids. Indeed, PML is >40 db more accurate than second-order Mur (1981), and PML works just as well in 3-D as it does in 2-D. It should have a major impact upon the entire FD-TD modeling community, leading to new possibilities for high-accuracy simulations especially for low-observable aerospace targets. >
408 citations
TL;DR: In this article, a general approach for including lumped circuit elements in a finite difference time domain (FDTD) solution of Maxwell's equations is presented, which allows the direct access to SPICE to model the lumped circuits, while the full 3-dimensional solution to Maxwell's equation provides the crosstalk and dispersive properties of the microstrips and striplines in the circuit.
Abstract: A general approach for including lumped circuit elements in a finite difference time domain (FDTD) solution of Maxwell's equations is presented. The methodology allows the direct access to SPICE to model the lumped circuits, while the full 3-dimensional solution to Maxwell's equations provides the crosstalk and dispersive properties of the microstrips and striplines in the circuit. >
168 citations
TL;DR: In this article, the authors measured the radiation efficiency of dielectric resonator antennas in the dominant hybrid (HE/sub 11/spl delta) mode and showed that the conduction losses are quite small.
Abstract: Radiation efficiency (due to conduction and dielectric losses) of dielectric resonator antennas has been measured. Results show that for dielectric resonators placed directly on a metallic plane, the conduction losses are quite small. A radiation efficiency of >98% has been measured for dielectric resonator antennas operated in the dominant hybrid (HE/sub 11/spl delta//) mode. Theoretical considerations show scope of further improvement in the radiation efficiency by choosing optimum resonator parameters. >
127 citations
TL;DR: In this article, the Berenger perfectly matched layer (PML) absorbing boundary condition is applied to terminate both perfect electrically conducting (PEC) and dielectric waveguides in two dimensions.
Abstract: A new method for ultrawideband termination of waveguides in finite-difference time-domain (FD-TD) grids is presented. The Berenger perfectly matched layer (PML) absorbing boundary condition is applied to terminate both perfect electrically conducting (PEC) and dielectric waveguides in two dimensions. Reflections of less than -75 dB are obtained over the entire propagation regime. Evidence is presented that the PML ABC is effective even for the evanescent energy present below cutoff in PEC waveguides and the multimode propagation present in dielectric waveguides. >
103 citations
TL;DR: In this article, a relatively broadband quasi-optical amplifier cell and 4/spl times/4 array using folded-slot antennas, suitable for monolithic power combining, is presented.
Abstract: Active antennas on semiconductor substrates often suffer limited bandwidth. We report on a relatively broadband quasi-optical amplifier cell and 4/spl times/4 array using folded-slot antennas, suitable for monolithic power combining. Two orthogonally polarized CPW-fed folded slots are coupled to the input and output ports of a simple resistive feedback MESFET amplifier. The peak effective isotropic power gain in the transmission mode is 11 dB @ 4.3 GHz with 10% bandwidth for the single cell, a factor-of-ten improvement in bandwidth over a similar amplifier cell using patch antennas, and 32 dB @ 4.24 GHz with 8% bandwidth for the array. >
93 citations
TL;DR: A general stability condition has been derived for the WETD(/spl Theta/) method of which the central and backward differences are special cases corresponding to /spl TheTA/=1 and /spl theta/=0, respectively.
Abstract: A family of finite element time-domain methods, WETD(/spl Theta/), is derived to solve the time-varying Maxwell's equations The proposed methodology is based upon the application of the Faedo-Galerkin procedure and the use of the Whitney 1-forms as bases to result in an ordinary differential equation in time for the electric field Moreover, the resultant ordinary differential equation is solved by employing central and/or backward difference approximations Since the WETD methods presented here are used in conjunction with tetrahedral finite element meshes, it imposes no limitations on the problem geometry Also, in this contribution, a general stability condition has been derived for the WETD(/spl Theta/) method of which the central and backward differences are special cases corresponding to /spl Theta/=1 and /spl Theta/=0, respectively >
79 citations
TL;DR: This paper describes an implementation of the finite-difference time-domain calculations using PVM [Parallel Virtual Machine] 3.2 and a cluster of workstations for a test problem involving a three-dimensional rectangular cavity and demonstrates the potential of parallel distributed computing for FDTD calculations in electromagnetics.
Abstract: This paper describes an implementation of the finite-difference time-domain (FDTD) calculations using PVM [Parallel Virtual Machine] 3.2 and a cluster of workstations for a test problem involving a three-dimensional rectangular cavity. It is found that the speedup factors achieved in FDTD calculations can approach the maximum values for large problem sizes if the computation-to-communication ratios are maintained at values significantly greater than unity. It is also found that in order to achieve linear speedups, the problem sizes should be increased with the number of processors while adequate computation-to-communication ratios are maintained in the individual processors. The results demonstrate the potential of parallel distributed computing for FDTD calculations in electromagnetics. >
65 citations
TL;DR: In this article, a more efficient FDTD algorithm is introduced for the analysis of structures involving magnetized ferrites, and a critical issue of time and space synchronism ensuring second order accuracy is discussed.
Abstract: A more efficient FDTD algorithm is introduced for the analysis of structures involving magnetized ferrites. A critical issue of time and space synchronism ensuring second order accuracy is discussed, and a method to provide it based on extrapolation rather than interpolation used by previous authors is presented. Numerical examples validating the method are given. >
59 citations
TL;DR: In this article, a single balanced diode mixer is used to phase-lock neighboring oscillators in an active array, so that the phase difference between oscillators determines the direction of the main radiating beam.
Abstract: A new electronic beamsteering technique for active arrays is presented along with experimental results at 10 GHz. The technique uses a single balanced diode mixer to phase-lock neighboring oscillators in an active array. Each oscillator has its own antenna that radiates energy into free space, so the phase difference between oscillators determines the direction of the main radiating beam. An offset voltage added to the phase-locked loop controls the phase difference and beam direction. Experimental results demonstrate over 100/spl deg/ of adjustable phase difference between neighboring oscillators. Because of its simplicity, this technique has significant advantages over traditional beamsteering arrays. >
58 citations
TL;DR: In this article, a traveling-wave resonant funnel diode (TWRTD) pulse generator comprising transmission lines periodically loaded by GaAs/AlAs resonant tunnel diodes (RTD's) is fabricated.
Abstract: Traveling-wave resonant funnel diode (TWRTD) pulse generators comprising transmission lines periodically loaded by GaAs/AlAs resonant tunnel diodes (RTD's) are fabricated. The TWRTD pulse generators have convolved transition times of 3.5 ps when measured with an active probe. Using identical RTD's, TWRTD pulse generators can attain smaller transition times than those obtained with switching circuits employing a single RTD. >
54 citations
TL;DR: In this article, a versatile meander-line polarizer for arbitrary rotation of linear polarization is described and demonstrated, and it is shown that any polarization rotation can be accomplished by a simple mechanical rotation of this low-mass polarizer instead of rotating or modifying the much heavier antenna.
Abstract: A versatile meander-line polarizer is described and demonstrated for arbitrary rotation of linear polarization. This polarizer consists of eight-layer meander-line grids with rigid foam spacers between any two layers. It is shown that the field polarization rotation angle through this meander-line polarizer is twice the angle between the incident polarization and the polarizer grating lines. Hence, any polarization rotation can be accomplished by a simple mechanical rotation of this low-mass polarizer instead of rotating or modifying the much heavier antenna and its complex feed components. >
TL;DR: In this article, a six-element beam-scanning coupled MESFET oscillator array was designed and constructed, and resistively loaded transmission line networks were used to strongly couple each oscillator to its two nearest neighbors.
Abstract: A six-element beam-scanning coupled MESFET oscillator array was designed and constructed. Resistively loaded transmission line networks were used to strongly couple each oscillator to its two nearest neighbors. Measured H-plane radiation patterns indicate continuous scanning from /spl minus/30 to +40 degrees (from broadside). >
TL;DR: In this paper, a coplanar slow-wave structure that has the form of an interdigitated-meander line is proposed for use in MMIC's. But it is difficult to verify the correctness of the proposed structure.
Abstract: A novel coplanar slow-wave structure that has the form of an interdigitated-meander line is proposed in this letter for use in MMIC's. A simple analysis of this structure has been carried out by using empirical equations available in the literature and with the aid of CAD packages. A propagation velocity of about 2.8/sup /spl times//10/sup 7/ m/s was measured. Comparisons between theoretical and experimental results show good agreements. >
TL;DR: In this article, a rigorous full-wave analysis of 90/spl deg/E-plane mitered bends is obtained in a simple and accurate way by using the segmentation technique.
Abstract: A rigorous full-wave analysis of 90/spl deg/ E-plane mitered bends is obtained in a simple and accurate way by using the segmentation technique. The bend is divided into various regions of rectangular and triangular shapes, characterized by the generalised admittance matrix representation. The method is used to investigate the properties of 90/spl deg/ E-plane bends in rectangular waveguide. It is shown that it is possible to design the mitering so as to locate the matching frequency as desired within the operational frequency band. Design charts are given providing the optimal mitering as well as the relative bandwidth of the reflection coefficient. >
TL;DR: In this article, a finite-difference time-domain method with Floquet boundary conditions has been used to calculate the radiation characteristics of one-and two-dimensional phased array antennas for different scan angles in E- and H-planes.
Abstract: The finite-difference time-domain method with Floquet boundary conditions has been used to calculate the radiation characteristics of one- and two-dimensional phased array antennas for different scan angles in E- and H-planes. Considerable savings in computer memory and computation time are realized since only the central 3 elements for a l-D array and 3/spl times/3 elements for a 2-D array are to be modeled. >
TL;DR: In this article, the forward-backward autoregressive model is employed to extrapolate time domain signatures generated by the finite difference time domain algorithm with a view to speeding up the process of obtaining the frequency responses of EM systems.
Abstract: In this paper, the forward-backward autoregressive model is employed to extrapolate time domain signatures generated by the finite difference time domain algorithm with a view to speeding up the process of obtaining the frequency responses of EM systems. It is shown that the present method requires considerably lower-order predictors than those needed in other AR models, e.g, those based on Yule-Walker equations, and is therefore computationally efficient. >
TL;DR: In this article, the propagation effects of a modulated lightwave signal in an unbalanced Mach-Zehnder interferometer (UMZI) were studied and the experimental results of the microwave frequency response of the structure were obtained using two lightwave network analyzers HP8702A and HP8510B with an optoelectronic HP83420A.
Abstract: In this work, we study the propagation effects of a modulated lightwave signal in an unbalanced Mach-Zehnder interferometer (UMZI). Experimental results of the microwave frequency response of the structure are obtained using two lightwave network analyzers HP8702A and HP8510B with an optoelectronic HP83420A. It is shown that such an optical device could be used to perform a number of interesting microwave applications. The problems appearing in the coherent working regime and the possibility of integrated device realizations for millimeter-frequency signal processing are also discussed. >
TL;DR: In this article, a nonlinear model including the conduction, breakdown, and excessive current phenomenon is proposed for the nonlinear simulation of high-power circuits, which presents an improvement in terms of load line prediction and limits for the high power nonlinear circuit design.
Abstract: The nonlinear FET I(V) behavior, including gate conduction and breakdown, has been investigated using a pulse measurement setup. An excessive current source has been observed in addition to the usual gate breakdown current. From these measurements, a nonlinear model including the conduction, breakdown, and excessive current phenomenon is proposed for the nonlinear simulation of high-power circuits. This I(V) model presents an improvement in terms of load line prediction and limits for the high-power nonlinear circuit design. >
TL;DR: In this article, the complex propagation constant /spl gamma/ of any arbitrary length and characteristic impedance transmission line, embedded in an arbitrary environment, is derived based upon time domain analysis of short pulse propagation.
Abstract: This paper deals with the characterization of lossy transmission lines. The method developed here delivers the complex propagation constant /spl gamma/ of any arbitrary length and characteristic impedance transmission line, embedded in an arbitrary environment. This approach is based upon time domain analysis of short pulse propagation. Measurements are done with a commercial digital sampling oscilloscope. Only two transmission lines of different lengths are required in order to extract /spl gamma/ and to correct systematic errors of the measurement system. The problem of random errors is also addressed. The method is demonstrated with microstrip lines. A comparison of the developed technique with an other existing time domain approach and a classical frequency domain extraction is also carried out. >
TL;DR: In this article, a novel distributed analog multiplier is proposed, which employs Gilbert cells as the unit section of the distributed structure, and is built using 0.1/spl mu/m-gate-length InP HEMT's and uniplanar technology.
Abstract: A novel distributed analog multiplier is proposed. It employs Gilbert cells as the unit section of the distributed structure. The single-ended analog multiplier MMIC's are built using 0.1-/spl mu/m-gate-length InP HEMT's and uniplanar technology. The conversion gain is about -5 dB with LO power of 10 dBm, RF and IF 3-dB bandwidths are 38 and 16 GHz, respectively. >
TL;DR: In this article, a monolithic structure is presented for the tuning of MMIC's, either process deviations can be compensated or circuit parameters can be altered to meet different requirements, and measured results of a realized tuner agree well with the simulated model.
Abstract: A monolithic structure is presented for the tuning of MMIC's. With this tuner, either process deviations can be compensated or circuit parameters can be altered to meet different requirements. Measured results of a realized tuner agree well with the simulated model. Key design parameters are listed and a theoretical application for a narrow band amplifier at 27 GHz is simulated. >
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TL;DR: A 46.3 GHz dielectric resonator stabilized oscillator (DRO) using AlGaAs/GaAs heterojunction bipolar transistor (HBT) and monolithic microwave integrated circuit (MMIC) technology has been designed, fabricated, and characterized as discussed by the authors.
Abstract: A 46.3 GHz dielectric resonator stabilized oscillator (DRO) using AlGaAs/GaAs heterojunction bipolar transistor (HBT) and monolithic microwave integrated circuit (MMIC) technology has been designed, fabricated, and characterized. The oscillator exhibits 2.6 dBm output power with 5.8% dc-to-RF efficiency and less than /spl minus/132 dBc/Hz phase noise at 5 MHz offset from the carrier. To our knowledge, this is the highest frequency oscillator ever reported using HBT devices and MMIC technology. >
TL;DR: In this article, the design and construction of a relatively wideband quasi-optical voltage-controlled oscillator (VCO) is described, which uses a varactor-tuned microstrip patch antenna and may be used as an element in a power combining oscillator arrays.
Abstract: The design and construction of a relatively wideband quasi-optical voltage-controlled oscillator (VCO) is described. This VCO uses a varactor-tuned microstrip patch antenna and may be used as an element in quasi-optical power combining oscillator arrays. Measurements of this VCO indicate that over 1.3 GHz of tuning was achieved, with less than /spl plusmn/1.5 dB of amplitude variation over that range. >
TL;DR: In this paper, an active antenna array with optical input and beam scanning capability was developed, where the phase shift between antenna elements was controlled by means of unilateral injection locking, and the reference signal for injection locking was launched into an optical fiber by a multiquantum-well InGaAs-InGaAsP distributed feedback laser.
Abstract: An active antenna array with optical input and beam scanning capability was developed. The phase shift between antenna elements is controlled by means of unilateral injection locking. The reference signal for injection locking is launched into an optical fiber by a multiquantum-well InGaAs-InGaAsP distributed feedback laser. The RF signal is recovered by a photodetector at the other end of the link and fed to the RF circuit. Experimental results are presented and discussed. >
TL;DR: In this paper, four algorithms for time-frequency distributions are considered for the processing and interpretation of dispersive time-domain (TD) data: the short-time Fourier transform, frequency and time domain wavelets, and a new ARMA-based representation.
Abstract: Four algorithms for time-frequency (TF) distributions are considered for the processing and interpretation of dispersive time-domain (TD) data: the short-time Fourier transform, frequency and time-domain wavelets, and a new ARMA-based representation. The TF resolutions of the various distributions are discussed and compared with reference to results for the scattered fields from a chirped finite grating excited by a pulsed plane wave. The processing in the TF phase space extracts TD phenomenology, in particular the instantaneous dispersion relation /spl minus/ with its associated time-dependent frequencies-descriptive of the local TD Floquet modes on the chirped truncated grating. >
TL;DR: A simple and very efficient harmonic-balance technique is presented that is suitable for the steady-state analysis of nonlinear microwave and millimeter-wave circuits that require physics-based, fully numerical simulations of charge carrier transport in the solid-state device.
Abstract: A simple and very efficient harmonic-balance technique is presented that is suitable for the steady-state analysis of nonlinear microwave and millimeter-wave circuits that require physics-based, fully numerical simulations of charge carrier transport in the solid-state device. The practical integration of a numerical device simulator with a nonlinear circuit simulator requires a robust and fast circuit solution algorithm. The new circuit solution algorithm was applied to a test simulation of a 100- to 300-GHz multiplier circuit, achieving a savings in computational effort of 98% and a reduction in execution time by a factor of 33 over contending harmonic-balance techniques. >
TL;DR: In this paper, a bias-tunable active inductance-controlled HBT voltage-controlled oscillator (VCO) was demonstrated at both 4 and 10 GHz with the same output power and phase noise at 100 kHz offset from the carrier.
Abstract: This paper reports on the results of a novel HBT Voltage Controlled Oscillator (VCO) that incorporates a bias-tunable-active inductor. This development benchmarks the first demonstration of a tunable active inductance controlled HBT VCO of this type. The active inductor topology can obtain inductances of up to 10 nH at frequencies up to 10 GHz and can be bias-tuned over a similar range. VCO's were designed at 4 and 10 GHz by implementing different active inductance values. A 29% frequency tuning range from 3.54 to 4.73 GHz was obtained for the 4-GHz design. The output power varied from -1.2 to -0.2 dBm, respectively-less than 1 dB variation over the tuning range. The phase noise is -70 dBc/Hz at 100 kHz offset from the carrier. The new VCO topology can be implemented without the use of backside vias or microstrip-matching components and can be realized in a compact 1.0/spl times/0.7 mm/sup 2/ area. The variable active inductance VCO topology provides a compact, high performance alternative to the analog multi-vibrator oscillator circuit that generally has a smaller tuning capability and worse phase noise performance at microwave frequencies. >
TL;DR: In this article, a new time-domain hybrid symmetrical condensed TLM node was proposed to accommodate a graded mesh and model lossy anisotropic media described by diagonal tensors.
Abstract: This letter reports the development of a new time-domain hybrid symmetrical condensed TLM node. The new node can accommodate a graded mesh and model lossy anisotropic media described by diagonal tensors. The generalisation of an existing hybrid node to accommodate anisotropic media is also presented. The two hybrid nodes are complementary and provide the same computational advantages over the symmetrical condensed node originally proposed by Johns (1987). >
TL;DR: In this paper, a method for data extraction involving the direct use of Floquet's theorem is demonstrated along with a technique for exciting the mesh, which helps to reduce the total computation time.
Abstract: A number of methods are presented that improve the efficiency of Finite-Difference Time-Domain analyses of infinitely periodic structures. A procedure that provides a more effective implementation of absorbing boundary conditions, which enables the mesh to be drastically reduced in size, is presented. A method for data extraction involving the direct use of Floquet's theorem is demonstrated along with a technique for exciting the mesh, which helps to reduce the total computation time. These techniques are described and results are given that clearly show the improved performance of the absorbing boundaries. >
TL;DR: In this paper, the authors report the design, measured and simulated performance of a novel W-band monolithic, singly balanced resistive FET mixer utilizing 0.1/spl mu/m pseudomorphic AlGaAs/InGaAs on GaAs HEMT technology.
Abstract: We report the design, measured and simulated performance of a novel W-band monolithic, singly balanced resistive FET mixer utilizing 0.1-/spl mu/m pseudomorphic AlGaAs/InGaAs on GaAs HEMT technology. At an LO drive of +8 dBm, this mixer has exhibited a minimum measured conversion loss of 12.8 dB, nearly a 10 dB improvement over previously reported data in this frequency range. Furthermore, the mixer figure of merit, defined as P/sub 1-dB,in/-P/sub LO/, is at least +2 dBm, which is nominally 6 dBm better than that of comparable diode mixers at W-band. These results indicate the excellent potential of this mixer for integration with other circuit components in fully monolithic subsystems. >