Characteristics Of Transmission Lines Research Articles

S-parameter-measurement-based high-speed signal transient characterization of VLSI interconnects on SiO/sub 2/-Si substrate

A new S-parameter-based signal transient characterization method for very large scale integrated (VLSI) interconnects is presented. The technique can provide very accurate signal integrity verification of an integrated circuit (IC) interconnect line since its S-parameters are composed of all the frequency-variant transmission line characteristics over a broad frequency band. In order to demonstrate the technique, test patterns are designed and fabricated by using a 0.35 /spl mu/m complementary metal-oxide-semiconductor (CMOS) process. The time-domain signal transient characteristics for the test patterns are then examined by using the S-parameters over a 50 MHz to 20 GHz frequency range. The signal delay and the waveform distortion presented in the interconnect lines based on the proposed method are compared with the existing interconnect models. Using the experimental characterizations of the test patterns, it is shown that the silicon substrate effect and frequency-variant transmission line characteristics of IC interconnects can be very crucial.

Effect of finite-width curved substrate on a microstrip transmission line

The characteristics of a microstrip transmission line with a finite-width curved substrate are investigated in this letter by first employing the fast and accurate finite-element boundary-integral method to simulate the current distribution, then using a superresolution estimation of signal parameters via the rotational invariance technique (ESPRIT) algorithm to extract the characteristic parameters of the transmission line. The validity of our simulation tool is confirmed by a comparison of our numerical results and previously published results. Radiation losses due to the finite width of the substrate are also included in this letter. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 22: 322–323, 1999.

Short-pulse transient and characteristics of lossy binomial transmission lines with arbitrary linear and nonlinear termination

Lossy binomial transmission lines with arbitrary linear and nonlinear loads are modeled for use as short-pulse transformers in electrical and optical high-speed interconnects. An efficient method is proposed in this paper to characterize these lines as an equivalent circuit that consist of a cascaded connection of lumped networks and lossy uniform transmission lines in the frequency domain, while nonlinear problems are formulated and solved with time-domain scattering equations via a convolution technique. Results indicate that binomial lines present an advantage over exponential lines or uniform lines for the nonlinear loading effect, and they can be effectively used as a short-pulse transformer in such systems and devices as laser diodes, junction transistors, and metal-oxide-semiconductor field-effect transistors to enhance power coupling efficiency and reshape digital signal waveforms.

Analysis of cylindrical transmission lines with the finite-difference time-domain method

In this paper, the finite-difference time-domain (FDTD) method is used to calculate the propagation characteristics of cylindrical transmission lines. An efficient two-dimensional FDTD algorithm is developed by projecting the three-dimensional FDTD cell in the cylindrical coordinates onto the r-/spl phi/ plane. An effective absorbing boundary condition is employed to truncate the mesh at its outer radial boundary. Numerical results are derived for different cylindrical transmission lines and compared to data available in the literature. Specifically, the newly proposed cylindrical coplanar waveguide is studied both theoretically and experimentally.

Optimal dynamic load shedding policy for generation load imbalances including characteristics of loads

Modern electrical power systems are highly interconnected and heavily loaded. An emergency may occur as a result of a sudden increase in system load or unexpected partial or total outage of a generator. This paper presents an optimal dynamic load shedding policy for generation load imbalances. The effects of voltage and frequency characteristics of system loads, transmission lines, transformers and reactive power compensator are reported. Equality and inequality system constraints are also considered in the formulation of this nonlinear programming problem. The further effects of system average time constant, speed drop factor, load reduction ratio (load frequency sensitivity factor), system inertia, load shedding and spinning reserve are included. Furthermore a simple load distribution factor is considered in this algorithm. Results of the unified power system of lower Egypt have been presented to validate the algorithm and show its effectiveness. Copyright © 1999 John Wiley & Sons, Ltd.

Effect of depletion layer on the propagation characteristics of MIS transmission lines

The effect of the depletion region that forms in a metal-insulator-semiconductor (MIS) transmission line is considered. MIS lines are normally modeled without regard to this effect. Studies conducted here show that ignoring the depletion region leads to erroneous results in estimating the propagation characteristics. For example, ignoring the effect of the depletion region leads to errors in computing the propagation constant. For the quasi-TEM mode of operation, the imaginary part of the propagation constant (attenuation constant) is off by up to 15%, and the phase constant is off by up to 3%. Moreover, for the slow-wave mode of operation, ignoring the depletion region leads to totally erroneous results, with errors of 50%-90%. Results presented here were obtained using a spatial-domain analysis utilizing the Green's function for a generalized multilayered lossy substrate.

Miniaturized millimeter-wave masterslice 3-D MMIC amplifier and mixer

Masterslice three-dimensional MMIC (3-D MMIC) technology has (even in the millimeter-wave region) the advantages of high integration levels, simple design procedures, short turnaround time, and low fabrication cost. This paper clarifies the advantages of the thin-film microstrip line by drawing comparisons to the characteristics of other transmission lines. The simple design procedures of the masterslice 3-D MMIC are elucidated by referring to fabricated MMICs. A V-band amplifier and an image rejection mixer fabricated by using the same master array are demonstrated. The V-band amplifier offers an 8-dB gain and a 5.3-dB noise figure in the area of just 0.27 mm/sup 2/. The image rejection mixer achieves a conversion gain of /spl sim/10 db and an image rejection ratio of 20 db. The performance of the millimeter-wave 3-D MMIC's is competitive with those of the conventional planar-formed MMIC's.

Performance of Cu‐ and Ag‐based microstrips up to millimetre wave frequencies

Attenuation characteristics of microstrip transmission lines on alumina substrates up to 50GHz are discussed. The lines under test came from three different manufacturers, each of whom used different processes to realise the transmission lines. Two of the manufacturers used silver (Ag) paste, whereas the process of one of the manufacturers was copper (Cu) based. Each manufacturer used identical alumina substrates and identical test pattern files so that the measured attenuation properties reflected manufacturer’s capability to fabricate microstrips and the quality of the metal system used. Measurements showed that the attenuation of copper microstrips was slightly lower than that of the silver microstrips, but the difference was small. Measured attenuation (S21) of about 50Ω microstrips was approximately 0.5db/cm at 30GHz and 0.8dB/cm at 50GHz, respectively. The loss coefficient, αt, of about 0.035dB/mm at 40GHz was obtained for the Cu microstrips. Such an attenuation is reasonable for many practical applications in the microwave and millimetre wave regions.

Characteristics of microstrip transmission line on grooved dielectric substrate

ABSTRACT: This letter proposed a new type of microstrip transmissionline called the ‘‘groo ¤ ed microstrip line GML ’’ for low conductor and()dielectric losses. The proposed structure is realized by using a dielectricsubstrate containing ¤ ertical groo ¤ es. The corrugation in the dielectricsubstrate helps in reducing the concentration of the current on the strip,which in turn reduces the conductor losses in the transmission medium.In addition, partial remo ¤ al of the material from the dielectric substratereduces the dielectric loss as well. The method of lines MOL is used to()calculate the effecti ¤ e dielectric constant and the associated conductorand dielectric losses. Finally, a comparison of the computed results of thegroo ¤ ed microstrip line is made with those of a con ¤ entional microstripline. Q 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 17:55]57, 1998. Key words: microstrip line; method of lines; conductor and dielectriclosses; groo ¤ ed substrate 1. INTRODUCTION

Characterization of balanced transmission line by microwave techniques

This paper presents a method of experimentally characterizing a balanced transmission line using microwave techniques. An unbalanced measurement instrument and the transmission line under test must he connected by a balun, and the effect of the balun must be removed from the measured data. Deembedding techniques are discussed briefly, and several baluns are evaluated. Two methods of performing the measurement are presented. The first uses a one-port measurement where known loads are measured from the end of various lengths of transmission line. The second uses two-port measurements with different transmission-line lengths, and is more effective for measurement of line loss. Experimental results are presented for 2 mm toughened plastic sheath (TPS) twin and earth power cable for the range of 0.3-300 MHz.

A flip-chip MMIC design with coplanar waveguide transmission line in the W-band

This paper describes a design method for flip-chip monolithic millimeter-wave integrated circuits (MMICs) with a coplanar waveguide (CPW) transmission line for W-band applications. We proposed a test structure for obtaining accurate flip-chip CPW line models. We examined the transmission line characteristics of the CPW line using the test structure in the millimeter-wave range and modeled them. Using the CPW line models, we designed and fabricated both two- and three-stage amplifiers using 0.15-/spl mu/m InGaP/InGaAs high electron-mobility transistor technology. The maximum power gain of the two-stage amplifier is 12 dB at 79 GHz. The three-stage amplifier has a maximum power gain of 16 dB at 77 GHz. The agreement of measured S-parameters with calculated results demonstrates that the proposed test structure is suitable for characterizing flip-chip CPW lines and provides very accurate models.

An alternative way to analyse non-reciprocal and non-symmetric transmission lines

There is interest in the characteristics of non-reciprocal and non-symmetric transmission lines (NNTL) in microwave and millimetre-wave integrated circuits. An alternative way to analyse these lines is provided where the theory of conventional transmission lines (CTLs) can be adapted if different distributed line parameters for waves propagating in opposite directions are used. Closedform expressions related to the characteristic impedances, complex propagation constants, and modified distributed parameters are given for a lossy NNTL.

Characteristics of coplanar transmission lines on multilayer substrates: modeling and experiments

Characteristics of coplanar transmission lines on multilayer substrates expressed in analytic formulas have been obtained using conformal mapping. The accuracy of these formulas has been verified experimentally on a variety of coplanar transmission lines using differential electro-optic (DEOS) sampling. For coplanar waveguides, the theory differs from the experiment by less than 3%; for coplanar striplines, the differences are less than 6%.

Microwave characterization of coplanar waveguide transmission lines fabricated by ion implantation patterning of YBa/sub 2/Cu/sub 3/O/sub 7-δ/

We report on the application of Si and Al ion-implantation patterning to the fabrication of low-loss microwave transmission lines in high-temperature superconductor (HTS) thin films. Using this technique, we have fabricated coplanar waveguide (CPW) transmission lines in YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// (YBCO) thin films deposited on LaAlO/sub 3/ substrates. We have used both resonant and broadband measurements in order to characterize the performance of the resulting transmission line structures. For the broadband measurements, on-wafer calibrations were used to obtain accurate S-parameters and transmission line propagation constants up to 25 GHz. The propagation constants of the ion-implanted transmission lines do not differ significantly from those of lines patterned using conventional ion milling over the frequency range studied, with a value for the attenuation constant of approximately 0.03-0.04 dB/cm at 50 K and 10 GHz. The relatively low losses of the ion-implanted devices demonstrate the effectiveness of this method of patterning for HTS microwave device fabrication.

Multiconductor transmission line characterization

This paper presents a measurement method that completely characterizes lossy printed multiconductor transmission lines. It determines not only the matrices of impedances and admittances per unit length describing the transmission line in the conductor representation, but also the propagation constants, characteristic impedances, and cross-powers for each mode supported in the line. We apply the method to a pair of lossy coupled asymmetric microstrip lines.

Millimeter-wave wide-band amplifiers using multilayer MMIC technology

This paper describes millimeter-wave wide-band single-ended and balanced amplifiers using novel multilayer monolithic microwave/millimeter-wave integrated circuit (MMIC) technology. The fundamental characteristics of thin-film transmission lines and a 50-GHz-band multilayer MMIC directional coupler are described through measurements up to 60 GHz. A single-ended amplifier fabricated in a 1.1 mm/spl times/0.8 mm area, shows a gain of about 12 dB with a noise figure of better than 5 dB around 50 GHz. A balanced amplifier fabricated using the multilayer MMIC directional couplers and single-ended amplifiers, shows a gain of 10-17 dB with input and output return losses of better than 14 dB from 33 to 53 GHz. The transmission lines and directional couplers can be effectively combined with millimeter-wave active circuits without degrading the circuit performance or increasing the circuit area. To our knowledge, these are the first millimeter-wave active circuits employing multilayer MMIC technology.

Dispersion characteristics of microstrip transmission line on glass microwave IC's

Measurement of the effective dielectric constant of microstrip transmission line on glass for the frequency range of 5-35 GHz are presented. These measurements indicate that there is very little dispersion in 200-/spl mu/m-thick glass for frequencies up to 35 GHz. Further, electromagnetic analysis shows that the dielectric constant of glass changes from 4.05 to 4.00 when the frequency varies from 5 to 35 GHz, somewhat compensating for the dispersion.

FDTD analysis of submillimeter-wave CPW with finite-width ground metallization

The dispersion and attenuation characteristics of conductor-backed coplanar transmission lines with finite-width ground metallizations are studied in the frequency range up to 1 THz. The finite-difference time-domain (FDTD) method is used for analysis. Open boundaries are described by means of Berenger's perfectly matched layer. The results are compared to electrooptic measurements. They show that introducing ground metallizations of finite width causes distinct changes in attenuation and dispersion characteristics.

Parameter extraction and correction for transmission lines and discontinuities using the finite-difference time-domain method

The finite-difference time-domain (FDTD) method is useful for performing broadband characterization of uniform transmission lines and discontinuities. Modeling a geometry often requires the implementation of an absorbing boundary condition (ABC). When this is the case, numerical reflections from the ABC's will add significant error to the calculated transmission line or scattering (S) parameters. This paper introduces a simple post-processing algorithm for extracting these parameters and correcting for numerical reflection error. Furthermore, this method is shown to have a unique relationship to Prony's method. Practical application and limitations of this technique are also discussed. Finally, the impedance and propagation constant of a microstrip line are calculated using this method.

Electrical performance of interconnects in polyimide-copper thin-film multilayers on ceramic substrate

Thin-film multilayer substrate technology with dielectric layers made of polyimide resin requires openings on the ground plane for the outgassing of the resin. This paper describes a full electrical characterization of transmission lines in a multichip module based on thin-film multilayer on ceramic. Both time and frequency domain methods were used for the experimental characterization. Measured and modeled performances are compared for three kinds of ground opening geometries.