Propagation characteristics of MIS transmission lines withinhomogeneous doping profile

The authors present a hybrid-mode analysis of slow-wave MIS (metal-insulator-semiconductor) transmission lines with a gradually inhomogeneous doping profile. In general it was found that, in comparison with homogeneously doped semiconductor layers, a Gaussian-type doping distribution results in lower losses for the slow-wave mode in both thin- and thick-film MIS CPWs. While the effect of the doping profile is more pronounced in thin-film structures which support a slow-wave mode only up to 3 GHz, it is less significant in thick-film structures. On the other hand, numerical analysis indicates that thick-film structures can support a slow-wave mode at moderate loss up to 40 GHz. The behavior of MIS microstrip lines is similar to that of MIS CPWs, except that for thick-film transmission lines an increase in losses can be observed when the doping profile becomes inhomogeneous. The numerical investigation was carried out using the method of lines. Several transmission lines have been investigated, and results are presented for microstrip, coupled microstrips, and coplanar lines     

New prospective coplanar metal-insulator-semiconductor (MIS)monolithic structure

Research work on various MIS transmission lines is well documented. Useful slow-wave propagation with low loss is always exhibited in recently proposed lower frequency ranges (several GHz). The author is concerned with the essential properties of the micrometre-size coplanar MIS lines. A new loss-reducing monolithic MIS is proposed with reference to physical considerations to ensure a low-cost mechanism     

Hybrid-mode analysis of homogeneously and inhomogeneously dopedlow-loss slow-wave coplanar transmission lines

A hybrid-mode analysis is presented to characterize the propagation properties of uniplanar slow-wave MIS (metal-insulator-semiconductor) coplanar transmission lines. The effect of homogeneous versus gradually inhomogeneous doping profile is investigated as well as the influence of the metal conductor losses and finite metallization thickness on the slow-wave factor and the overall losses. Numerical results indicate that thick-film MIS CPWs can support a slow-wave mode with moderate loss up to 40 GHz when the line dimensions are kept in the micrometer range. Furthermore, it is found that an inhomogeneous doping profile can reduce the overall losses and that the effect of metal conductor losses in heavily doped MIS structures is only marginal. On the other hand, in weakly doped or insulating GaAs material a lossy metal conductor leads to a higher propagation constant, exhibiting a negative slope with increasing frequency     

Slow-Wave Coplanar Waveguide on Periodically Doped Semiconductor Substrate

A metal-insulator-semiconductor (MIS) coplanar waveguide with periodically doped substrate is described. An efficient numerical method is introduced in order to obtain the propagation constants and the characteristic impedances of the constituent sections of each period. Using the results, the characteristic of the periodic MIS coplanar waveguide is analyzed by Floquet's theorem. The theoretical study shows reduction of attenuation and enhancement of the slow-wave factor at certain frequencies, compared to the uniform MIS coplanar waveguide. This structure is experimentally simulated and shows good agreement theory.     

Low-loss slow-wave propagation along a microstructure transmission line on a silicon surface

We report observations of relatively low-loss propagation in the frequency range of 1.0 to 12.4 GHz using a micrometer-size coplanar MIS transmission line fabricated on a heavily doped N + silicon surface. This low-loss mode of propagation is found to be accompanied by significant wavelength reduction which suggests that such lines may be useful as transmission media for distributed components in silicon monolithic microwave integrated circuits (MMICs).     

Quasi-TEM Analysis of "Slow-Wave" Mode Propagation on Coplanar Microstructure MIS Transmission Lines

We present a simple quasi-TEM analysis of "slow-wave" mode propagation on micron-size coplanar MIS transmission lines on heavily doped semiconductors and compare theoretical results with measurements on four such structures at frequencies from 1.0 to 12.4 GHz. Excellent agreement is found, which shows that the "slow-wave" mode propagating on these transmission lines is, in fact, a quasi-TEM mode. Relatively low-loss propagation along with significant wavelength reduction is observed. Conduction losses of the metal, which have been tacitly ignored in previously published "full-wave" treatments of "slow-wave" mode propagation, are included in the theory and are shown to dominate the attenuation at frequencies below 25 GHz and to still be significant at frequencies up to at least 100 GHz.     

Characterization of MIS structure coplanar transmission lines forinvestigation of signal propagation in integrated circuits

A full-wave analysis of metal-insulator-semiconductor (MIS) structure micron coplanar transmission lines on doped semiconductor substrates is carried out using a finite-difference time-domain approach. Metal conductor loss is taken into account in the analysis. Line parameters and electromagnetic field distributions are calculated over a wide frequency range involving slow-wave and dielectric quasi-transverse-electromagnetic mode limits. Measurements of these line parameters, varying substrate resistivity from 1 to 1000 Ω-cm, in the frequency range up to 40 GHz are also presented, and these agree with the analysis quite well. On the basis of these results, an equivalent circuit line model is induced and some considerations on the relationship between line structure and properties made     

Analysis of Slow-Wave Coplanar Waveguide for Monolithic Integrated Circuits

The slow-wave characteristics of an MLS coplanar waveguide are analyzed using two different full-wave methods mode-matching and spectral-domain technique. The theoretical results obtained with them and the experimental values are in good agreement. Several important features of the MIS coplanar waveguide are presented along with some design criteria.     

CAD models for asymmetrical, elliptical, cylindrical, andelliptical cone coplanar strip lines

By the conformal mapping method, we give analytical closed form expressions for the quasi-TEM parameters for asymmetrical coplanar strip lines (ACPSs) with finite boundary substrate. Then, based on the analysis of ACPSs, elliptical coplanar strip lines (ECPSs) and cylindrical coplanar strip lines (CCPSs), and elliptical cone coplanar strip lines (ECCPSs) are studied. Computer-aided-design oriented analytical closed-form expressions for the quasi-TEM parameters for ACPSs, ECPSs, CCPSs, and ECCPSs are obtained. All of the expressions are simple and accurate for microwave circuit designs and are useful for transmission-line theory and antenna theory. The reasonableness of the method and results are verified and various design curves are given     

硅衬底上共面线的特性及应用

基于理论和实验结果对深亚微米硅集成电路中的共面传输线的特性进行了研究,提出了硅衬底上传输线分布参数的提取方法和减小共面线衰减的一些设计准则.成功地将共面线应用在深亚微米高速集成电路的设计中,并给出了放大器芯片和共面线的测试结果.测试结果表明:在深亚微米CMOS高速集成电路中,用共面线实现电感是一种行之有效的方法.     

Rigorous analysis of planar MIS transmission lines

The realisation of distributed microwave integrated circuits can be expected by using very low phase velocity propagation modes on MIS and Schottky planar transmission lines. Up to now, the frequency behaviour of such lines has been obtained by using analytical models. We present a rigorous analysis of a MIS microstrip line, the validity of which is testified by comparison to experimental values.     

Electromagnetic coupling of coplanar waveguides and microstriplines to highly lossy dielectric media

The spectral-domain technique is utilized to analyze the coupling characteristics of coplanar waveguides and microstrip lines coupled with multilayer lossy dielectric media. Numerical results illustrating the dispersion characteristics of coplanar and microstrip lines, as well as the various electric field components coupled to highly lossy dielectric media, are presented. It is shown that the presence of a superstrate of lossless dielectric between the coplanar waveguide and the lossy medium plays a key role in setting up an axial electric field component that facilitates leaky-wave-type coupling to the lossy medium. The thickness of the superstrate relative to the gap width in the coplanar waveguide is important in controlling the magnitude of this axial electric field component. The coupling characteristics of the microstrip and coplanar lines are compared, and results generally show improved coupling if coplanar waveguides are utilized. Values of the attenuation constant α are higher for coplanar waveguide than for microstrip line, and for both structures α decreases with frequency     

共面五条直线的联合射影不变量

在计算机视觉中，共面五条直线的射影不变量已有非常重要的应用。但是由于共面五条直线射影不变量的形式很多，而且这些不变量和直线的排列顺序有关，这给不同图像中的不变量的匹配带来很大的困难。     

Characteristics of coplanar transmission lines on multilayersubstrates: 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%     

Analytical analyses of v, elliptic, and circular-shaped microshieldtransmission lines

Several new types of monolithic coplanar transmission lines, v, elliptic, and circular-shaped microshield coplanar waveguide, have been proposed. The characteristic impedance expressions for those transmission lines have been derived using the conformal mapping method (CMM) under the assumption of the pure-TEM propagation and zero dispersion. In the analyses of the elliptic and the circular-shaped microshield coplanar lines, the methods using the graphical approximation and taking the geometric mean value of the upper and the lower bounds to the size of the line are put forward to calculate the characteristic impedance of this two kinds of microshield coplanar lines. The numerical results show the effects of the different shaped microshield walls on characteristic impedances     

Dispersion of Picosecond Pulses in Coplanar Transmission Lines

The dispersion of coplanar-type transmission lines has been extended to the terahertz regime to examine the distortion of picosecond electrical pulses. Dispersion of coplanar waveguides is compared to equivalent microstrip lines. Agreement with available experimental data is demonstrated for coplanar strips, An approximate dispersion formula for coplanar waveguides is also reported for CAD applications.     

Analysis and applications of modified coupled coplanar lines

Modified coupled coplanar lines, compatible with the classical and conductor-backed coplanar waveguides, are analysed using the quasistatic and full-wave spectral domain methods. Results of the analysis are utilised for designing a 10 dB directional coupler. Measured isolation of the coupler is higher than 33 dB in the bandwidth up to 5 GHz.     

Field distributions in supported coplanar lines using conformalmapping techniques

We use conformal mapping techniques to derive the analytical expressions for calculating the field distributions in supported coplanar lines. Our calculations agree well with the results obtained using the point matching method. Our method is an extension of the approximate technique proposed by Veyres and Hanna (1980), and provides an accurate and fast calculation of the field distributions. This method can be extended to the analysis of other coplanar lines widely used in monolithic microwave integrated circuits (MMIC) and optical integrated circuits (OIC) applications     

Dissipation Loss Effects in Isolated and Coupled Transmission Lines

This paper describes a computer-aided analysis of dissipation losses in uniform isolated or coupled transmission lines for microwave and millimeter-wave integrated-circuit applications. The analysis employs a quasi-TEM model for isolated transmission lines and for the even- and odd-mode transmission lines associated with coupled-line structures. The conductor and dielectric losses are then related to equivalent charge density distributions, which are evaluated using a method-of-moments solution. The transmission lines treated by this analysis may contain any number of Iossy conductors and inhomogeneous dielectrics, consisting of any number of different homogeneous dielectric regions. A development is provided to explicitly relate the four-port terminal-electrical performance of directional couplers to evaluated even- and odd- mode loss coefficients. Examples of evaluated losses are presented in graphical form for isolated lines of inverted microstrip and trapped inverted microstrip and edge-coupled microstrip with a dielectric overlay. The analysis accuracy has been confirmed using microstrip and coplanar waveguide configurations. A comparison is made of the total loss characteristics for microstrip, coplanar waveguide, inverted microstrip, and trapped inverted microstrip. Calculations are compared with measurements for the coupled-line structure. Accuracy of the solution and suggested refinements are discussed. Five computer programs are documented.     

E-plane scan performance of infinite arrays of dipolesprinted on protruding dielectric substrates: coplanar feed line andE-plane metallic wall effects

The effects of coplanar feed lines and of E-plane cavity walls on the performance of infinite arrays of dipoles printed on protruding dielectric substrates are investigated. In order to do so, two unit cell configurations are studied: (1) the dipole element fed by coplanar transmission lines and (2) the dipole element fed by coplanar transmission lines with finite-height metallic walls added parallel to the H-plane of the array. The element active impedances are calculated for these configurations, and they are compared with those obtained from arrays of dipoles without coplanar feed lines. Effects of the dielectric substrate permittivity and of its thickness on the array element active impedance are included. The results show that the arrays of dipoles with the coplanar feed lines exhibit feed-line-induced blindnesses which reduce considerably the scan volume of the array. It is also shown that these feed line effects are reduced for thicker or higher permittivity substrates, and that the insertion of electric walls is one possible avenue for eliminating these anomalies