On the Cutoff Wavelength of Rectangular-Shaped Microshield Line by Edge Element Method

In this paper, the cutoff characteristic of rectangular-shaped microshield transmission line has been analysed by edge element method. Dependence of cutoff wavelengths on the thickness of metallic signal strip, dielectric constant of dielectric substrate and the width of the rectangular-shaped ground conductor are presented in tabular form. Numerical results in this paper have important values in design of rectangular-shaped microshield lines in microwave and millimeter wave integrated circuits.     

Micromachined W-band filters

Results are presented for high performance planar W-band filters based on silicon micromachining techniques common in microsensor fabrication. Two types of micromachined planar transmission lines are studied: microshield line and shielded membrane microstrip (SMM) line. In both of these structures, the conducting lines are suspended on thin dielectric membranes. These transmission lines are essentially “floating” in air, possess negligible levels of dielectric loss, and do not suffer from the parasitic effects of radiation and dispersion. A 90 GHz low pass filter and several 95 GHz bandpass filters are tested and display excellent performance which cannot be achieved with traditional substrate supported circuits in CPW or microstrip configurations. A full-wave finite-difference time-domain (FDTD) technique verifies the measured performance of the W-band circuits and provides a basis for comparison between the performances of membrane supported circuits and equivalent substrate supported circuits     

梯形屏蔽共面波导及共面耦合线特性阻抗的计算

提出了适用于ＭＭＩＣ设计一类新型共面传输线，它包括梯形屏蔽共面波导（ＳＭＣＰＷ）梯形屏蔽共面耦合线（ＳＭＣＣＬ）共面耦全梯形屏蔽线（ＣＣＳＭＬ）推导出用于计算这些传输线的ＴＥＭ参数的解析公式，数值计算结果显示了此类共面传输线的性质。     

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     

变形矩形和V形微屏蔽线传输特性的矢量有限元计算

微屏蔽线在使用过程中难免会产生变形。本文利用矢量有限元法讨论了矩形微屏蔽线和V形微屏蔽线的变形对其传输特性的影响,其中传输特性包括主模截止波长、单模带宽和主模电场结构。计算结果显示,两种微屏蔽线的变形对三种传输特性均有较大影响,这些数值计算结果对两种微屏蔽线在使用过程中出现变形时对整体器件的影响有较强的指导意义。     

微屏蔽三线对称结构带通滤波器设计

对薄膜支撑空腔型微屏蔽传输线进行分析,提出微屏蔽传输线的物理结构。为了验证微屏蔽传输线在毫米波应用的优势,利用类比平行耦合微带线滤波器的方法设计了一种4阶切比雪夫三线对称结构微屏蔽线滤波器。通过对该微屏蔽腔体结构进行HFSS仿真,得到中心频率35 GHz的宽带滤波器,带宽15 GHz,带内插损小于0.5 dB,带外抑制>40 dB@53 GHz,器件尺寸8.24 mm×1.5 mm×0.65 mm。该设计为基于平面传输线的滤波器在毫米波频段的实现提供了一种可行的方法。     

Characterization of V-groove coupled microshield line

A new membrane supported air-filled V-groove coupled microshield has been investigated using finite element method. The even- and odd-mode characteristic impedances and the effective dielectric constants have been computed. The dependence on various dimensions has been studied. The crosstalk levels between adjacent lines have been compared with that in coupled microstrip lines, coupled microstrip lines with lateral ground planes, and V-groove structures with and without metallization in the groove.     

Analytical analysis of circular-shaped microshield and conductor-backed coplanar waveguide

In this paper, a new type of circular-shaped microshield and conductor-backed coplanar waveguide is proposed. Analytic closed-form expressions for characteristic impedance and effective dielectric constant for the new line are obtained using conformal mapping method under the assumption of pure-TEM propagation and zero dispersion. The new waveguide proposed by this paper can reduce radiation to much less than the conventional coplanar waveguide and microstrip, and can reduce the current concentration at both the edges of the strip conductor.     

Simple and explicit formulas for the design and analysis ofasymmetrical V-shaped microshield line

This paper presents some simple, explicit and practical formulas for the evaluation of the quasi-TEM characteristic parameters of asymmetrical V-shaped microshield line, based on a conformal mapping procedure. These formulas give very accurate results in terms of elementary functions rather than the exact solution in terms of difficult functions. Two sets of expressions are described using first and second order approximations. These equations are easy to implement, thus making it an excellent choice for use in computer aided design, analysis and optimization of V-shaped microshield structures     

Analysis and performance of superconductive coaxial transmission lines

This paper discusses the mechanisms affecting metallic conduction and dielectric properties in relation to a low temperature transmission line to provide a basis for analysis of the characteristic change, and the remaining losses at low temperature. Specific attention is given to lines employing Teflon or polyethylene as dielectrics, and operating up to 10 Gc. The construction and measured performance of a number of long superconductive coaxial lines is given in support of the analytical results.     

Millimeter-Wave Dielectric Image Line Detector-Circuit Employing Etched Slot Structure

In an earlier paper [1] slots in the ground plane are investigated as new circuit elements in dielectric image lines. In this paper slots in dielectric image lines employing metallized dielectric substrates as the ground plane are investigated. It is shown that this configuration can be used to realize truly integrated dielectric image line semiconductor circuits. As an example the design and performance of a detector circuit for 26 to 40 GHz is presented.     

CAD models of losses for symmetric elliptical and circular cylindrical coplanar strip lines

This article addresses a CAD-oriented closed-form expressions for dispersive and conductor thickness-based line parameters for symmetrical coplanar strip lines (CPS) on a finite-thickness dielectric substrate. The conductor and dielectric losses are also computed. The models are extended to non-planar CPS – elliptical coplanar strip line (ECPS) and cylindrical coplanar strip lines (CCPS). Finally, accurate circuit model for these structures is also presented. The results between 1 and 60?GHz are compared against the results of HFSS and Sonnet and also against the experimental results. The average deviation of the model against the experimental result is 2.06%.     

Effect of the Dielectric Anisotropy on the Propagation Properties of Microstrip Tapers with Height Variations

This paper deals with the design and application of nonuniform microstrip transmission lines on anisotropic substrates. A rigorous analysis is based on the use of Hertz vector potentials, moment method and transmission line theory to determine the dispersion characteristics of single and coupled tapered microstrip lines for accurate performance prediction. Results are presented for the main parameters providing the necessary information to design several devices on tapered microstrip, with variation on the strip width and dielectric height, for (M)MIC and antennas applications. A good agreement was observed with the results available in the literature for tapered lines on isotropic substrates.     

Planarization properties of hydrogen silsesquioxane (HSQ) influence on CMP

Low dielectric constant materials are now required as intermetallic dielectrics to reduce RC delay in advanced technologies. Hydrogen silsesquioxane (HSQ) is a spin-on dielectric with a dielectric constant around 3. Local planarization of HSQ and its impact on the global planarization due to CMP process was studied. Local planarization of HSQ and its impact on the global planarization due to CMP process was studied. When lines and spaces are equal, HSQ shows a good planarization for lines smaller than 20 μm. In this case, the HSQ thickness on metal line is equal to 2500 Å, which is the minimum which can be obtained for this metal thickness and HSQ deposited. For various environments of the metal line HSQ planarizes better for small lines in a dense zone created by an array of lines or plates of metal. For the CMP process the planarization is good for small lines, as for HSQ but in an array of lines only. Plates must be totally prohibited for CMP process. Finally, for an intermetal dielectric including HSQ the goal of CMP is no more a local planarization as for gap fill but a large scale intra-die planarization.     

一种新型LiNbO3光波导调制器的准静电分析

本文提出利用共面微屏蔽线实现新型结构的铌酸锂光调制器，并利用保角变换的方法计算该结构调制器的特性阻抗，等效折射率，调制宽，并根据此计算结果算出所需的调制电压。结果表明昨用该结构有效地减小了调制器的速度失配，增加了调制带宽，是一种可行性的方案。本文并根据计算结果填充了较理想的调制器的尺寸大小。     

CAD modeling of coplanar waveguide (CPW) air-bridges

In this paper, first, a comprehensive review of existing models for the coplanar waveguide (CPW) air-bridge is presented. Then, a new CAD model is proposed, in which the bridge is modeled as a small section of a microshield line, whose characteristics are obtained using the conformal mapping technique. Our results are in good agreement with full-wave results.     

Strip Line with Rectangular Outer Conductor and Three Dielectric Layers

A general method is proposed for analyzing the transmission line characteristics of strip lines with rectangular outer conductor and multidielectric layers within a TEM wave approximation. This method uses Green's function for formulating the problem and a variational principle for obtaining practical solutions. The case of the microstrip line is first discussed, and numerical results are found to be consistent with other theories and experiments. The case of strip lines with a rectangular outer conductor and three dielectric layers is examined for various combinations of dielectric materials. Other applications of Green's function and the theoretical limitation of this method are also described.     

Characteristic impedance of microshield lines with arbitrary shieldcross section

A generalized potential-matching method incorporating reflection matrices is developed to calculate the capacitance of microshield lines with trapezoidal, circular, and V-shaped shields. Both completely shielded and half-shielded lines are analyzed. The effects of membrane thickness, strip width, and gapwidth on the characteristic impedance are studied     

A low-impedance coplanar waveguide using an SrTiO3 thinfilm for GaAs power MMIC's

A novel structure for coplanar-waveguide transmission lines with low impedance and low loss is demonstrated in this paper. The new structure simply has a high dielectric SrTiO₃ thin film underneath the coplanar conductors. Due to the high dielectric constant of SrTiO₃, the coplanar line exhibited characteristic impedance as low as 18 Ω with a slot width of 5 μm and the center conductor width of 50 μm, while a conventional coplanar line on GaAs showed only 30 Ω with the same configuration. The newly developed coplanar structure is easily applicable for present GaAs monolithic-microwave integrated-circuit (MMIC) technology, especially for power MMIC's and low-impedance devices