Full-wave analysis of coplanar strips considering the finite stripmetallization thickness

An extensive analysis, based on a full-wave mode-matching technique, is described for coplanar strips (CPS) incorporating the strips' finite metallization thickness. Results for the effective dielectric constant and characteristic impedance are presented to show the effect of the metallization thickness. It is found that the characteristic impedance has a strong dependence on the metallization thickness, which signifies the fact that the finite metallization thickness needs to be considered in designing practical microwave circuits employing CPS. Numerical results of CPS with zero metallization thickness obtained using this method are found to be in good agreement with those published previously. Extensive investigation of the numerical convergence of these results is also described     

Capacitance computation for CPW discontinuities with finitemetallization thickness by hybrid finite-element method

A variational equation is derived for the capacitances of coplanar waveguide (CPW) structures with finite metallization thickness. The equation is expressed in terms of the static potential in the slot region and is solved by applying the hybrid finite-element method (FEM). In the case of small metallization thickness, it is reduced to a perturbation formula for the incremental capacitances. Numerical results for the equivalent capacitances of various discontinuities with finite metallization thickness are presented and compared with measured data. The reasonable agreement between the measured data and the theoretical results validates the present approach. Being simple and computationally efficient, the method is suitable for dealing with extensive CPW discontinuity problems where the metallization thickness is not negligible     

一种分析有限金属厚度和有限电导率的共面波导结构的有效方法

采用分区直线法与渐近拟合阻抗边界条件相结合的方法,对一种具有限金属厚度和有限电导率的共面波导结构的相对介电常数和损耗特性进行了分析,这是一种全波分析方法,并且可以适用于趋肤深度与金属厚度之比为任意数值的情况。计算实例证明了该方法的正确性和有效性。     

Analysis of a shielded microstrip line with finite metallizationthickness by the boundary element method

A boundary element method is presented for the quasi-static analysis of a shielded microstrip line with finite metallization thickness. The analysis is based on the solution of a system of boundary integral equations which are derived from Green's second identity. Numerical results for the charge distribution along the strip and the effects of metallization thickness on line characteristics are presented. The results show good agreement with data available in the literature     

金属栅厚度对介质波导漏波天线辐射特性的影响

本文研究了厚金属栅加载介质插入波导漏波天线的辐射特性,运用电磁场的网络解析法的推广模型建立起本征值方程。数值结果表明,金属栅厚度对漏波天线波求方向影响较小,但对漏波天线的辐射效率和波束宽度有明显的影响。     

The method of lines for the analysis of planar waveguides withfinite metallization thickness

The method of lines is extended to calculate waveguide structures with finite metallization thickness. The normally used range of metallization thickness is not a limit for the method. Particularly when calculating small or moderate thicknesses, it is possible to derive the dispersion constant with only one computed result. When using the optimal edge parameter, P_opt, for that computation, the deviation from the exact dispersion constant is less than 0.5%. The advantage of the method of lines is that only small line numbers are necessary. Hence, the computing time is very small     

Explicit formulas of propagation characteristics for unilateral finline

In this paper, the unilateral fintine characteristics including finite metallization thickness and depth of mounting grooves are analysed by transverse resonance principle combining moment method. The numerical results are presented, the influence of the finite metallization thickness and depth of grooves on the propagation characteristics are investigated in detail. Finally, a set of explicit formulas for the propagation characteristics of unilateral fintine are developed. To be compared with the rigorous numerical results, the errors are within ±1% for phase constant and ±2% for characteristic impedance respectivelly.     

Analysis of the Characteristics of an Earthed Fin Line

This paper presents a theoretical and experimental investigation of the effective permittivity and the characteristic impedance of the earthed unilateral fin line. Using the Ritz-Galerkin method, the eigenvalue equation for a fin line with finite metallization thickness as well as a longitudinal slit in the metal waveguide mount is derived. The numerical solution converges very rapidly in all the cases investigated. Experimental checks are reported, which verify the results of this method and stress the importance of the effects of the finite metallization thickness and longitudinal slit in the mount at higher frequencies. The theoretical results are compared with results by Hofmann, and they are found to correspond closely.     

Investigations of complex modes in a generalized bilateral finlinewith mounting grooves and finite conductor thickness

A generalized bilateral finline with mounting grooves and finite conductor thickness is analyzed by a full-wave mode-matching method. The final nonstandard eigenvalue equation is derived from the unknown coefficients in the slot regions to reduce the size of the matrix equation. The convergence studies of the mode-matching method is first studied for the fundamental mode of a symmetric bilateral finline. Both the propagation constant and the characteristic impedance as defined by the power-voltage relationship are analyzed and compared to the existing data. Excellent agreement is obtained. The effects of metallization thickness and mounting grooves are discussed. The accurate results obtained for the fundamental mode by the mode-matching method with respect to both relative and absolute convergence were also obtained for the complex modes of the finline. The dispersion characteristics of the fundamental, higher order, evanescent, and complex modes are presented for an asymmetric bilateral finline. The effects of mounting grooves and metallization thickness on the complex mode propagation constants are investigated and discussed     

Asymmetrical coplanar waveguide with finite metallization thicknesscontaining anisotropic media

The spectral-domain approach (SDA) is extended to symmetrical and asymmetrical coplanar waveguides with anisotropic media. The quasi-static and hybrid-mode analytical methods are developed in the spectral domain taking the metallization thickness effect into consideration. Numerical computations include the quasi-static and frequency-dependent hybrid-mode values of the phase constants and characteristic impedances for the symmetrical and asymmetrical CPWs and metallization thickness effects in CWPs. Increased metallization thickness significantly reduces the nonreciprocal properties in CPWs with magnetized ferrite and additional dielectric layers     

Feature size limit of liftoff metallization technology

The feature size limits for liftoff metallization technology are evaluated both experimentally and by computer simulation following Blech's model. The mechanism producing a smoothly sloped metallization pattern profile was also clarified. The simulation reveals that the average slope angle of the metallization pattern sidewalls is determined by the reverse mask topology, metallization thickness, and the maximum incident angle of the evaporation system used for the metallization deposition. Simulation results showed good coincidence with experimental results. It is shown that the average slope angle can be controlled between 20° and 70° with polyimide liftoff technology. Feature size limit, i.e., the minimum pitch of metallization patterns, is determined by the reverse mask topology and the maximum incident angle as well as by mechanical and chemical properties of the polyimide layer, but is independent of metallization thickness. In a sample application of the technology in the fabrication of interconnections on rugged LSI surfaces, the minimum pitch of the polyimide liftoff metallization patterns was estimated to be 2.6 µm.     

Feature Size Limit of Liftoff Metallization Technology

The feature size limits for liftoff metallization technology are evaluated both experimentally and by computer simulation following Blech's model. The mechanism producing a smoothly sloped metallization pattern profile was also clarified. The simulation reveals that the average slope angle of the metallization pattern sidewalls is determined by the reverse mask topology, metallization thickness, and the maximum incident angle of the evaporation system used for the metallization deposition. Simulation results showed good coincidence with experimental results. It is shown that the average slope angle can be controlled between 20/spl deg/and 70/spl deg/ with polyimide liftoff technology. Feature size limit, i.e., the minimum pitch of metallization patterns, is determined by the reverse mask topology and the maximum incident angle as well as by mechanical and chemical properties of the polyimide layer, but is independent of metallization thickness. In a sample application of the technology in the fabrication of interconnections on rugged LSI surfaces, the minimum pitch of the polyimide liftoff metallization patterns was estirriated to be 2.6 /spl mu/m.     

Accurate Hybrid-Mode Finline Configurations Including Analysis of Various Multilayered Dielectrics, Finite Metallization Thickness, and Substrate Holding Grooves

An accurate analysis of various finline configurations is introduced. The method of field expansion into suitable eigenmodes used considers the effects of finite metallization thickness as well as waveguide wall grooves to fix the substrate. Especially for millimeter-wave range applications, the propagation constant of the fundamental mode is found to be lower than by neglecting the finite thickness of metallization. For increasing groove depth in cases of asymmetrical and "isolated finline," higher order mode excitation reduces the monomode bandwidth significantly. In contrast to hitherto known calculations, this parameter only causes negligible influence on a fundamental mode if the groove depth is lower than hall of the waveguide height.     

The influence of metallization thickness on the characteristics ofcascaded junction discontinuities of shielded coplanar type transmissionline

A full-wave analysis based on the mode-matching technique is applied to analyze cascaded junction discontinuities of coplanar-type transmission lines, coplanar waveguide (CPW) and finline. Results for a CPW-finline transition, a shielded CPW gap and a symmetric notch incorporating the finite metallization thickness effect are presented. The influence of metallization thickness on the coupling effect exhibited by cascaded junction discontinuities is also presented and discussed     

Effects of the Thin-Film Metal Ground Embedded in On-Chip Microstrip Lines

This letter studies the influence of embedded thin-film metallization layers, normally designed as ground planes, upon the dispersive characteristics of multilayer microstrip lines. The spectral domain approach is used to analyze the effects of the metallization thickness as a design parameter in two structures: the thin-film microstrip line and metal-insulator-metal-insulator line. Numerical results indicate that the thin metallization layer can excite the slow-wave mode and change significantly the dispersive characteristics. Moreover, at low frequencies a local minimal attenuation can be achieved with certain metallization thickness. Thus, it is necessary to take into account this thin-film metal ground to achieve reliable numerical simulation from dc to millimeter-wave frequencies     

The application of the point matching method to the analysis ofmicrostrip lines with finite metallization thickness

The characteristics of a shielded microstrip line with finite metallization thickness are calculated using the point matching method (PMM). The advantage in this case is that the method does not depend on a special geometry of the strip metallization. The approach used is based on satisfying the boundary conditions at discrete boundary points. Numerical results are presented to assert the validity of this approach in cases of large values of strip width-to-thickness ratio. It is found that an increase in the strip thickness is always associated with difficulties in convergence. The examples presented call attention to the necessity of proving the validity of the obtained solutions by other criteria. This is because good convergence behavior of the effective dielectric constant does not always guarantee the correct characteristic impedance or field distribution. In particular, the field distribution is considered as a reliable check for the numerical results     

氧化铝陶瓷金属化技术的研究进展

综述了Al2O3陶瓷金属化技术的国内外研究现状与进展,简要介绍了目前主要应用的几种金属化方法,并着重分析了真空溅射镀膜金属化技术中薄膜材料、膜层厚度以及工艺参数对金属化质量的影响。     

The influence of finite conductor thickness and conductivity onfundamental and higher-order modes in miniature hybrid MIC's (MHMIC's)and MMIC's

The effect of finite metallization thickness and finite conductivity on the propagation characteristics of conductor-backed CPW on thin substrate is rigorously analyzed. A self-consistent approach is used together with the method of lines (MoL) to determine the propagation constant, losses and field distribution of the fundamental and first two higher-order modes in coplanar waveguides (CPWs) with finite metallization thickness and lossy backmetallization. The method used is general and can be applied to miniature MHMICs and MMICs including lossy semiconductor substrate. It is shown that the onset of higher-order modes limits the usable frequency range of conductor-backed CPWs. The analysis also includes microstrip transmission lines on thin substrate material. It is demonstrated that a resistive strip embedded into the microstrip ground plane may potentially be useful in the design of integrated planar attenuators     

An efficient method for computing the capacitance matrix ofmulticonductor interconnects in very high-speed integrated circuitsystems

A new method for computing the capacitance matrix of multiconductor interconnects with finite metallization thickness is developed. Converting the vertical wall of the rectangular conductors into the equivalent horizontal strips allows the Green's function in the spectral domain and the FFT algorithm to be used, which makes the method more effective for computing capacitance matrix of the interconnects     

Solder thickness variation with respect to soldering parameters

This study investigated the growth behavior of solder interconnect on solder bonding pad. The solder thickness was investigated with respect to parameters including bonding pad area, reflow temperature, solder paste volume, loading, and die size (metallization area). Solder thickness was found to have a maximum value with respect to the ratio of solder paste volume to pad size. Loading and the reflow temperature showed no effect on solder thickness. An enlargement in metallization area reduces the solder thickness, while greater solder paste volume increases the solder thickness