Quasistatic characteristics of microstrip on arbitrary anisotropic substrates

An analytical approach is used to find the upper bounds of microstrip line capacitance which arbitrary anisotropic substrate. General expressions are obtained for the permittivity and the thickness of an equivalent isotropic substrate. The method is used to compute the upper and lower bounds parameters of microstrip on sapphire substrate.     

单轴媒质基底上微带贴片的解析渐进提取法

利用解析渐进提取法分析了单轴媒质基底上的微带贴片问题,计算结果表明:和传统方法相比,提出的方法可以提高计算精度的同时,又大大地缩短了计算时间.     

Propagation characteristics of microstrip transmission line on ananisotropic material ridge

A microstrip transmission line residing on an electrically anisotropic material ridge embedded in a multilayered environment is studied using a coupled set of integral equations (IE's). The full-wave IE formulation easily accommodates arbitrary material anisotropy and inhomogeneity in the finite ridge region using equivalent polarization currents residing in a multilayered isotropic background. New results are presented for uniaxially anisotropic ridge structures which show that the transmission line propagation constant is sensitive to anisotropy for certain ridge structures and insensitive for others, compared to the conventional line on an infinite substrate. Results are also presented for a transmission line printed on a nonreciprocal solid-state magnetoplasma ridge. The current distribution associated with the dominant microstrip mode is investigated, where it is found that the transverse component of current is much larger for the ridge geometry than for the infinite substrate case, although the transverse component is still small compared to the longitudinal component     

Lumped capacitance and open end effects of striplike structures inmultilayered and anisotropic substrates

An accurate calculation of the lumped capacitance of a rectangular microstrip patch and the edge capacitance of an open-circuit microstrip or stripline is carried out. Variational expressions in the spectral domain are developed to analyze these conductors when they are embedded in a multilayered anisotropic substrate. A recurrence algorithm, easy to compute, is proposed to determine the three-dimensional spectral Green's function characterizing the sort of substrates employed. The method makes it possible to study biaxial substrates in the case of the rectangular patch and uniaxial substrates with tilted optical axis in the transverse plane in the case of open-circuit striplike transmission lines. A detailed study of trial functions to approximate the charge density on the conductors is carried out, taking into account the physical features of each problem. The results obtained are compared with those appearing in the literature. Original design graphs are presented, with special emphasis on the use of inhomogeneous and anisotropic substrates     

Improved coupled-mode theory for reciprocal anisotropic waveguides

An improved coupled-mode theory for a reciprocal anisotropic multiwaveguide system is derived. The general reciprocal anisotropic medium is described by a symmetric permittivity tensor that can have nonzero off-diagonal elements. The derivation is based on the generalized reciprocity relation. The coupled-mode equations are applicable to both lossy (gain) and lossless systems. For the special case of lossless systems, it is shown that the matrices in the coupled-mode equation are Hermitian, so that energy conservation is observed exactly. For the special case of a single anisotropic waveguide, the results also reduce to the previously derived solutions by D. Marcuse (1975). The improved coupled-mode theory in an anisotropic multiwaveguide system is illustrated with numerical examples     

使用各向异性导电胶实现封装叠加的方法

文章阐述了一种新型的基底结构,通过使用各向异性导电胶来连接两层基底,从而实现封装叠加。这种基底结构来源于一种传统的折叠基底结构,不同的是,它采用各向异性导电胶代替折叠基底结构中的弯曲区域来实现两层基底的电路和物理连接。折叠基底结构中的弯曲区域是一个弱点,其本身存在很高的断裂几率,需要大量冗余线路支撑来提高物理强度。新的基底结构不但降低了断裂几率,消除了冗余线路,而且拓广了适用性并降低成本。     

Propagation Characteristics of Striplines with Multilayered Anisotropic Media

Various types of striplines with anisotropic media are analyzed. The analytical approach used in this paper is based on the network analytical method of electromagnetic fields, and the formulation process is straightforward for complicated structures. Some numerical results are presented and comparison is made with the results available in the literature.     

An anisotropic thermal-stress model for through-silicon via

A two-dimensional thermal-stress model of through-silicon via (TSV) is proposed considering the anisotropic elastic property of the silicon substrate.By using the complex variable approach,the distribution of thermalstress in the substrate can be characterized more accurately.TCAD 3-D simulations are used to verify the model accuracy and well agree with analytical results (＜ ±5％).The proposed thermal-stress model can be integrated into stress-driven design flow for 3-D IC,leading to the more accurate timing analysis considering the thermal-stress effect.     

Hybrid Mode Analysis of Microstrip Lines on Anisotropic Substrates

A rigorous hybrid mode analysis is applied to microstrip lines on anisotropic substrates to determine its high-frequency performance. The analysis is based on a general formulation of the problem of planar transmission lines on multilayered substrates with uniaxial anisotropy, of which the microstrip line is a special case. Exact solution is obtained using a functional equation technique which was previously developed and applied to microstrip and bilateral finlines. The results were used to check the validity of the concept of equivalent isotropic substrate, suggested by some authors to simplify the calculation of the parameters of these lines. Certain approximations are introduced to allow the efficient calculation of the characteristics of microstrips on anisotropic substrates at relatively high frequencies or for wide strips. Numerical results are given for some values of the parameters of microstrip lines on sapphire and include the regions of excitation of higher modes.     

反常涡旋光束在各向异性大气湍流中的漂移

为了研究部分相干反常涡旋光束在各向异性大气湍流中的漂移特性,基于各向异性非Kolmogorov大气湍流谱模型,利用几何光学近似与Rytov近似解得到了部分相干反常涡旋光束(PCAVB)在各向异性湍流中传输的光束漂移解析式,并对该漂移解析式进行数值模拟.研究了拓扑荷、相干长度、各向异性因子、折射率结构常数等光束参量及湍流...     

Closed-form solutions for one-dimensional inhomogeneous anisotropicmedium in a special case. I. Direct scattering problem

An analytical formulation is presented for the direct scattering problem of one-dimensional (1-D) inhomogeneous anisotropic medium in a special case. This method gives nonlinear differential equations for the reflection coefficients of the anisotropic medium. Applying the discontinuity condition of the dielectric parameters at the interface of the medium with free space, approximate closed-form solutions for the reflection coefficients are obtained. Numerical examples show the validity of the method     

Modal Analysis of Microstrip Antenna on Fiber Reinforced Anisotropic Substrates

In this communication, microstrip antenna on fiber reinforced anisotropic substrates has been considered in aerospace applications; however, the antenna's optical axis may not necessarily be colinear with any of the substrate's principal axes and that leads to a nondiagonal permittivity matrix (tensor). This work extends the studies of microstrip antenna on isotropic substrate and on uniaxial substrate to analyze antenna performance on fiber reinforced anisotropic substrates, where the permittivity matrix has five dielectric constants because of the substrate's fiber direction. The solution is based on modal analysis so that the wave immittance can be derived in a closed form. Analyses and experimental verification show that the antenna performance is strongly influenced not only by the permittivity along the principal axes but also by the fiber direction of the substrate.     

A two-dimensional analytical threshold voltage model for MOSFET's with arbitrarily doped substrates

A threshold voltage model is presented which is valid for short- and long-channel MOSFET's with a nonuniform substrate doping profile. The model is based upon an approximate two-dimensional analytical solution of Poisson's equation for a MOSFET of arbitrary substrate doping profile which takes into account the effect of curved junctions of finite depth. The analytical model is compared to MINIMOS simulations showing that it can accurately predict short-channel threshold voltage falloff and threshold voltages in this vicinity without the use of fitting parameters.     

Anisotropic permittivity and attenuation extraction frompropagation constant measurements using an anisotropic full-wave Green'sfunction solver for coplanar ferroelectric thin-film devices

In this paper, a full-wave spectral-domain integral-equation technique is used to study double substrate layer coplanar devices with the ferroelectric thin film adjacent to the conductor guiding interfacial surface. The Green's function is used in the anisotropic situation for anisotropic permittivities. In examining specific laboratory data, going from an unbiased static electric field to the biased case, the permittivity tensor is allowed to go from a unity tensor to a uniaxial one. Consistent with this permittivity tensor behavior, the attenuation trend with frequency and its amplitude is also found     

Three-dimensional scattering by an infinite homogeneous anisotropic circular cylinder: A spectral approach

A set of two coupled integral equations based on a plane wave representation Of the fields in a simply connected and anisotropic medium has been derived in order to handle the problem of scattering by a homogeneous anisotropic cylinder for an obliquely incident plane wave of arbitrary linear polarization. The unknowns are scalar, the range of integration is finite, and the kernels are not singular. Numerical results are presented and discussed in detail. The gyrotropic type case is emphasized, and it is found that as in the isotropic case, the depolarization is the same for transverse electric (TE) and transverse magnetic (TM) incident waves.     

A Microstrip Thin-Film Low-Field Magnetic Transducer

The design of a planar low-field magnetic transducer is suggested. The transducer is based on an irregular ring microstrip resonator with an anisotropic magnetic film. The performance of the transducer is considered in the quasi-static approximation. The use of a high-permittivity substrate and high pumping frequencies provides small sizes of the device. Detection of signals at the eigenfrequencies of the first two oscillation modes of the microstrip resonator makes it possible to determine both the magnitude and the direction of an in-plane magnetic field. Experimental and theoretical data are in good agreement.     

Parameter reconstruction of materials with off-diagonal anisotropy using the state transition matrix method

An effective non-iterative method is developed for determination electromagnetic parameters of complex materials with anisotropy. Unlike the existing methods, the proposed method can extract the electromagnetic tensor parameters of materials with off-diagonal anisotropy using co- and cross-polarized reflection and transmission without using iterative procedures. Useful analytical expressions are derived for extracting the medium parameters of materials with off-diagonal anisotropy. The advantage of the method is that it uses state transition matrix and its properties in order to avoid nonlinearity and complexity of the problem. The method can work very well for dispersive materials since it is based on frequency-by-frequency extraction. The proposed method is validated by extraction of the complex permittivity and permeability tensors of two typical anisotropic materials.     

Analysis of slotlines and microstrip lines on anisotropicsubstrates

The propagation characteristics of the dominant mode in slotlines as well as in microstrip lines on anisotropic substrates are studied. The dielectric tensor in the substrate may have nondiagonal elements which represent misalignment, on the substrate surface, between the material coordinate system and the waveguide coordinate system. The analysis is devoted to the slotline and is based on Galerkin's method applied in the spectral domain. Numerical results are presented for a sapphire substrate and a boron nitride substrate. It is found that the coordinate misalignment on the substrate surface has a significant influence on the propagation characteristics of the slotline     

Characteristics of Single and Coupled Microstrips on Anisotropic Substrates

In this paper, the effect of an anisotropic substrate on the characteristics of covered microstrip is presented for single and coupled lines. The Green's function is obtained in integral and series form for an arbitrary anisotropic substrate. Computer programs based on the method of moments approach [1], [2] are employed and results are presented in graphical form for impedance Z, coupling constant K, and phase velocity v/sub p/ as functions of n/sub x/ / n/sub y/ (the ratio of the substrate indices of refraction). Z, K, and v/sub p/ are studied for various w/H, S/H, and B/H ratios where w is the line width (w/sub 1/ and w/sub 2/ for coupled lines), S is the separation between coupled lines, B is the separation between ground planes, and H is the substrate thickness.     

Microstrip Dispersion Including Anisotropic Substrates

A perturbation-iteration solution based on potential theory is developed for determining the effective dielectric constant, characteristic impedance, and current-charge distribution on a microstrip transmission line with isotropic and anisotropic substrates. The numerical implementation of the theory is described and is suitable for use on a personal computer. Computed data for several common substrate materials are included.