有耗介质导波结构的高次杂交四边形边缘元分析

本文提出了一种高次杂交四边形边缘元方法。讨论了这种高次杂交边缘元的有限元空间构造，给出了其形函数的显形表达式。这种方法不仅消除了伪解而且能直接求解传播常数，从而无需迭代便能分析有耗介质导波结构的传输特性。对矩形导和条形介质填充波导本征模传播常数的计算表明这种高次杂交边缘元的计算精度比低次杂交边缘元要高出一个量级。     

四分量二维紧凑格式频域有限差分方法对粗糙导体表面导波结构的分析

文章利用四分量紧凑格式的二维频域有限差分方法（2-DFDFD）,结合等效表面阻抗边界条件（SIBC）,对粗糙导体表面导波结构的传输特性进行数值分析。根据等效表面阻抗边界条件,可以方便地计算边界上的切向场。只要求出本征方程,在给定频率上的传播常数就可以作为其特征值而被求得。     

准平面多导体耦合线的直线法全波分析

本文提出了一种准平面多导体耦合线的直线法全波分析方法,包括分析多导体耦合线的各个本征模的传播常数、衰减常数、特性阻抗和2N口网络S参数。由于考虑了色散和损耗,本方法将适合于微波频段高端和毫米波段的应用,为微波毫米波集成电路的设计提供了一个实用工具。     

多层手征介质填充圆波导的分析

本文利用递推本征函数法分析了多层手征介质填充圆波导的传播特性.文中给出了不同介质层中电磁场的递推关系,推导了N层手征介质填充圆波导色散特性的一般性计算公式.作为示例,文中还给出了对几种结构传播特性的计算结果.     

多手征介质填充圆波导的分析

本文利用递推本征函数法分析了多层手征介质填流圆波导的传播特性。文中给出了不同介质层中电磁场的递推关系，推导了Ｎ层手征介质填充圆波导色散特性的一般笥计算公式。作为示例，文中还给出了对几结构传播特性的计算结果。     

基于准椭圆函数响应的超宽带介质滤波器设计

设计、分析并制作了工作于S波段的超宽带介质滤波器。滤波器采用三角元件级联(CT)式耦合拓扑结构,利用圆柱体金属同轴作为谐振单元,周围填充介质,通过各谐振器间的耦合系数的计算与仿真,设计出一种具有多个传输零点的准椭圆函数响应介质滤波器。测试结果表明,该滤波器相对带宽达到70%,通带外产生3个传输零点,具有良好的滤波特性,从而证实了本文中方法的正确性和实用性。该滤波器具有插入损耗小、带内回波损耗高、良好的带外抑制特性以及小型化设计等优点,在航空、航天领域中具有良好的应用前景。     

微带耦合弯曲线的本征模和像阻抗

本文得到了多根微带耦合系统(边带对称,中带均匀相同,最近邻的直接耦合起主要作用)的本征模,推导了λ/4耦合弯曲线的像阻抗和传播常数的解析表达式。给出了三种本征模在真空情况下的模阻抗和在基片情况下的填充因子的数值结果。提出在基片(特别是铁氧体基片)情况下微带波长和阻抗的计算方法。用所得理论来分析X波段和C波段弯曲线型微带铁氧体移相器的阻抗匹配问题,与实验结果十分符合。     

非均匀介质填充波导本征值问题的有限元分析

本文讨论了用有限元法求解非均匀介质填充波导本征值问题的具体过程。给出了有关的计算公式和程序。作为例子,对条形介质填充矩形波导主模场结构的分析和色散特性的计算,获得了与解析解十分一致的结果,从而证实了所述程序的可靠性。     

任意横截面形状非均匀介质波导传输特性的分析

用阶梯近似与边缘元和模匹配相结合的方法分析了一大类任意横截面形状非均匀介质波导的传输特性，将非均匀部分用一系列级联的台阶近似，各台阶用微波多模网络等效，用边缘元方法求得各本地波导的本征值问题后，用模匹配法算 出各微波网络的散射参数，最后通过级联的微波网络求得融洽上非均匀结构的传输特性，由于边缘元方法的通用性，此法可对各种不同横截面形状的非均匀介质波导进行分析。     

求解非均匀平面波导导模的一种新方法

本文给出一种新方法,用多层平板波导逼近非均匀平面波导,借助递推公式用牛顿切线法求解本征值方程,以求出非均匀平面波导导模的传播常数与模场分布。本方法优点在于程序简短通用,计算工作量小,求得结果与精确数值解十分吻合(直至近截止区)。本文给出了各种类型的非对称与对称渐变折射率平面波导的结果。     

Equivalent Transformations for Mixed-Lumped and Multiconductor Coupled Circuits

Distributed circuits consisting of a cascade connection of m -port stab circuits and multiconductor coupled transmission lines are equivalent to ones consisting of cascade connections of multiconductor coupled transmission lines whose characteristic impedances are different from original ones, m-port stub circuits, and an m-port ideal transformer bank. Because of the reciprocity of the circuit, values of transformer ratio must be identified. In the special case of a one conductor transmission line, these equivalent transformations are equivalent to Kuroda's identities. These extended equivalent transformations may be applied to mixed-lumped and multiconductor coupled circuits. By using these equivalent transformations, equivalent circuits and exact network functions of multiconductor nonuniform coupled transmission lines can be obtained.     

Capacitance extraction for electrostatic multiconductor problems byon-surface MEI

In this paper, on-surface measured equation of invariance (OSMEI) method is implemented for capacitance extraction of electrostatic multiconductor interconnect problems. OSMEI uses the same mesh as that in method of moments (MoM), but generates highly sparse matrices rather than a full matrix. In comparison with “standard” MEI which contains a few finite difference (FD) or finite element (FE) mesh layers, the number of unknowns and the computation memory can be saved. For each OSMEI equation in the multiconductor interconnects, a given node on a given conductor is forced into coupling with the few adjacent nodes on conductor itself and the few sampled nodes on other conductors. Thus, the system sparse matrices can be generated. The convergent behavior of the capacitance with the number of the nodes in the OSMEI equations has been widely investigated, Numerical examples of the capacitance extraction for two-dimensional (2-D) and three-dimensional (3-D) multiconductor interconnects show that the computing errors are within 24%. The OSMEI method may become a powerful technique for the more complex interconnect problems     

Coupled-mode formulation of multilayered and multiconductortransmission lines

A novel coupled-mode formulation for multilayered and multiconductor transmission lines is developed. In this formulation, the solutions to the original multiconductor system are approximated by a linear combination of eigenmode solutions associated with the isolated single conductor line located in an appropriate reference dielectric medium. The reciprocity theorem is used to derive the coupled-mode equations. The coupling coefficients are expressed in terms of the simple overlap integrals between the eigenmode fields and currents of the individual conductor lines. As a basic application, the dispersion characteristics of two identical coupled-microstrip lines are analyzed using the proposed coupled-mode theory. It is shown that the results are in very close agreement with those obtained by the direct Galerkin's moment method over a broad range of weak to strong coupling     

Application of Modal Analysis to the Transient Response of Multiconductor Transmission Lines with Branches

An effective method for computing the time-domain response of lossless multiconductor transmission lines with branches in cross-sectionally inhomogeneous dielectric media is presented. Lines of this type are characterized by multiple propagation modes having different velocities. The theory of wave propagation on lossless multiconductor transmission lines with inhomogeneous dielectrics is used to obtain the modal amplitudes on the uniform sections of the line. The scattering matrix for the junction is used to compute the transmitted and reflected waves in the different branches at the junction. Each mode arriving at the junction excites multiple modes in all branches. The method described in this paper identifies all propagation modes in all branches of the line, and leads to the direct physical interpretation of the results. The method is general and can be applied to either partially or completely nondegenerate cases. Experimental results for a six-conductor transmission line with a single branch are found to be in good agreement with the results computed using the described method.     

Double-Sided Parallel-Strip Line With an Inserted Conductor Plane and Its Applications

In this paper, a novel multilayer structure using the double-sided parallel-strip line with an inserted conductor plane is investigated. A conductor plane is inserted into the middle of the substrate of the double-sided parallel-strip line in the proposed structure, which can function as virtual ground to isolate the nonidentical circuits on the top and bottom layers effectively. On the other hand, the conductor plane can be negligible for the identical circuits. Based on the new structure, a dual-band stub can be realized using the isolation characteristic of the conductor plane, where the stub can be treated as a combination of two back-to-back microstrip stubs operating at different frequencies. The common ground of the two microstrip stubs is provided by the inserted conductor plane. For demonstrating this idea, a bandpass filter with two transmission zeros is optimized, fabricated, and tested. The simulated and measured results are presented and show good agreement. The size of this filter is reduced approximately by half, as compared with that of the similar type of microstrip filters.     

A Miniaturized Conductor-Backed Slot-Line Resonator Filter With Two Transmission Zeros

In this letter, a miniaturized planar two-pole microwave filter with two transmission zeros is presented. The building block of this filter is a high-Q double spiral slot resonator backed by a conductor plane. The provision of a float back conductor plane allows vertical integration of this filter with other passive and active RF electronic components usually found in miniaturized wireless transceivers. The conductor plane also provides a coupling mechanism between the input and output of the filter giving rise to transmission zeros. It is shown that the location of transmission zeros can easily be adjusted and significant out-of-band rejection be achieved using only two miniaturized double-spiral resonators. The design procedure and fabrication of a two-pole filter operating at 2.11GHz is demonstrated and a very good agreement between measured and simulated results is shown     

Evaluation of measured complex transfer impedances and transferadmittances for the characterization of shield inhomogeneities ofmulticonductor cables

Besides the knowledge of the primary line parameters per unit length, the determination of the complex transfer impedances and transfer admittances of shielded multiconductor cables is the prerequisite for the calculation of the propagation of disturbing currents on the inner wires of the cable. With a measurement procedure based on triaxial measurement setups using multiconductor transmission line theory for evaluation, it is possible to determine individual transfer impedances and admittances for each inner conductor of a shielded multiconductor cable over a broad frequency range. This paper shows the measurement procedure, the method of evaluation: and from measurement results, the determination of the location and the calculation of the area of single-shield inhomogeneities by the evaluation of measured transfer impedances and transfer admittances     

Time-domain analysis of lossy multiconductor transmission lines based on the Lax–Wendroff technique

Taking advantage of the hyperbolic characteristics of the telegrapher equations, this paper applies the Lax–Wendroff technique, usually used in fluid dynamics, to transmission line analysis. A second-order-accurate Lax–Wendroff difference scheme for the telegrapher equations for both uniform and nonuniform transmission lines is derived. Based on this scheme, a new method for analyzing lossy multiconductor transmission lines which do not need to be decoupled is presented by combining with matrix operations. Using numerical experiments, the proposed method is compared with the characteristic method, the fast Fourier transform (FFT) approach, and the Lax–Friedrichs technique. With the presented method, a circuit including lossy multiconductor transmission lines is analyzed and the results are consistent with those of PSPICE. The nonlinear circuit including nonuniform lossy multiconductor transmission lines is also computed and the results are verified by HSPICE. The proposed method can be conveniently applied to either linear or nonlinear circuits which include general transmission lines, and is proved to be efficient.     

S 波段高性能微型滤波器的研究

应用LTCC多层耦合带状线谐振器和交叉耦合传输零点原理,在改进的三维梳状带通滤波器结构中引入交叉耦合,增强非相邻谐振级间的交叉耦合;在2、4谐振级间引入Z字形导体层,通过调节Z字形控制传输零点位置;同时适当调节加载电容大小,有效减小了滤波器体积,实现了高次谐波抑制、边带陡峭和通带内线性相位.采用低温共烧陶瓷(LTCC)技术设计制作了中心频率为3GHz,通带为200MHz的微型带通滤波器.实验和仿真结果表明,该滤波器的中心频率插入损耗小于2.6dB,阻带抑制高于40dB,边带陡峭,尺寸仅为4.8mm×4.2mm× 1.5mm.成品率高达85％.