Ku波段交叉耦合波导滤波器的精确设计

针对软件优化法设计交叉耦合波导滤波器的耗时性,利用矩形波导设计了Ku波段折叠型交叉耦合滤波器。采用S参数的多项式综合和矩阵消零的方法提取耦合矩阵,设计过程将全波建模和电路模型分析相结合,利用微波CAD软件HFSS分步骤对每个谐振单元及耦合结构进行仿真,以确定其尺寸,避免了对滤波器的软件优化,所得仿真结果与理论值吻合较好。     

一种新型一维微带PBG单元结构

通过对传统二维微带 PBG 结构的研究,针对微带线的传播常数是微带线相对于接地板上周期孔眼的两个主轴的位置和方向的敏感参数而不能根据实际情况任意布线的缺点,提出了一种新型一维微带 PBG(photonic bandgap)单元结构及其等效 L-C 电路模型。本文提出的 PBG 传输线可以应用于微波集成电路中,能够减小电路尺寸,且可以抑制高次谐波的产生。     

耦合型漏泄同轴电缆传输和耦合特性研究

针对泄漏同轴电缆作为分布式传感器应用于物联网和智能家居的室内安防入侵检测时，运用全波仿真软件HFSS不能有效仿真长距离的耦合漏缆的问题，提出了一种等效电路模型.利用参数提取软件，先提取单个开槽的缝隙单元的等效电路模型，然后借助于传输线理论，利用四个传输矩阵级联得到整段漏泄同轴电缆的传输矩阵.并考虑两根漏缆缝隙间相互耦合，提出了表征耦合特性的等效电路模型.将等效电路模型利用商用软件高级设计系统（advanced design system，ADS）进行电路搭建与仿真.仿真结果表明，本文提出的两根漏缆的等效电路模型与全波仿真结果非常符合，可以快速地仿真长距离的耦合漏缆结构，并大大节约了仿真时间.     

基于空间映射法的微带滤波器设计方法

针对传统全波电磁仿真工具耗费的时间成本和硬件资源高、电路仿真软件无法保证设计精度的问题,提出一种基于空间映射法的微带滤波器设计方法。首先使用电路仿真软件建立滤波器模型,优化电路模型,快速得到电路模型理想值;然后通过全波仿真软件建立相应模型,仿真得到响应结果,将该结果代入电路模型中,通过建立误差函数优化电路模型,使其响应接近于全波仿真响应,通过对比此时的电路模型与理想电路模型,推断得到全波仿真模型的优化方向。此方法无需扫参,大大减少了全波仿真次数,快速得到全波仿真模型最优解。利用该方法设计一款X频段微带滤波器,实测通带内插损小于1 dB,回波损耗小于-14 dB,进而验证了该方法的有效性。     

交叉耦合滤波器设计与传输零点的独立性分析

对具有陡峭带外特性的交叉耦合滤波器进行了分析,以四腔交叉和三腔交叉耦合形式作为单元电路,发现了相连时各节电路的带外传输零点各自独立,这一特点使得这种结构的滤波器容易调节,通过实例证明了该操作的可行性和正确性。采用发夹式微带线结构进行滤波器设计,同时运用全波电磁分析软件,对滤波器进行了仿真、优化并对其结果作了讨论分析。     

铁磁性基体与金属线阵列复合体系的双负材料特性

基于铁磁性基体与金属线阵列复合结构等效电磁参数的长波近似模型,设计了一种应用铁磁性基体的二维双负材料。根据带有介质包裹层的金属线的散射特性,采取多重散射方法计算了铁磁性基体与金属线阵列复合结构的传输谱;还通过全波仿真提取了单元结构的等效电磁参数。这些数值结果与长波近似模型的理论结果取得了很好的一致,确认了该模型的正确性。通过仿真周期复合体系中的电磁场分布,在所设计的双负频带内观察到了反向波现象,进一步验证了所设计的复合体系的双负特性。     

同轴腔带通滤波器的一种设计方法

采用负阻线子网络…构造了多腔耦合的同轴带通滤波器电路模型，应用电路分析软件对滤波器进行了分析优化，得到腔体之间耦合系数和接入点位置。应用三维全波分析软件，分析了腔体结构参数与耦合系数和耦合窗的关系。以这种路和场的仿真、优化相结合的方法，得出了滤波器的耦合和输入输出结构参数。运用该方法设计的中心频率2．4GHz，通带100MHz的六腔滤波器的实际测试结果与仿真分析结果基本一致。     

微波电路通孔结构的改进型矩阵束矩量法仿真

对多层微波电路通孔结构进行RWG片元建模,用矩量法求解通孔表面电流,并运用矩阵束方法提取通孔外部结构相关参数,进一步得到20GHz以内散射参数。为提高求解速度,应用了等效介电常数和高效的矢量化运算,大幅度地提高了算法的效率。通过与全波仿真软件HFSS对比,验证了算法的正确性和高效率。另外加工了一套电路板进行实验测试,实测结果与本文算法计算基本吻合,说明了算法的可靠性。     

高速电路倒装互连结构的不连续性分析

针对倒装互连结构的不连续性,建立了各部分结构的解析式,结合等效电路以及全波仿真模型,利用仿真软件进行电路参数提取,解释了连接器件各个部分的物理意义,研究了封装的寄生参数对器件的影响。对于高速互连结构中普遍的不连续性,如焊点和传输线互连处等的信号特性进行仿真。可以找出有效的模型改进参数,使结构得到优化。应用仿真结果确定实验测试的方法,在保证模型特性的前提下,有效地降低了实验成本。最后对仿真结果进行了实验验证,并且有较好的一致性。     

CRLH-TL激励源的设置和S参数的提取计算

该文使用两种全波分析法对传统的带阻滤波器和一维复合左右手传输线(Composite Right/left-handed Transmission Line CRLH-TL)进行了数值分析,解决了多端口激励源的设置和多端口S参数提取的两大难点,计算结果分别与FEKO和电路模型等效法的分析结论进行了比较,吻合较好;并通过增加CRLH单元数得出电路模型等效法的不足,不仅验证了此激励源设置和S参数提取的正确性,也得出了CRLH-TL不同于传统右手传输线的一些左手特性,为分析、优化CRLH传输线以及CRLH漏波天线提供了一定的理论支持。     

An Equivalent Feed Model for the FDTD Analysis of Antennas Driven Through a Ground Plane by Coaxial Lines

For the finite-difference time-domain (FDTD) analysis of antennas excited by coaxial lines, an equivalent model of the antenna feed is presented here. Under the quasi-static approximation, the coaxial aperture is simply represented as the equivalent magnetic-frill current and the equivalent load circuit including the effects of the coaxial line. It leads us to a simple modification of the standard FDTD update equation at the aperture without any additional cell modeling of the line. The validity of the proposed model is confirmed by comparing of the FDTD results and the measured data.      

Influence of a metallic enclosure on the S-parameters of microstripphotonic bandgap structures

Planar microstrip photonic bandgap (PBG) structures are periodic arrays of holes etched in the ground plane of a conventional microstrip line. Most of the published studies considered the PBG as an unshielded structure. However, to fabricate a circuit with a PBG structure, a metallic enclosure is often needed. Thus, the S-parameters of the PBG structure will be altered correspondingly. In this paper, the influence of the metallic enclosure on a shielded PBG structure as well as the finite ground plane on an unshielded PBG structure on the S-parameters are analyzed using the finite-difference time-domain (FDTD) method. Conditions for which the influence can be neglected are obtained. The results are useful for the applications of PBG structures     

FDTD analysis of high frequency electronic interconnection effects

A full-wave analysis of coupled high-frequency interconnect discontinuities is presented using the finite-difference time-domain (FDTD) method. The electromagnetic effects of two via holes on microstrip lines in close proximity to one another are examined and equivalent circuits are presented. The effects of two adjacent lines with bond wires, used, for example, to connect a die to the leadframe of an integrated circuit (IC) package are also analyzed. Frequency domain results are presented by using the discrete Fourier transform of the time-domain results. Guidelines regarding the effective use of the FDTD code including the use a priori calculated electric field distribution in the excitation plane, and the use of a weighted ϵ_r,eff to minimize reflections at the absorbing boundaries are described. The obtained FDTD results and the developed equivalent circuit models show the importance of radiation effects at frequencies beyond 20-30 GHz, the possibilities of reducing the inductive effect of bond wires by using two parallel bond wires instead of one, and the importance of including mutual inductance elements in the equivalent circuit model to account for the crosstalk between parallel vias across a ground plane     

Analysis of a double step microstrip discontinuity in the substrateusing the 3D-FDTD method

The finite-difference time-domain (FDTD) method has been applied to the analysis of a double step microstrip discontinuity having thickness changes in the longitudinal direction. The discontinuity occurs in patch antenna feeds or interconnections between microwave planar circuit modules. The simulation results are compared with those computed by HFSS to show a good agreement. An equivalent circuit for the double step discontinuity is developed from the scattering parameters computed by the FDTD method     

Directive photonic-bandgap antennas

This paper introduces two new photonic bandgap (PBG) material applications for antennas, in which a photonic parabolic reflector is studied. It is composed of dielectric parabolic layers associated to obtain a PBG material. The frequency gap is used to reflect and focus the electromagnetic waves. This device has been designed using a finite-difference time-domain (FDTD) code. FDTD computations have provided the theoretical reflector's directivity. These results are in good agreement with measurements, and it appears that the PBG reflector presents the same directivity as a metallic parabola. A second application uses a defect PBG material mode associated with a metallic plate to increase the directivity of a patch antenna. We explain the design of such a device and propose experimental results to validate the theoretical analysis     

A simple and analytical parameter-extraction method of a microwaveMOSFET

A simple and accurate parameter-extraction method of a high-frequency small-signal MOSFET model including the substrate-related parameters and nonreciprocal capacitors is proposed. Direct extraction of each parameter using a linear regression approach is performed by Y-parameter analysis on the proposed equivalent circuit of the MOSFET for high-frequency operation. The extracted results are physically meaningful and good agreement has been obtained between the simulation results of the equivalent circuit and measured data without any optimization. Also, the extracted parameters, such as g_m and g_ds, match very well with those obtained by DC measurement     

A time-domain full-wave extraction method of frequency-dependentequivalent circuit parameters of multiconductor interconnection lines

A time-domain full-wave method for the extraction of frequency-dependent equivalent circuit parameters of multiconductor interconnection lines is presented in this paper. The circuit parameters extracted by this method can be inserted into circuit simulation software to investigate time-domain responses of a high-speed IC system with multiconductor interconnects. Because the definitions of the voltage and the current are not unique in full-wave analysis, transformation among circuit parameters according to different definitions of the voltage and current is also presented. The method is based on the finite-difference time-domain (FDTD) method, and the reliability of this method is illustrated by its application to representative problems     

Transient propagation in anisotropic laminated composites

A detailed analysis of the transient response of an electromagnetic pulse (EMP) and a Gaussian pulse in anisotropic laminated composites is presented. To this end, both the equivalent transmission line circuit (ETLC) model and the finite-difference-time-domain (FDTD) method are adopted in the time-domain analysis. Numerical results are presented for graphite/epoxy laminates, based on a model which treats each lamina as a homogeneous and anisotropic sheet. The factors that influence the transient response of anisotropic laminated composites, such as laminate thickness, fiber orientation, and the angle, frequency contents, and polarization of the incident wave, are also investigated