DESIGN OF A NOVEL 2-D UNIPLANAR CRLH-TL STRUCTURE

A novel uniplanar 2-D composite right/left-handed transmission line (CRLH-TL) structure is proposed based on a general transmission line theory and the way to increase the relative operating bandwidth in the left-handed (LH) region and lower the LH operating frequency is illustrated. In addition, a new method to extract parameters and calculate the Bloch impedance of the structure is presented. Numerical results of the dispersion as well as the extracted parameters are given, which are calculated based on full-wave simulation. The present 2-D uniplanar CRLH-TL structure is applicable to 2-D left-handed materials in lower and wider LH frequency range.     

FDTD法分析高速集成电路芯片内互连线

本文首次利用时域有限差分(FDTD)法分析了高速集成电路芯片内半导体基片上的有耗互连传输线的电特性.文中提出了有耗吸收边界条件,推导了不同媒质交界面上的边界条件通用格式.在FDTD分析的基础上,得到传输线各种参数的频变特性,为芯片内电路模拟提供了可靠的参数.     

基于多开口谐振环的双频左手材料设计

基于多开口谐振环结构,提出一种双频宽带左手材料.结构由正方形谐振环与工字型负载线组合而成,具有频带宽、频率可调与易于加工的特点.通过软件仿真与样品测试提取等效介质参数,结果表明该结构左手频带分别位于7.8~8.2 GHz和8.4~13.4 GHz,左手带宽共计5.4 GHz.相较于传统结构,该结构带宽更宽且在一定范围可对左手频带进行调节.     

Modeling and analysis of vias in multilayered integrated circuits

A method for modeling and analyzing vias the multilayered integrated circuits is presented. The model is based on microwave network theory. The whole via structure is divided into cascaded subnetworks, including a vertical via passing through different layers and transitions from the microstrip line and/or striplines to the vertical via. The parameters of each subnetwork are obtained from electromagnetic field analysis. Numerical results in the frequency domain and the time domain are presented. Validation of the model has been carried out by both measurements and finite-difference-time-domain (FDTD) modeling. The results show good agreement with the measurements in the frequency range for which the components of the experimental model are within specification. The time domain simulation results also agree well with the FDTD results     

Equivalent circuit modeling of losses and dispersion in single andcoupled lines for microwave and millimeter-wave integrated circuits

Losses and dispersion in open inhomogeneous guided-wave structures such as microstrips and other planar structures at microwave and millimeter-wave frequencies and in MMICs (monolithic microwave integrated circuits) have been modeled with circuits consisting of ideal lumped elements and lossless TEM (transverse electromagnetic) lines. It is shown that, given a propagation structure for which numerical techniques to compute the propagation characteristics are available, an equivalent circuit whose terminal frequency and time-domain properties are the same as the structure can be synthesized. This is accomplished by equating the network functions of the given single or coupled line multiport with that of the model and extracting all the parameters of the equivalent circuit model by using standard parameters identification procedures. This model is valid over a desired frequency range and can be used to help design both analog and digital circuits consisting of these structures and other active and passive elements utilizing standard CAD (computer-aided design) programs. To validate the accuracy and usefulness of the models, results for a mismatched 50-Ω line in alumina and a high-impedance MMIC line stub are included     

一种基于耦合线和环形微带线的负群时延电路

负群时延电路(NGDC)在微波系统中有着广泛应用,文中提出了一种基于有损耦合线和环形微带线的负群时延电路。该电路由耦合线和微带传输线组成。基于射频领域中偶模-奇模分析方法,分析该电路的偶模和奇模的输入导纳,得到电路的S 参数。利用HFSS 电磁仿真软件对该负群时延电路结构做了优化设计,实物加工并测试。测试结果表明:在中心频率2.36 GHz 时,该电路的负群时延值约为-1.4 ns,插入损耗S21约为-3.9 dB,反射系数S11约为-9.5 dB,实测与仿真结果吻合。这种新颖的负群时延电路结构简单、信号损耗小、易于加工,可用于微波和无线通信等领域。     

Design and calibration of a large broadband dielectric measurementcell

A large dielectric measurement cell was designed and calibrated to operate over a 1-MHz to 3-GHz frequency range. The cell is much larger than commercially available cells and is useful for measuring samples with large-grain heterogeneities like concrete or rock. The cell works on a coaxial transmission line principle. Once the S parameters of the two end sections are calibrated, the S parameters of the sample region can be found. Then the complex permittivity of the sample can be deembedded. Because of the broad frequency range, three calibration methods are used for the low-, intermediate-, and high-frequency ranges. The accuracy of the cell is tested by measuring materials of a known dielectric constant. Error analysis is also performed to determine the uncertainty of the measurements     

Parameters of asymmetrical co-planar striplines with finite substrate thickness

Analytical formulae for the quasi-TEM parameters of an asymmetrical co-planar stripline with finite substrate thickness are obtained from those of the infinite-thickness structure. Their accuracy is verified by a comparison between the calculated and available results for the specially symmetrical case. In addition, these line parameters are calculated approximately by simulating an asymmetrical co-planar line with two symmetrical lines. Good agreement is obtained for a wide range of geometric parameters.     

Analysis and design of microstrip-slot line for phase shiftingapplications

The analysis and design of printed phase shifters based on the microstrip line are described. A spectral-domain analysis is presented where the necessary Green's functions are formulated using the transmission matrix technique. The nonreciprocal characteristics for single-layer and multilayer structures are studied. Microstrip-slot in a multilayer structure of ferrite and high-dielectric material is found to have considerably more nonreciprocity than microstrip-slot for microstrip in a single-layer structure. Over 65°/cm is predicted for certain optimized designs. This, in addition to the 50-Ω design capability of the line, makes the microstrip-slot line a suitable choice for phase shifting applications. A multilayer microstrip-slot line was constructed on a rectangular ferrite toroid. Differential phase shifts of roughly 45°/cm were measured over a 6.0-8.5-GHz frequency range. These results are in good agreement with the analysis     

Extraction of distributed parameters for multi-conductor transmission lines by the difference iteration method

The distributed parameters of the transmission lines have the significant impact to the signal propagation. In the conventional method of the distributed parameter extraction, the discontinuity of inverse trigonometric or hyperbolic can arise the problem about phase ambiguity which causes significant errors for transmission models. A difference iteration method (DIM) is proposed for extracting distributed parameters of high frequency transmission line structure in order to overcome the phase ambiguity in the conventional method. The formulations of the proposed method are first derived for two-conductor and multi-conductor lines. Then the validation is performed for the models of micro-strip transmission line. Numerical results demonstrate that the proposed difference iteration method can solve the problem about the phase ambiguity and the extracted distributed parameters are accurate and efficient for a wide range of the frequencies of interest and line lengths.     

数控可选通微带滤波器组的设计与仿真

设计了宽频带数控可选通微带滤波器组,采用微波开关实现滤波器组的单个选通。分析了电容加载谐振器的谐波特性,每个带通滤波器被设计成梳状线结构,并用先进的设计系统（ADS）优化其结构参数。数控滤波器组由两片带译码器的微波开关芯片和4个微带滤波器构成。仿真结果表明,三位二进制编码控制每个滤波器的通断,可实现500~2 000 MHz频段滤波器的选通。     

光学外差法产生微波信号特性的研究

采用光学外差技术产生微波信号,是利用两个光信号之间的频率差,这个频率差就是微波信号的频率.光信号的一些参数变化会影响产生的微波信号,针对偏振、初相位、谱线宽度等影响因素,进行了深入的理论分析与推导,并对推导的结果进行仿真,得到了随着这些参数的改变导致所产生的微波信号特性的一些变化规律.

Abstract：

A microwave signal produced by optical heterodyne technology is based on the frequency deviation of two optical signals, which is the frequency of the microwave signal. Some optical parameters can affect the generated microwave signal, and for these influencing factors, such as polarization, initial phase, and line width, analysis and derivations are conducted. And the results of the derivation are simulated, and the relationship between the changes of microwave signal and these parameters is obtained.     

Characterization of buried microstrip lines for constructinghigh-density microwave integrated circuits

This paper describes the characterization of a guided wave structure, buried microstrip line (BMSL), which is considered to be promising for constructing high-density microwave and millimeter-wave integrated circuits because of its high isolation characteristics. The BMSL includes a dielectric medium surrounded by ground conductor walls and a strip conductor on the top of the dielectric. The BMSL structure is characterized by the two methods, the rectangular boundary division (RBD) method and the finite-difference time-domain (FDTD) method. The RBD method is employed to obtain basic parameters of the BMSL such as characteristic impedances and coupling coefficients over a wide range of line sizes taking advantages of its high calculation efficiency. On the other hand, the FDTD method has been used for more detailed characterization such as the frequency performances of stub matching circuits. The FDTD method is also used to confirm the validity of the quasi-TEM wave approximation which the RBD is based on. The analysis results reveal that the BMSL structure possesses much lower coupling coefficients than a conventional microstrip line does, from -15 dB to -100 dB depending on their burial depths     

A design of the low-pass filter using the novel microstrip defectedground structure

A new defected ground structure (DGS) for the microstrip line is proposed in this paper. The proposed DGS unit structure can provide the bandgap characteristic in some frequency bands with only one or more unit lattices. The equivalent circuit for the proposed defected ground unit structure is derived by means of three-dimensional field analysis methods. The equivalent-circuit parameters are extracted by using a simple circuit analysis method. By employing the extracted parameters and circuit analysis theory, the bandgap effect for the provided defected ground unit structure can be explained. By using the derived and extracted equivalent circuit and parameters, the low-pass filters are designed and implemented. The experimental results show excellent agreement with theoretical results and the validity of the modeling method for the proposed defected ground unit structure     

Characterization of three-dimensional open dielectric structuresusing the finite-difference time-domain method

Millimeter and submillimeter wave three-dimensional (3-D) open dielectric structures are characterized using the finite-difference time-domain (FDTD) technique. The use of FDTD method allows for the accurate characterization of these components in a very wide frequency range. The first structure characterized through FDTD for validation purposes is a mm-wave image guide coupler. The derived theoretical results for this structure are compared to experimental data and show good agreement. Following this validation, a sub-mm wave transition from a strip-ridge line to a layered ridge dielectric waveguide (LRDW) in open environment is analyzed, and the effects of parasitic radiation on electrical performance are studied. The transition is found to be very efficient over a wide sub-mm frequency band which makes it useful for a variety of applications. In addition to the transition, a sub-mm wave distributed directional coupler made of the LRDW is extensively studied using the FDTD method as an analysis tool. Furthermore, an iterative procedure based on the FDTD models is used to design a 3-dB coupler with a center frequency of 650 GHz and negligible radiation loss. This successful design shows that the FDTD technique can be used not only as an analysis method, but also as a design tool to provide designs which take into account all high frequency parasitic effects     

Comparison of the transmission line and scattering models forcomputing the HEMP response of overhead cables

The author discusses the use of transmission line and electromagnetic scattering models for computing the induced currents on long above-ground electrical cables, subjected to a transient plane wave excitation. The pertinent equations for determining the excitation electric field along the cable are summarized, along with the expressions which relate the line current to the excitation field. For the transmission line case, the cable current can be expressed in terms of per-unit-length impedance and admittance parameters which are functions of only the line geometry and the frequency. For the scattering case, similar line parameters can be inferred from the form of the solution for the current, but with the line parameters depending on the angles of incidence. Several numerical calculations of the line responses are provided, and these indicate that the transmission line analysis appears to provide response estimates which are smaller than those obtained using the more accurate scattering theory     

Parametric Characteristic Analysis for Generalized Frequency Response Functions of Nonlinear Systems

In order to explicitly reveal the relationship between system frequency response functions and model parameters which define system nonlinearities, and consequently unveil a direct connection from model parameters to system frequency response characteristics, a parametric characteristic analysis approach is proposed for Volterra systems described by a nonlinear differential equation (NDE). The parametric characteristics of the generalized frequency response functions (GFRFs) for the NDE model are established, and some important properties are discussed, which can explicitly reveal what model parameters contribute and how these parameters affect the GFRFs. Based on the parametric characteristic analysis, it is demonstrated how the system frequency domain characteristics are related to the system time domain model parameters and how the output frequency response function can now be determined explicitly with a detailed polynomial structure. These new results provide a significant and novel insight into the analysis and design of nonlinear systems in the frequency domain. Several examples are included to illustrate the results.     

Analysis of a double step microstrip discontinuity using generalized transmission line equations

In this paper, a new analysis for a double step microstrip discontinuity is presented by using generalized transmission line equations . The new analysis is based on a new concept of a finite-length transmission line integrated with its double step discontinuity so that the double step discontinuity is regarded as a finite-length nonuniform transmission line and the generalized equations could be directly implemented. Since the generalized equation coefficients are determined by dynamic numerical methods and the coefficients are invariant with the line excitation and load, the equations are dynamic rather than TEM. The interested discoveries are that the generalized equations for the whole double step structure or a partial double step structure can give us the same results and the generalized equations have broadband frequency characteristics. For the double step structure used in this paper for the analysis, the S-parameters for a frequency band from 0.5 GHz to 10 GHz can be well calculated by using only two separately generalized equations at frequency of 3 GHz and 8 GHz.     

Spectral-domain computation of characteristic impedances andmultiport parameters of multiple coupled microstrip lines

A numerical procedure based on the spectral-domain techniques is formulated to compute all the frequency-dependent normal-mode parameters of general multiple coupled line structures in an inhomogeneous medium. In addition to the phase and attenuation constants for all the normal modes, these parameters include the line-mode and decoupled line modal impedances and the current and equivalent voltage eigenvector matrices of the coupled system. The multiport admittance (and impedance) matrices and coupled line equivalent-circuit model parameters are evaluated in terms of these normal-mode parameters. Numerical results for these normal-mode parameters for typical asymmetric two-, three-, and four-line microstrip structures are included to demonstrate the procedure and the frequency dependence of these parameters     

High-frequency characterization of on-chip digital interconnects

On-chip inductance is becoming increasingly important as technology continues to scale. This paper describes a way to characterize inductive effects in interconnects. It uses realistic test structures that study the effect of mutual couplings to local interconnects, to random lines connected to on-chip drivers, and to typical power and ground grids. The use of S parameters to characterize the inductance allows a large number of lines to be extracted while requiring only a small overhead measurement of dummy open pads to remove measurement parasitics. It also enables direct extraction of the frequency-dependent R, L, G, C parameters. The results are summarized with curve-fitted formulas of inductance and resistance over a wide range of line spacings and line widths. The significance of the frequency dependence is illustrated with transient analysis of a typical repeater circuit in a 0.25-μm technology. A model that captures the frequency dependency of the extracted parameters accurately predicts the performance of a new inductance-sensitive ring oscillator