An Ultra-Compact Planar Bandpass Filter With Open-Ground Spiral for Wireless Application

A common via filter is investigated and designed by using a proposed scalable lumped circuit model. The model-based result of the filter agrees well with that of the measurement. An ultra-compact open-ground spiral filter is proposed based on the common via filter. The open-ground spiral resonators are used to design second-order and fourth-order bandpass filters. The filter layouts, which affect filter performance in both passband and stopband, are investigated. The advantages of the open-ground spiral filter include not only its ultra-compact size (only ) but also its additional transmission zero points and controllable stopband.     

Design, Optimization of RF Spiral Inductors Using Scalable Compact and Accurate Models

This paper presents a practical and structured approach to the design and optimization of RF spiral inductors. The accuracy of proposed modified accurate distributed and scalable compact lumped models are quantitatively compared with experimental results. Based on the new scalable compact lumped model, a quality factor optimization engine is verified. The inductors under study include single/double layer inductors, metallization shunted as well as octagonal shaped inductors. Experimental results suggest that the new modified accurate distributed model is more accurate than existing models for predicting spiral inductor performance to even beyond resonance frequencies. In addition, using a self developed optimization engine, the new scalable compact model is sufficiently accurate in determining the optimum inductor geometry. Consequently, a web-based program (SISOP) is developed to provide RF designers total solution to spiral inductor design, optimization and integration of spiral inductor model into their lump circuit simulators.     

Models and Tools for CMOS Integrated Inductors

In this paper we are reporting our research in the development of automatic tools to assist the designers in selecting and automatically laying-out integrated inductors. This task is accomplished by analyzing carefully the lumped equivalent circuit model for these passive components, and using different approaches and modifications depending on the required accuracy and application. As a result modified circuit models for integrated inductors based on the conventional lumped element model are proposed. Model development is based on measurements taken from more than 100 integrated spiral inductors designed and fabricated in a standard silicon process. We show the ability of the proposed models to accurately predict the integrated inductor behavior extending the frequency range where they can be applied as compared with the conventional model.     

单片微波集成电路中集总参数元件模型及其CAD程序

本文给出了带状和螺圈电感、叉指和MIM电容、有源层和金属膜电阻等常用于单片微波集成电路中的集总参数元件的分析模型,编写出了相应的计算机分析与设计程序——SLECAD,并能在1BM PC/XT微机上运行。利用此程序,对业已发表的元件数据以及本所的一些实验数据进行了对照分析计算,取得了相吻合的结果。     

共面波导不连续结构EC-ANN模型的电路设计与实现

将一种精确高效的等效电路训练人工神经网络模型引入共面波导不连续性结构建模.该建模算法继承了等效电路模型和电磁仿真人工神经网络模型的优点.此次开发并得到验证的共面波导不连续性结构模型包括:台阶段、叉指电容、对称十字节和螺旋电感.这些模型嵌入CAD仿真工具可以完成电路的设计、仿真和优化,最后通过一个GaAs工艺的共面波导带通滤波器的设计与实现验证了模型的有效性.     

CAD models of lumped elements on GaAs up to 18 GHz

Lumped elements are considered as very attractive structures for the realisation of MMICs with respect to considerable size-reduction. Improved models for integrable lumped-element straight-line, single-loop, and spiral inductors, as well as for interdigitated and MIM capacitors, have been derived using numerical solutions of the inductance integral, basic microstrip theory, and network analysis. The broad experimental verification shows good agreement between models and experiments, with deviations of 5-10% up to 18 GHz. Besides the practical values and frequency range, losses of the lumped elements are presented     

CMOS RFIC平面螺旋电感的集总等效电路

基于DDM-CM理论,建立了CMOS工艺下射频集成电路中广泛使用的平面螺旋电感器的π型集总等效电路.获得了Si-SiO2结构衬底上解析、封闭的集总参数的表达式,并和已经发表了的实验数据进行了比较,验证了所得结果的准确性.     

Spiral transmission-line baluns for RF multichip module packages

We describe a design method and lumped model for a circular spiral transmission-line balun. All lumped values are extracted from the geometric parameters of the balun. From simulation, the design parameters with well predicted characteristics are defined. The balun is fabricated using multi-chip module processing technology, which is suitable for integration in RF packages. Measurements show a wide bandwidth of 1.5-4.1 GHz and excellent balanced outputs. Amplitude imbalance less than 0.5 dB and phase imbalance less than 4° are achieved. The simulation results are compared with the measurement. The model captures all important properties of the balun with reasonably high accuracy     

硅基平面螺旋电感的等效电路模型和参数提取

针对螺旋电感传统等效电路模型的不足,提出了一种改进形式的集总参数等效电路模型.该等效电路模型能很好地反映出电感参数随频率变化的实际效应,可适用于从低频到自谐振频率的宽频带范围.同时,应用电磁场全波分析方法对CMOS工艺下平面螺旋电感进行仿真分析.从得到的散射参数中提取电感L、Q值及自谐振频率.基于参数优化和曲线拟合技术,给出了等效电路模型中各个元件值的多变量闭合表达式.这些表达式可方便地用于集成电路的设计和优化,从而提高电路设计的性能和效率.     

Synthesis of Reduced Equivalent Circuits for Transmission Lines

This paper presents a method for generating lumped models for symmetrical transmission-line two-ports. These models consist of an ideal transformer and frequency-domain approximations for two physical driving-point impedances. The lumped element values are obtained directly from the distributed parameters or propagation constant and characteristic impedance. The method is applied to dispersive transmission lines, skin effect and waveguides. It is shown that the equivalent circuit is superior in accuracy and number of elements compared to spatial discretizations like ladder approximation.     

Improved planar spiral transformer theory applied to a miniaturelumped element quadrature hybrid

In this paper, an improved method of determining the primary-to-secondary coupling capacitance for planar spiral transformers (PST's) is presented, which enhances previous work. A more general monolithic microwave integrated circuit (MMIC) compatible lumped element multisection model is also presented based on symmetric-width uniformly coupled transmission lines. These techniques were developed to design a 90° hybrid as a MMIC with a center frequency of 2.5 GHz. The design was frequency scaled to 0.5 GHz and fabricated in the microwave integrated circuit (MIC) for verification. Producibility is enhanced and coupling is effectively increased with the novel use of series capacitors which cancel some of the self-inductance of the transformers. Measured results are presented for both a quadrature hybrid and the individual PST used in the quadrature hybrid. The measured results show excellent agreement with the computer models     

An efficient path-based equivalent circuit model for design, synthesis, and optimization of power distribution networks in multilayer printed circuit boards

In high-speed printed circuit boards, the decoupling capacitors are commonly used to mitigate the power-bus noise that causes many signal integrity problems. It is very important to determine their proper locations and values so that the power distribution network should have low impedance over a wide range of frequencies, which demands a precise power-bus model considering the decoupling capacitors. However, conventional power-bus models suffer from various problems, i.e., the numerical analyzes require huge computation while the lumped circuit models show poor accuracy. In this paper, a novel power-bus model has been proposed, which simplifies the n-port Z-parameters of a power-bus plane to a lumped T-network circuit model. It exploits the path-based equivalent circuit model to consider the interference of the current paths between the decoupling capacitors, while the conventional lumped models assume that all decoupling capacitors are connected in parallel, independently with each other. It also models the equivalent electrical parameters of the board parasitic precisely, while the conventional lumped models employ only the inter-plane capacitance of the power-ground planes. Although it is a lumped model for fast and easy calculation, experimental results show that the proposed model is almost as precise as the numerical analysis. Consequently, the proposed model enables a quick and accurate optimization of power distribution networks in the frequency domain by determining the locations and values of the decoupling capacitors.     

Comparison of large signal models for junction transistors

The Ebers-Moll, charge control, and Linvill lumped models are systematically derived from a common mathematical origin. Approximations are discussed in detail, and the models are compared on the basis of their ability to represent physical processes, the ease with which they lend themselves to analysis, and the degree of approximation involved. It is shown that all three models are equivalent with regard to over-all degree of approximation, and therefore yield the same results in the solution of large-signal transient problems. However, the lumped model best portrays physical processes and lends itself most easily to intuitive understanding.     

集总参数电路与磁路、热路的关联性教学

本文采用类比和关联方法,拓展电路中集总参数思想。通过将磁路、热路中相应的物理量与电路中的电流、电势、电阻进行类比和关联,帮助学生理解集总参数模型思想,掌握各物理量的涵义。通过对具体用电设备电动机的简单建模分析,促使学生将集总参数模型在其它电、磁、热的分析中能够融会贯通,应用电路理论所学知识,建立合理的物理模型及分析解决问题。     

Small signal equivalent circuit of unsymmetrical junction diodes at high current densities

Finite difference equation methods and lumped models are applied to the solution of the differential equations for the carrier flow through a quasi-neutral semiconductor bulk region at low, moderate and high injection densities. An unsymmetrically doped diode is approximated by a single section lumped model. The static I-V characteristics for this model at low and high current densities are derived. The small signal equivalent circuit of an unsymmetrically doped diode at high injection densities is presented. Approximations for the elements (R, L, C) of this equivalent circuit are calculated from the single section lumped model. The static characteristic and the small signal equivalent circuit elements are in satisfactory agreements with experimental results for diodes in which the base length is not too long compared to the diffusion length.     

Analysis and design of two-arm conical spiral antennas

The two-arm, conical spiral antenna is analyzed using the finite-difference time-domain method. The analysis is validated by comparison with measurements of the input impedance and the realized gain. A parametric study is performed with the analysis, and the results from the study are used to produce new design graphs for this antenna. These graphs supplement and extend the existing, mainly empirical, design base for this antenna. Two resistive terminations, intended to improve the low-frequency performance, are examined. One is a termination formed from two lumped resistors, and the other is a new termination formed from a thin disc of resistive material. These terminations are shown to improve the front-to-back ratio and axial ratio for the antenna     

A wide-band GaAs monolithic spiral quadrature hybrid and itscircuit applications

The design, performance, and circuit applications of a 2-6-GHz GaAs monolithic spiral quadrature coupler are presented. This 90° coupler uses lumped spiral inductors and metal-insulator-metal (MIM) capacitors and is very small in size (14 mil×26 mil). The measured relative phase difference between the coupled and direct port over the 3:1 bandwidth was 93°±6°. Applications of this broadband hybrid in reflection phase-shifter, image-reject downconverter, and I-Q downconverter circuits have also been successfully demonstrated based on this structure     

On the modeling of highly nonlinear circuits usingtotal-variation-decreasing finite-difference schemes

This paper presents the modeling of highly nonlinear circuits using a total-variation-decreasing (TVD) difference scheme developed for the simulation of problems involving shock phenomena. In contrast to the commonly used leapfrog scheme, a second-order accurate TVD method based on the Lax-Wendroff scheme is applied to one-dimensional nonlinear transient electromagnetic-wave problems. Furthermore, for the analysis of transmission-line-based networks, an adapted inclusion of nonlinear lumped elements in such a TVD scheme is proposed. As an example, both the scattered signals of a linear transmission line loaded with a nonlinear lumped element is investigated and the formation of a shock-wave of a low-loss nonlinear transmission line with distributed diodes is studied. In the simulation results, the modeling of rapidly rising edges occurring in the time signal are demonstrated     

A new multi-valued neural network for the extraction of lumped models of analog circuits

A novel identification technique for lumped models of general distributed circuits (i.e. microwave transmission lines, monolithic integrated circuits and filters) is presented. The approach is based on a hybrid multi-valued neuron neural network with a modified layer and learning process, whose convergence allows the validation of the approximated lumped model. The modified layer is generated by symbolic analysis of the model under exam. The inputs of the neural network are geometrical parameters, while the outputs represent the estimation of the lumped circuit parameters.     

基于IPD工艺的高通滤波器芯片设计

设计采用了集成无源器件(Integrated Passive Device,IPD)工艺设计了一款集总式紧凑型椭圆函数高通滤波器。设计采用砷化镓GaAs作为衬底材料,基于寄生参数和等效电路模型对螺旋电感和MIM(金属-介质-金属)电容进行理论分析,并在三维电磁场仿真软件HFSS中进行建模与仿真。经过调试,该模型截止频率9.2 GHz,在9.8 GHz通带上插入损耗小于2 dB,在0~7.2 GHz阻带抑制>30 dB,尺寸仅为640μm×865μm×84μm,有效缩小了无源滤波器的尺寸,验证了基于GaAs IPD工艺的集总式高通滤波器设计的可行性。