HF Characterization and Nonlinear Modeling of a Gapped Toroidal Magnetic Structure

The frequency dependent characteristics of a gapped toroidal structure are extracted empirically over a bandwidth that exceeds 30MHz. The analysis is complicated due to nonlinear flux distributions, magnetic properties of the core material, leakage inductance, stray capacitances, and eddy currents in the windings. A permeance model of the core is implemented to model the magnetic circuit. The model includes a linear lumped element equivalent circuit to approximate the nonlinear complex permeability of the core, which was measured empirically. Stray capacitance and inductance of the winding are also modeled. A gyrator is used to couple the electric and magnetic models for circuit simulation. The measured and simulated results of open-circuit impedance from the secondary winding and the transimpedance gain (V/A) of the current sensor are compared and discussed.     

System identification and modelling based on a double modified multi-valued neural network

A novel identification technique for the extraction of lumped circuit models of general distributed or stray devices is presented. The approach is based on two multi-valued neuron neural networks used in a joined architecture able to extract hidden parameters. The convergence allows the validation of the approximated lumped model and the extraction of the correct values. The inputs of the neural network are the geometrical parameters of a given structure, while the outputs represent the estimation of the lumped circuit parameters. The method uses a frequency response analysis approach in order to elaborate the data to present to the net.     

A lumped winding model for use in transformer models for circuitsimulation

A lumped circuit model is derived for a winding in a multiwinding transformer. The model is intended to be used in transformer models for circuit simulation using electrical-network simulators. A hybrid (partly electrical, partly magnetic) modeling approach is adopted in which magnetic components are described using the capacitance-permeance analogy instead of the widespread resistance-reluctance analogy. The network correctly models energy storage and power dissipation due to DC series wire resistance and to eddy current losses, independent of the way of excitation of the winding (electrical and/or magnetic). All component values are frequency independent and are parameterized by geometrical parameters, winding data and material parameters. The mathematical continued-fraction approximation technique is applied to derive approximating circuits to model eddy current losses. A fourth-order circuit shows acceptably small errors up to a frequency of about a factor of 1500 above the frequency at which eddy-current losses become apparent. The model is applied in a six-layer two-winding transformer model. Calculations both in the frequency domain and in the time domain show good agreement with measurements     

An efficient systematic approach to model extraction for passivemicrowave circuits

This paper introduces a new systematic approach to equivalent circuit model extraction for linear microwave passive circuits directly from full-wave frequency domain simulation. The devices being modeled may be either lossless or lossy. Adaptive frequency sampling is used to minimize the computational effort of EM simulation while critically assisting in determining the pole locations of an RF circuit. A simple circuit model for lossy RF circuits along with a determined starting point of optimization of lumped element component values is also presented in detail. The overall result is an efficient and accurate means to produce a complete equivalent lumped element model for RF circuits that is suitable for use in conventional SPICE-like simulation software     

A capacitance model for GaAs MESFETs

A capacitance model for a GaAs MESFET suitable for implementation in the circuit analysis program SPICE is presented. The model consists of nonlinear capacitances that are a function of two voltages. Such a model gives rise to ordinary nonlinear capacitances and transcapacitances. The placement of these elements in the Y matrix is shown. The empirical equations for the gate charge of a GaAs MESFET given provide an accurate SPICE model for the gate charge and capacitances of a MESFET. A comparison of measured capacitance values with the modeled values gives close enough agreement for circuit simulation purposes     

A study on stray capacitance modeling of inductors by using thefinite element method

Stray capacitance modeling of an inductor is essential for its RF equivalent circuit modeling and inductor design. Stray capacitance determines an inductor's performance and upper frequency limit. A method has been proposed for modeling the distributed stray capacitance of inductors by the finite element method and a node-to-node lumped capacitance network. The effects of wire insulation layer, ferrite core, number of segments used to model the circumference of a wire cross section, pitch and coil-to-core distances, and the capacitance between nonadjacent turns, etc., an an inductors' self-capacitance and calculation accuracy, have all been considered. The calculated equivalent lumped stray capacitance for a rod inductor with a ferrite core is compared to that estimated from measurement. Good agreement between them has been observed     

General stray-insensitive first-order active SC network

A general first-order switched-capacitor network using one operational amplifier, insensitive to stray capacitances, is proposed. Its application to realise an inverting bilinear lossy integrator and a circuit for realising finite zeros is discussed.     

Analysis, design, and optimization of spiral inductors andtransformers for Si RF ICs

Silicon integrated circuit spiral inductors and transformers are analyzed using electromagnetic analysis. With appropriate approximations, the calculations are reduced to electrostatic and magnetostatic calculations. The important effects of substrate loss are included in the analysis. Classic circuit analysis and network analysis techniques are used to derive two-port parameters from the circuits. From two-port measurements, low-order, frequency-independent lumped circuits are used to model the physical behavior over a broad-frequency range. The analysis is applied to traditional square and polygon inductors and transformer structures as well as to multilayer metal structures and coupled inductors. A custom computer-aided-design tool called ASITIC is described, which is used for the analysis, design, and optimization of these structures. Measurements taken over a frequency range from 100 MHz to 5 GHz show good agreement with theory     

Double-layer microstrip structures—lumped capacitances and open-circuit end correction

The analysis is reported of the lumped capacitance and open-circuit end effects of finite-length strip conductors in double-layer microstrip structures. Two specific configurations, namely double-layer microstrip and microstrip-with-overlay configurations, are considered. The analytical approach uses the variational technique in the Fourier transform domain in conjunction with the transverse transmission line technique. It is identified that the only parameter needed to analyse the lumped capacitances and open-circuit end effects of these microstrip structures is the admittance at the charge plane. This parameter can easily be determined from the two-wire transmission line equivalent circuit. Extensive numerical data are generated for the lumped capacitances and open-circuit end effects of the finite-length strip conductor in double-layer microstrip and microstrip-with-overlay configurations. The data presented should be useful in designing lumped elements and filters in these configurations.     

毫米波频段宽带CMOS片上巴伦的分析与建模

详细讨论了基于CMOS工艺宽带片上巴伦的实现.首先分析了应当采用的结构及参数化版图.然后给出了一个宽带集总元件等效电路模型,该模型考虑了各种必须考虑的物理效应.通过采用物理公式与优化拟合相结合的方法提取了模型参数,以保证模型在很宽频带范围内具有较高精度.最后,采用台湾半导体制造有限公司(TSMC)提供的0.13μm混合信号/射频CMOS工艺实际制作了两个具有不同几何参数的巴伦,并使用Agilent E8363B矢量网络分析仪测量了S参数.测量结果表明在高达毫米波频段范围内,模型仿真结果与测试结果符合得很好.     

太赫兹平面肖特基二极管参数模型

根据太赫兹平面肖特基二极管物理结构,在理想二极管SPICE参数模型的基础上建立了二极管小信号等效电路模型。依据该二极管等效电路模型设计了基于共面波导（CPW）去嵌方法的二极管S参数在片测试结构,并对其在0.1~50 GHz、75~110 GHz频率范围内进行了高频小信号测试,利用测试结果提取了高频下二极管电路模型中各部分电容、电阻以及电感参数。将相应的高频下电容与电阻参数分别与低频经验公式电容值和直流I-V测试提取的电阻值进行了对比,并利用仿真手段对高频参数模型进行了验证。完整的参数模型以及测试手段相较于理想二极管SPICE模型和传统的参数提取方法可以更为准确地表征器件在高频下的工作状态。该建模思路可用于太赫兹频段非线性电路的优化设计。     

Analysis and Modeling of Energy Consumption in RLC Tree Circuits

In this paper, the energy consumption of resistance-inductance-capacitance (RLC) trees is analytically modeled. In particular, the results obtained by the same authors for RC tree circuits are generalized, allowing for a deep understanding of the impact of the inductance. The modeling approach proposed relies on the adoption of an equivalent second-order RLC circuit, whose energy consumption is evaluated in a closed form. These results are then extended to RLC circuits with arbitrary order, deriving a simple and accurate model. The energy dependence on the input rise time is also analyzed in detail, identifying the ranges for which the RLC circuit can be approximated to a simple capacitance or an RC circuit. The model equations provide an insight into the dependence of the energy consumption on the circuit parameters. Indeed, the energy is explicitly expressed as a function of the resistances, capacitances and inductances of the original network. The energy model proposed is shown to be accurate enough for modeling purposes through comparison with SPICE simulations, as the error is typically in the order of a few percentage points.     

Microwave Filters of Coupled Lines and Lumped Capacitances (Correspondence)

Two frequency transformations are given which enable microwave filters to be realized with coupled lines and lumped capacitances from a characteristic prototype lumped network to a good approximation. The procedore includes filters originally proposed by Matthaei and CristaI, and enables realizations for large bandwidths. A number of examples demonstrate the efficiency of the procedures.     

A simple subcircuit extension of the BSIM3v3 model for CMOS RFdesign

An accurate and simple lumped-element extension of the BSIM3v3 MOSFET model for small-signal radio-frequency circuit simulation is proposed and investigated. Detailed comparisons of the small-signal y and s parameters with both two-dimensional device simulations and measurement data are presented. A procedure is developed to extract the values of two lumped resistors-the only added elements. The non-quasi-static and substrate effects can be modeled with these two resistors to significantly improve the model accuracy up to a frequency of 10 GHz, which is about 70% of the f_T of the 0.5 μm NMOS transistor     

Design of transformerless quasi-broad-band matching networks forlumped complex loads using nonuniform transmission lines

A simple design method for transformerless and lossless quasi-broadband matching of a lumped RC load is presented by use of a parabolic nonuniform transmission line. The key idea in removing an ideal transformer from the matching network is based on impedance transformation of the nonuniform transmission line, whose mixed lumped and distributed equivalent circuit contains an ideal transformer. Illustrative examples and some design curves are presented     

Comparative study of stack interwinding micro-transformers on silicon monolithic

Interwinding planar micro-transformers are developed using micro-machining technique. The transformers with a vertically stack coil structure on silicon monolithic substrate are designed to achieve high coupling and high inductance value in a relatively small coil area. In this work, various types of stack interwinding transformer are fabricated, measured and compared. The results show that the metal-to-metal effect of a multi-layer structure contributes to the significant increase of parasitic capacitances and hence limits the operating frequency. Moreover, the lumped element parameters are analyzed by extracting the measured S-parameter. This investigation can give important information for the future development of three-dimensional RF devices.     

A High-Resolution Capacitance-to-Frequency Converter

This paper describes an integrated sampled-data sinusoidal oscillator with AGC amplitude stabilization, the frequency of which is proportional to an external low value capacitor (2-20 pF). The circuit, based on a switched-capacitor two-integrator loop, is insensitive to stray capacitances between sensing nodes and ground and features high resolution (16 bits) and excellent linearity (better than 0.1 percent) as well as very low power consumption (less than 0.1 mW). Such a "capacitance-to-frequency converter" is particularly suitable for interfacing variable-capacitance sensors (pressure transducers, accelerometers,... ) in applications requiring high accuracy but where signal bandwidth is limited to a few hundred hertz.     

Large-signal computer simulations of the contact, circuit, and bias dependence of X-band transferred electron oscillators

We present a treatment synthesizing the roles of the contact and the circuit forX-band length transferred electron devices sustaining self-excited oscillations. The contact is modeled with specific cathode electric-field relations. The circuit is modeled with lumped elements. The scope of the simulation is relevant to both high-efficiency InP oscillations and the moderate-efficiency GaAs oscillations.     

射频放电激励激光器阻抗特性实验研究

利用自行研制的传感器＾「１」,通过对射频放电电压电源以及其相位角的精确测定,结合放电管的等效电路,对内置电极射频气体放电激励激光阻抗特性进行研究,得出内置电极射频气体放电激励激光器等离子体的伏安特性曲线,以及等离子体电阻和气体压强、气体放电电流之间的关系。     

单端正激变换器谐振磁复位技术的研究

针对单端正激式DC／DC变换器的磁复位问题,本文对无需外加辅助电路,仅通过开关器件寄生电容与变压器励磁电感实现的谐振式磁复位电路进行了研究。文中详细分析了电路在一个开关周期内的6种不同开关模态．给出了参数设计的计算公式,进行了仿真分析和实验研究,并应用于车载式锂离子动力电池充电单元的研制。