Equivalent Circuit Extraction Research Articles

Full-wave modeling and automatic equivalent-circuit generation of millimeter-wave planar and multilayer structures

A general method for the automated extraction of lumped-element equivalent circuits for linear passive reciprocal distributed microwave circuits from time-domain scattering signals is presented. The proposed method autonomously generates network topology as well as parameter values while preserving circuit properties like reciprocity and passivity. Modeling examples for a two- and three-port structure are given.

Accurate modeling and parameter extraction for MOS transistors valid up to 10 GHz

Accurate modeling and efficient parameter extraction of the small signal equivalent circuit of submicrometer MOS transistors for high-frequency operation are presented. The equivalent circuit is based on a quasi-static approximation which was found to be adequate in the gigahertz range if the extrinsic components are properly modeled. It includes the complete intrinsic quasi-static MOS model, the series resistances of gate, source, and drain, and a substrate coupling network. Direct extraction is performed by Y-parameter analysis on the equivalent circuit in the linear and saturation regions of operation. The extracted results are physically meaningful and can be used to de-embed the extrinsic effects such as the substrate coupling within the device. Good agreement has been obtained between the simulation results of the equivalent circuit and measured data up to 10 GHz.

Element extraction of GaAs dual-gate MESFET small-signal equivalent circuit

A procedure for the extraction of intrinsic and extrinsic elements of dual-gate MESFET (DGMESFET) small-signal equivalent circuit is described in this paper. All the elements to be used as the initial values for the optimization calculation are extracted from dc and RF measurements with analytical formula. The elements of extrinsic series resistance are determined by considering the distributed channel resistance under the regions of two gates with the use of the end resistance measurement method. The elements of extrinsic capacitance and inductance are extracted by three-port Y-matrix and Z-matrix calculation from cold measurements. The intrinsic elements of DGMESFET, which is biased properly to be two decoupled single-gate MESFET's, are directly extracted from hot measurements. The extracted element values are then optimized to fit the resulting equivalent circuit to the measured three-port S-matrix. The developed procedure gives a practical and accurate approach for DGMESFET characterization.

Extraction of equivalent circuits for microstrip components and discontinuities using the genetic algorithm

This letter introduces a new technique based on the application of the genetic algorithm (GA) for extracting the equivalent circuits-from measured or computed S-parameters-that can be inserted into SPICE simulations. The GA is a robust optimization tool that is shown to yield excellent results for discontinuities in microstrip lines, for instance a right-angled bend, and for microwave circuits, e.g., planar inductors and parallel plate capacitors.

Methods of using commercial electromagnetic simulators for microwave and millimeter-wave circuit design and optimization

Efficient utilization of commercial electromagnetic (EM) simulators for design and optimization of microwave (MW) and millimeter-wave (MMW) circuits is achieved by classifying design problems into three categories-characterization of circuit elements, optimization of circuit elements, and creation of circuit element libraries such as scalable libraries. Practical aspects of the methods are illustrated by several examples. An equivalent circuit extraction technique suitable for n-port coupled structures is provided. The derived equivalent circuit is useful for extrapolating data, optimization, and deriving scalable models.

Circuits and simulations at 1THz

The current state-of-the-art in device and circuit simulation, design and application for semiconductor devices operating in the terahertz regime is reviewed. The evolution of physical models to describe and investigate tunnelling and other ultra-small device structures is described. Simulations based on quantum hydrodynamic models and self-consistent solutions of the Poisson and Schrodinger equations, using analytical and numerical techniques are considered. Equivalent circuit extraction methods are considered, together with device models up to 2 THz. Examples of results obtained from simulations of terahertz devices are given, including resonant tunnelling structures. The design and modelling of circuits incorporating semiconductor tunnelling devices is discussed and illustrated with examples of recent developments. The challenges facing circuit designers and the potential applications for this technology are highlighted.

A new approach for the extraction of an FET equivalent circuit from measured S parameters

A new method for the extraction of the 13-element GaAs FET model from hot S parameters is presented. The method reduces the uniqueness problem that exists between the parasitic gate resistance Rg and the channel resistance Ri. Thirteen error functions are used, with the order of optimization determined through a principle-components sensitivity analysis. © 1996 John Wiley & Sons, Inc.

Characterization of off-slot discontinuity in unilateral fin line

A new type of fin line discontinuity, which consists of a rectangular conducting strip placed transversely on the back side of the air dielectric interface containing the slot, is characterized in this work. Modeling of the fin line cavity containing the discontinuity is carried out using hybrid mode analysis, and then the transverse resonance technique is used to extract equivalent circuit parameters of the discontinuity. Suitable sets of basis functions are chosen for accurately representing the field in the slot and the current on the strip. Calculated results are compared with the measured results for a sample discontinuity to validate the choice of the basis functions.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Direct extraction of equivalent circuit parameters for heterojunction bipolar transistors

A new method is presented for the direct extraction of hybrid-T equivalent circuits for heterojunction bipolar transistors. The method differs from previous ones by extracting the equivalent circuit without using test structures or numerical optimization techniques. Instead, all equivalent circuit parameters are calculated analytically from small-signal S-parameters measured under different bias conditions. The analysis includes the distributed nature of the HBT base. The calculated parameters are essentially frequency-independent and they exhibit systematic bias dependence over the typical operating range of the transistor. Thus, the present method ensures unique and physically meaningful parameters for transistor design improvement and large-signal circuit simulation. In addition, the present method is much faster than the numerical optimization method. >

Recess dependent breakdown behavior of GaAs-HFETs

GaAs based HEMT devices were fabricated with a constant recess towards the source, whereas the recess width towards the drain was varied. While the off-state breakdown voltage has been improved by the use of a wide recess towards the drain, no dependence of the on-state breakdown on the recess configuration was observed. The constant breakdown voltage in the on-state is analysed by the feedback parameters obtained from an extraction of the small signal equivalent circuit. Although the extrinsic gate drain capacitance could be reduced by the use of a wider recess configuration, it is assumed that the intrinsic drift region is independent of the recess configuration.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A general purpose Maxwell solver for the extraction of equivalent circuits of electronic package components for circuit simulation

The electromagnetic modeling of electronic packages is discussed, and a general-purpose Maxwell solver is presented for deriving equivalent circuits of various components of a package that can be inserted in a SPICE-type circuit simulation program to investigate the electrical performance of the package. The solver is based on the finite-difference-time-domain (FDTD) algorithm. Its usefulness is illustrated by applying it to a number of representative problems.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>