Two-port Parameters Research Articles

Extraction of High-Frequency Phase-to-Phase Coupling in AC Machine Using Mixed-Mode Network Parameters

This paper proposes a method that extracts the phase-to-phase coupling of the three-phase stator winding of an ac motor for high-frequency characterization. Under the assumption of a symmetric structure, the multiport network parameters are obtained by the conversion of two-port mixed-mode network parameters. The proposed method simplifies the calculation to extract the impedance parameters of the three-phase winding structure without the full six-port measurement. Using the extracted parameters, we can construct a T-equivalent circuit and the corresponding transmission line model of a phase line, where the phase-to-phase coupling is distinguished from the self-coupling terms. Through the constructed equivalent circuit, the effect of the phase-to-phase coupling is clearly observed by comparing the high-frequency transmission line parameters. To verify the proposed method, the calculated input impedance is compared with the measured data.

Feedback Modeling Using Bilateral Two Ports

A technique is developed for representation of any arbitrary linear network as a feedback system. It is based on the fundamental feedback model introduced by Black for systems constituted by unilateral two-port networks. The application of the model is extended to circuits consisting of bilateral two-ports. The system's feedback loop gain for any of the four possible feedback configurations is expressed in terms of parameters of the constituent two-ports connected in cascade. An example is given to illustrate the benefits of the developed technique.

Device Simulation of Hydrogen-Terminated Diamond Mosfet and Extraction of Small-Signal Parameters

Diamond has exceptional properties suitable for electronic and photonic devices. In particular, hydrogen-terminated diamond (HTD) FET devices have been studied recently for potential radio-frequency (RF) applications by exploiting its high conductivity at diamond surface, high thermal conductivity and simple fabrication process [1-3]. However, the device simulation of such FET device is rarely reported because the surface conductive mechanism is not fully understood. In this work, a new device structure including a surface adsorbate layer (ADL) is presented and a possible explanation of the formation of surface conductive layer is provided. Based on our theory, the 2D device simulation is achieved using Sentaurus Technology Computer-Aided Design software; both the capacitance-voltage (C-V) and DC current-voltage (I-V) properties of the HTD MOSFET can be understood well. It is found that the current mainly flow at diamond surface when the drain-source voltage (VDS) is small but meander into the bulk when |VDS| becomes larger. The working mode of the device can change from enhancement to depletion as the gate length (Lg) shrinks, and the threshold voltage becomes very sensitive to Lg when Lg≤0.2μm. The off-state leakage current increases drastically when Lg is approaching 50nm, causing the on/off current ratio dropping from 106 to 103. In addition, the radio-frequency (RF) small-signal equivalent circuit of the device is generated and the frequency responses of the circuit components are studied. For devices with small gate length (<0.2μm), the non-quasi-static (NQS) effect happens at the frequency over 10GHz, making the HTD device suitable for applications in microwave range. The simulated transition frequency fT is around 170GHz when Lg=50nm, but it is greatly affected by the source/drain series resistance. Finally, a strategy is presented to extract the values of circuit components from simulated two-port parameters, which works well up to 2GHz. [1] M. Schwitters, M. P. Dixon, A. Tajani, D. J. Twitchen, J. I. S. E. Coe, H. El-Haji et al., Diamond-MESFETs-synthesis and integration, IEEE European Radar Conference, (2005) pp.1-4. [2] M. Kasu, K. Ueda, H. Ye, Y. Yamauchi, S. Sasaki, T. Makimoto, High RF output power for H-terminated diamond FETs, Diamond and Related Materials, 15(2006) pp.783-786. [3] J. L. Liu, C. M. Li, R. H. Zhu, J. C. Guo, L. X. Chen, J. J. Wei et al., RF characteristic of MESFET on H-terminated DC arc jet CVD diamond film, Applied Surface Science, 284 (2013) pp.798-803.

Model Reduction of Potential Transformer Based on Revised Minimum Information Loss Method

The circuit model of potential transformer (PT) is indispensable in accurately simulating the electromagnetic characteristic under the lightning overvoltage and very fast transient overvoltage in power systems. This paper utilizes a reduction algorithm for potential transformer based on revised minimum information loss method (RMIL). First, we measured a 10 kV single phase potential transformer using the Agilent 4395A network/spectrum/impedance analyzer. Second, we obtained the rational approximation of two-port circuit parameters by vector fitting (VF). At last, revised minimum information loss method is applied to reduction the state equation of circuit parameters. Comparisons between the reduced and original are given to illustrate the approximating performance of RMIL.

An Extraction of Two-Port Noise Parameters From Measured Noise Powers Using an Extended Six-Port Network

In this paper, we present a formulation for extracting the noise wave correlation matrix of a linear two-port device-under-test (DUT) from measured noise powers using a designed six-port network. The noise powers are measured using a conventional noise figure analyzer. The extracted noise wave correlation matrix can then be converted into conventional two-port noise parameters. The proposed measurement equipment is very simple and leads to a very low cost. The proposed method is experimentally verified through measurements of various DUT samples.

Two-Port Characteristic Analysis for Transformers with the Large Scale Windings Based on Sparse Matrix

In order to calculate the two-port wide frequency parameters of a large transformer quickly and accurately, parameter calculation of multi-conductor transmission lines model is proposed based on the sparse matrix operation. It solved the problem caused by the large matrix. Firstly, multi-conductor transmission lines model of the transformer windings is established. Secondly, matrix characteristics ofYandZis analyzed, based on which the block storage and computation method is applied. Then the frequency-domain model is solved based on sparse matrix operation. At last, taking a SS11-20000/110 transformer as an example, the correctness of this method has been verified by comparing calculation results with measurement results.

Siting and Sizing of DG in Medium Primary Radial Distribution System with Enhanced Voltage Stability

This paper intends to enumerate the impact of distributed generation (DG) on distribution system in terms of active as well as reactive power loss reduction and improved voltage stability. The novelty of the method proposed in this paper is the simple and effective way of sizing and siting of DG in a distribution system by using two-port Z-bus parameters. The validity of the method is verified by comparing the results with already published methods. Comparative study presented has shown that the proposed method leads existing methods in terms of its simplicity, undemanding calculation procedures, and less computational efforts and so does the time. The method is implemented on IEEE 69-bus test radial distribution system and results show significant reduction in distribution power losses with improved voltage profile of the system. Simulation is carried out in MATLAB environment for execution of the proposed algorithm.

Scaling of electromagnetic transducers for shunt damping and energy harvesting

Abstract In order for an electromagnetic transducer to operate well as either a mechanical shunt damper or as a vibration energy harvester, it must have good electromechanical coupling. A simple two-port analysis is used to derive a non-dimensional measure of electromechanical coupling, which must be large compared with unity for efficient operation in both of these applications. The two-port parameters for an inertial electromagnetic transducer are derived, from which this non-dimensional coupling parameter can be evaluated. The largest value that this parameter takes is approximately equal to the square of the magnetic flux density times the length of wire in the field, divided by the mechanical damping times the electrical resistance. This parameter is found to be only of the order of one for voice coil devices that weigh approximately 1 kg, and so such devices are generally not efficient, within the definition used here, in either of these applications. The non-dimensional coupling parameter is found to scale in approximate proportion to the device's characteristic length, however, and so although miniaturised devices are less efficient, greater efficiency can be obtained with large devices, such as those used to control civil engineering structures.

Analysis for Modeling Electromagnetic Characteristics of Via in High-Speed Printed Circuit Board

In this paper, firstly, full-wave electromagnetic simulation software is employed to analyze vertical via, influences of via radius, stub, pad and anti-pad radius on Signal Integrity (SI) are studied. And then, the equivalent circuit model for through via is established and the model RLC parameters are extracted based on the two-port network admittance parameter theory. On the basis of this, empirical model of via at high frequency and its model parameter extraction method is given. Finally, simulation and comparison verify the effectiveness of the equivalent circuit model. The results prove that the modeling method and parameter extraction are effective and practical for via electromagnetic characteristics analysis, and applicable to through via without stub when the frequency is less than 7.5GHz.

Two-port network analysis and modeling of a balanced armature receiver

Models for acoustic transducers, such as loudspeakers, mastoid bone-drivers, hearing-aid receivers, etc., are critical elements in many acoustic applications. Acoustic transducers employ two-port models to convert between acoustic and electromagnetic signals. This study analyzes a widely-used commercial hearing-aid receiver ED series, manufactured by Knowles Electronics, Inc. Electromagnetic transducer modeling must consider two key elements: a semi-inductor and a gyrator. The semi-inductor accounts for electromagnetic eddy-currents, the ‘skin effect’ of a conductor (Vanderkooy, 1989), while the gyrator (McMillan, 1946; Tellegen, 1948) accounts for the anti-reciprocity characteristic [Lenz's law (Hunt, 1954, p. 113)]. Aside from Hunt (1954), no publications we know of have included the gyrator element in their electromagnetic transducer models. The most prevalent method of transducer modeling evokes the mobility method, an ideal transformer instead of a gyrator followed by the dual of the mechanical circuit (Beranek, 1954). The mobility approach greatly complicates the analysis. The present study proposes a novel, simplified and rigorous receiver model. Hunt's two-port parameters, the electrical impedance Ze(s), acoustic impedance Za(s) and electro-acoustic transduction coefficient Ta(s), are calculated using ABCD and impedance matrix methods (Van Valkenburg, 1964). The results from electrical input impedance measurements Zin(s), which vary with given acoustical loads, are used in the calculation (Weece and Allen, 2010). The hearing-aid receiver transducer model is designed based on energy transformation flow [electric→ mechanic→ acoustic]. The model has been verified with electrical input impedance, diaphragm velocity in vacuo, and output pressure measurements.This receiver model is suitable for designing most electromagnetic transducers and it can ultimately improve the design of hearing-aid devices by providing a simplified yet accurate, physically motivated analysis.This article is part of a Special Issue entitled “MEMRO 2012”.

Analytical modeling of a sandwiched plate piezoelectric transformer-based acoustic-electric transmission channel

The linear propagation of electromagnetic and dilatational waves through a sandwiched plate piezoelectric transformer (SPPT)-based acoustic-electric transmission channel is modeled using the transfer matrix method with mixed-domain two-port ABCD parameters. This SPPT structure is of great interest because it has been explored in recent years as a mechanism for wireless transmission of electrical signals through solid metallic barriers using ultrasound. The model we present is developed to allow for accurate channel performance prediction while greatly reducing the computational complexity associated with 2- and 3-dimensional finite element analysis. As a result, the model primarily considers 1-dimensional wave propagation; however, approximate solutions for higher-dimensional phenomena (e.g., diffraction in the SPPT's metallic core layer) are also incorporated. The model is then assessed by comparing it to the measured wideband frequency response of a physical SPPT-based channel from our previous work. Very strong agreement between the modeled and measured data is observed, confirming the accuracy and utility of the presented model.

Maximum Achievable Efficiency in Near-Field Coupled Power-Transfer Systems

Wireless power transfer is commonly realized by means of near-field inductive coupling and is critical to many existing and emerging applications in biomedical engineering. This paper presents a closed form analytical solution for the optimum load that achieves the maximum possible power efficiency under arbitrary input impedance conditions based on the general two-port parameters of the network. The two-port approach allows one to predict the power transfer efficiency at any frequency, any type of coil geometry and through any type of media surrounding the coils. Moreover, the results are applicable to any form of passive power transfer such as provided by inductive or capacitive coupling. Our results generalize several well-known special cases. The formulation allows the design of an optimized wireless power transfer link through biological media using readily available EM simulation software. The proposed method effectively decouples the design of the inductive coupling two-port from the problem of loading and power amplifier design. Several case studies are provided for typical applications.

All possible second-order four-impedance two-stage Colpitts oscillators

The authors report all the possible four-impedance settings that yield a valid second-order two-stage Colpitts oscillator. These settings are obtained following an exhaustive search conducted on two possible structures of the oscillator modelled through two-port network transmission parameters. Only valid second-order cases with a maximum of three reactive elements are reported. Experimental and Spice verification of a selected example using both MOS and BJT transistors is given.

Partitioned-Time Transient Simulation via a Hybrid Time–Frequency Domain Methodology

This paper presents a hybrid time-frequency domain methodology to calculate midfrequency transients of an electrical network that includes transmission lines (TLs) and considering that the simulation is carried out on a partitioned-time basis. Basically, the line is modeled as a two-port element and the network simulation is performed in the frequency domain for each time subinterval. The transition between subintervals is made by calculating an equivalent current source for each end of the line. These sources represent the initial conditions for a subsequent subinterval, and their calculation is based on a rational approximation of the two-port line parameters. The conversion of frequency-domain variables to the time domain is efficiently performed through numerical Laplace transform operations. A sequential closure of a three-phase TL is presented for illustration of the proposed methodology.

Synthesis of Wideband Multicoupled Resonators Filters

A method for the synthesis of multicoupled resonators filters with frequency-dependent couplings is presented. A circuit model of the filter that accurately represents the frequency responses over a very wide frequency band is postulated. The two-port parameters of the filter based on the circuit model are obtained by circuit analysis. The values of the circuit elements are synthesized by equating the two-port parameters obtained from the circuit analysis and the filtering characteristic function. Solutions similar to the narrowband case (where all the couplings are assumed frequency independent) are obtained analytically when all coupling elements are either inductive or capacitive. The synthesis technique is generalized to include all types of coupling elements. Several examples of wideband filters are given to demonstrate the synthesis techniques.

Design of non-balanced cross-coupled oscillators with no matching requirements

Using two-port network transmission parameters we derive the general characteristic equation of a cross-coupled circuit topology which involves two active devices and four or six impedances. The derived equations are generic and apply both to BJT or MOS transistors and even any other active device without any matching constraints. Application to realising novel non-balanced non-matched cross-coupled oscillators is demonstrated. Spice simulations of a MOS oscillator in a 0.25 technology are given as well as experimental results from an oscillator employing discrete Bipolar transistors.

Transmission line characterization on silicon considering arbitrary distribution of the series and shunt pad parasitics

Abstract This paper presents an analytical method to simultaneously determine the complex characteristic impedance and the pad parasitics of transmission lines fabricated on silicon. The method uses experimental two-port network parameters of two lines differing in length without the need of a reflect standard such as that required in TRL-like formulations. Furthermore, the losses associated with the silicon substrate are accurately considered using the experimentally determined complex propagation constant of the lines and three different configurations for the pad parasitics can be assumed. When using the extracted parameters in a model to represent transmission lines, excellent agreement between simulated and experimental data was achieved up to 50 GHz even for lines with lengths different to those used in the determination process.

Synthesis of wideband matching devices using harmonic-mean power conversion coefficient

Analytically strict expressions for calculation of the parameters of elementary two-ports in the (L, C) element basis are obtained in the case of wideband matching of arbitrary immittances of the signal source and the load whose information is used without an approximation error. The efficiency of application of the harmonic-meanpower conversion coefficient in the matching objective functions is demonstrated. Algorithms for optimization of parameters of a matching device comprised of elementary twoports that use the cascade synthesis and the method of reference sections are proposed. Examples of calculation are given.

Improved GMI Sensors Using Strongly-Coupled Thin Pick-Up Coils

The performance of Giant Magneto-Impedance (GMI)-based magnetometers is currently limited by electronics, particularly as regards the equivalent magnetic noise. Thus, it is crucial to increase the sensitivity before demodulation. With that objective, we analyze one solution, using a wire-wound device, consisting of a very thin pick-up coil wrapped around a GMI wire, as a sensing element. We present an electrical sensor model using classical two-port network impedance parameters. It allows us to predict the expected improvement in sensitivity, simulating the device implementation in an appropriate electronic design. Preliminary results suggest an improvement in sensitivity by a factor 2 for a 0 dBm sinusoidal excitation voltage source at 10 MHz. Noise measurements support this analysis and show an intrinsic output magnetic noise improvement in the same ratio.

Characterization of Electrical Transitions Using Transmission Line Measurements

An analytical methodology for characterizing electrical transitions associated with transmission line-based microwave channels is presented in this paper. The methodology is formulated using <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ABCD</i> matrixes obtained from <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i> -parameters measured to two lines with different length and terminated with the transition under investigation. This allows to determine the two-port network parameters of the transition in a simple and direct way. Excellent results are obtained when characterizing coplanar waveguide-to-microstrip and coaxial-to-microstrip transitions. Moreover, the methodology was also successfully applied to obtain the network parameters of packages fabricated on printed circuit board technology.