Two-port Parameters Research Articles

STUDY OF THE REGULARITY CONDITIONS AT SERIAL CONNECTION OF TWO-PORTS

The possibility of preserving the regularity condition for composite two-ports formed by serial connection of the original ones is studied. Numerous textbooks, reference books, collections of problems on the theoretical foundations of electrical engineering provide a rule for determining generalized parameters at the series connection of two-ports by adding the matrices of coefficients Z' and Z'' of the original ones. These sources note that this rule is true only in cases when the regularity condition is met, i.e. pairwise equality of currents at the input and output of each of the two-ports is maintained in any mode of operation of the electrical circuit. When two-ports are connected in series, a new electrical circuit is obtained in which maintaining pairwise equality of currents in two pairs of selected branches can only be a private mode. That is why, it is doubtful that when connecting two-ports in series, the application of the known rule will take place. All possible options for the serial connection of two different two-ports presented by an equivalent T-shaped circuit are considered. To solve the problem, the loop current method is used and a condition is determined under which the pairwise equality of currents at the input and output of each of the two-ports in the load mode is maintained. As a result, it turns out that when connecting two-ports in series, the condition of regularity of the connection is not satisfied. In two of considered cases, the two-ports are converted, and in the third case, the composite two-port is converted into one pass-through two-port. This statement is also confirmed by determining the Z parameters of a composite two-ports by adding the matrices of coefficients Z' and Z'' of the original ones, which is satisfied only in the third of the considered variants.

Assessing the impact of step gate oxide and gate electrode engineering on performance of β-Ga2O3 MOSFET for high frequency applications

In the present work, the advantages of step gate oxide and gate electrode engineering designs have been amalgamated with scaled β – Ga2O3 MOSFET for ultra-high frequency applications. Various device attributes such as channel potential, electric field distribution, output and transfer characteristics etc., have been studied using both analytical modeling and simulation approaches. Furthermore, the paper also explores numerous high frequency figure of merits such as cut-off frequency, gain bandwidth product and transconductance frequency product etc. Two-port parameters i.e., scattering parameters, Rollett's stability factor etc., and high-power metrics such as output power and power-added-efficiency etc., have also been investigated. The variation of device gain with frequency has also been studied. Furthermore, a thorough comparison is drawn between the proposed device, the device with only step gate oxide engineering and a uniform gate throughout, and the conventional device without any of these designs for fair assessment. It has been demonstrated that the proposed design is reliable and efficient with significant improvement in abovementioned figure of merits which makes it suitable contender for ultra-high frequency applications.

High-Speed and High-Power Ge-on-Si Photodetector with Bilateral Mode-Evolution-Based Coupler

We propose a germanium-on-silicon photodetector with a bilateral mode-evolution-based coupler. Based on the double-sided mode-evolution, the light illuminates the whole Ge absorption region uniformly, which alleviates the space-charge effects and decreases the saturation effects. The simulated results show 53% more photocurrent generation and more than 19 times the opto-electrical bandwidth than conventional butt-coupled photodetectors under high-power illumination. In addition, an equivalent circuit model is presented to investigate the limiting factors of bandwidth. A genetic algorithm is used to extract the parameter values of components in an equivalent circuit by fitting the simulated two-port S22 parameter. The results show significant improvement in high-power and high-speed performance compared with conventional butt-coupled detectors.

Modeling Microwave Connectors Used as Signal Launchers for Microstrip Lines of Different Widths

A full characterization and modeling methodology for the electrical transitions introduced by coaxial connectors serving as interfaces for accessing microstrip (MS) lines is presented and verified up to 40 GHz. The associated two-port network parameters are obtained from measurements performed on MS lines of different lengths. Subsequently, two circuit models for the transition are proposed and used to assess the performance of the connector transition as the lines vary in width.

Equivalent Circuit Approximation to the Connector-Line Transition at High Frequencies using Two Microstrip Lines and Data Fitting

This article presents a method of obtaining an equivalent lumped element circuit to model the electrical connector-line transitions in the ultra-high frequency (UHF) band. First, the scattering matrices of two microstrip transmission lines that are otherwise identical but have the physical lengths of dd and 2d2⁢d are measured. Next, the theoretical model of the lines cascaded with the connector-line transitions modeled as lumped element circuits is established. The selection of the line lengths to be dd and 2d2⁢d results in an over determined system of equations that links the circuit component values to the two-port network parameters of the cascaded system. Finally, the least-squares data fitting procedure yields the best-fit component values. The results show that in our tested scenario, 3-component reactive circuit models well the transitions. Compared with the previous methods, the proposed approach does not require knowledge of the dielectric properties of the substrate of the measured transmission lines. This property integrates the method with our previous work on estimating a microstrip line substrate’s relative permittivity and loss tangent. The obtained transition circuit model is also validated through the testing of two quarter-wave transformers. The lines and transformers are implemented on a textile substrate to highlight the method’s applicability to wearable textile-based electronics.

Canonical Hyperchaotic Oscillators With Single Generalized Transistor and Generative Two-Terminal Elements

This paper describes systematic design process toward third-order autonomous deterministic hyperchaotic oscillators with two coupled generative two-terminal elements. These active devices represent alternative to conventional dissipative accumulation elements such as capacitors and inductors. Analyzed network structures contain generalized bipolar transistor as only active element. Three different networks are studied, depending on common-electrode configurations. In each case, transistor is modelled using two-port admittance parameters with the non-zero linear backward and polynomial forward trans-conductance. As proved in paper, scalar nonlinearity caused by amplification property of transistor can push circuit into chaotic and, more interestingly, hyperchaotic steady states. Existence of parameter spaces leading to robust chaotic and hyperchaotic solution is documented by using concept of one-dimensional Lyapunov exponents and colored high-resolution surface-contour plots of two largest numbers. Geometrical structural stability of generated strange attractors is proved via construction of the flow-equivalent chaotic oscillator and real measurement. Plane projections of interesting observed attractors are captured by oscilloscope.

Evidence of Strange Attractors in Class C Amplifier with Single Bipolar Transistor: Polynomial and Piecewise-Linear Case.

This paper presents and briefly discusses recent observations of dynamics associated with isolated generalized bipolar transistor cells. A mathematical model of this simple system is considered on the highest level of abstraction such that it comprises many different network topologies. The key property of the analyzed structure is its bias point since the transistor is modeled via two-port admittance parameters. A necessary but not sufficient condition for the evolution of autonomous complex behavior is the nonlinear bilateral nature of the transistor with arbitrary reason that causes this effect. It is proved both by numerical analysis and experimental measurement that chaotic motion is miscellaneous, robust, and it is neither numerical artifact nor long transient motion.

Antenna Analytical Representation by a Two-Port Network

System analysis is a powerful tool for researching modern wireless systems. This includes breaking such systems into parts that make them up and studying how these parts work together. All these parts can be represented as “black boxes” in the form of two-port or multiport networks with the common system of parameters. Antenna is an integral part of any wireless system, so it should be also represented as a two-port network. In this paper, an analytical model of an arbitrary single antenna in the form of a two-port network, whose electrical and noise parameters are described in terms of scattering matrices, is obtained. The initial data for creating the model are the antenna fundamental parameters, viz., the input reflection coefficient and the radiation efficiency. Applications of this model for antenna analysis operating in the transmitting, receiving, and scattering modes are demonstrated. A numerical example using the antenna scattering matrix for computer simulation of a wireless connection is given.

Load optimization factors for analyzing the efficiency of wireless power transfer systems using two-port network parameters

Load optimization factors for analyzing the efficiency of wireless power transfer systems using two-port network parameters

Energy harvesting using piezoelectric transducers for suspension systems

Energy harvesting by using functional materials in suspension systems bear potential to win-back certain (even if low) amounts of vibrational energy, otherwise dissipated via the conventional (passive) dampers. Piezoelectric (PE) ceramics are functional materials that can be used for transforming mechanical energy into electrical and vice versa. In this paper, we study the capabilities and efficiency of energy harvesting (EH) with PE transducers under two different kinds of external excitation: i) Periodic and ii) stochastic. An appropriate nonlinear lumped parameter electromechanical model (LPEM) is brought into the two-port network notation. Laboratory experiments were conducted under periodic external force-controlled excitation performed on a universal test machine (UTM). The two-port model parameters were identified and the model was validated by comparing results of numerical simulations and experiments. Extended simulations have been conducted to investigate the EH capabilities of PE transducers in automotive applications, i.e. EH in suspension systems under the standardized road conditions. The analysis results of the power conversion and EH efficiency are presented and discussed.

A unified method to extract the effective mobility in InGaAs metal-insulator-semiconductor field-effect-transistors using scattering-parameters

In this letter, we propose a unified method to extract the effective mobility (μeff) of In0.52Al0.48As/In0.7Ga0.3As/In0.52Al0.48As single-quantum-well (SQW) metal-insulator-semiconductor field-effect-transistors (MISFETs). The proposed method relies only on the measured high-frequency scattering-parameters (S-parameters) of the MISFETs in the linear regime. Two key metrics of MOS devices, intrinsic output conductance (go_i) and intrinsic gate capacitance (Cg_i), were extracted directly from the measured S-parameters using two-port network parameter theories, allowing us to compute the effective mobility of the MOS devices. Since the method only requires the small-signal S-parameter measurement data, it would be applicable to any kind of FETs and could be fruitful for studying the dependence of the effective mobility on lateral electric field intensity.

A New Two-Port Network Model-Based Pilot Protection for AC Transmission Lines

Conventional pilot protections used for EHV/UHV ac transmission lines require data synchronization between the two terminals of transmission line, and their performances are affected by the line capacitive charging current and load conditions. To tackle these problems, this paper proposes a new pilot protection scheme based on two-port network model of ac transmission lines. The new protection scheme calculates the two-port network parameters from the online measurements via the sequence components method, and then compares the solved parameters with their setting values to distinguish the internal and external faults. It does not require the data synchronization between two terminals of the transmission line. Moreover, its performance is not affected by the line capacitive charging current and load conditions. The applicability of the proposed scheme for series compensated lines is also analyzed. Effectiveness and accuracy of the proposed protection scheme have been verified by simulation tests.

A Low-Cost Compact Planar Dual-Band 3 dB Branch Line Coupler Using an Unbalanced CRLH

In this work, a compact dual-band 3 dB branch line coupler (BLC) is designed with center frequency at 2.45 GHz and 5.08 GHz using an unbalanced composite right/left-handed transmission line. Based on the two-port ABCD parameters, the lumped equivalent circuit of the proposed TL is extracted and optimized to obtain characteristic impedance at 2.45 GHz and 5.08 GHz. The right- and left-handed characteristics of the proposed TL are examined. Incorporating the proposed TL, a dual-band BLC with 0.29λg × 0.3λg size is obtained. The frequency response has magnitude imbalance of 0.8 dB, phase imbalance of 1.8° and 160 MHz bandwidth at 2.45 GHz and magnitude imbalance of 0.81 dB, phase imbalance of 0.006° and 100 MHz bandwidth at 5.08 GHz.

On the Accurate Voltage and Current Analytical Relationship to <inline-formula> <tex-math notation="LaTeX">${X}$ </tex-math> </inline-formula>-Parameters of a Nonlinear Two-Port Network

This paper introduces new analytical expressions that relate between voltage and current of a nonlinear two-port network. These formulas are defined and derived, analytically, from ${X}$ -parameters. They are also extension of the well-known linear two-port network parameters. These formulations are defined as follows. Linearized impedance parameters ( ${Z}$ -parameters) relate harmonic voltage components to harmonic current components at both network ports. Linearized admittance parameters are the inverse of linearized ${Z}$ -parameters and relate harmonic current components to harmonic voltage components. Linearized cascade parameters and linearized scattering transfer parameters relate entities at the input to that ones at the output of the network. Linearized hybrid parameters and linearized inverse hybrid parameters are defined in terms of a mixture of port variables. The proposed approach has been evaluated, and very good agreement has been obtained.

Diagonal Mode van der Pauw Stress Sensors: Proof of Diagonal-Mode Conjecture

The conjecture discussed in our previous paper [Jaeger, R. C., Motalab, M., Hussain, S., and Suhling, J. C., 2014, “Four-Wire Bridge Measurements of Silicon van der Pauw Stress Sensors,” ASME J. Electron. Packag., 136(4), p. 041014; Jaeger, R. C., Motalab, M., Hussain, S., and Suhling, J. C., 2018, Erratum: “Four-Wire Bridge Measurements of Silicon van der Pauw Stress Sensors,” ASME J. Electron. Packag., 140(1), p. 017001] was backed up by measurements and simulation results, but not mathematically proven. A proof based upon two-port impedance parameter reciprocity is presented with additional experimental confirmation.

Efficient Perturbation Method for Computing Two-Port Parameter Changes Due to Foreign Objects for WPT Systems

The change in the two-port parameters of a wireless power transfer (WPT) chain is evaluated when an object (foreign object) with given material parameters is placed in the vicinity of the WPT transmitter and receiver. An integral formula for the change of the two-port parameters due to the presence of a foreign object has been derived by using the generalized theory of reciprocity. It is emphasized that—instead of taking the differences of the two-port parameters calculated with and without the presence of the foreign object—the presented method provides the change of the two-port parameters directly from the calculated electromagnetic field at the location of the foreign object. As a result, the relatively small parameter changes can be predicted with good accuracy. Based on the application of the Born approximation, the possibility of computing an approximation of the changes of the two-port parameters is explored.

Computation of Two-Port Parameters in Magnonic Devices Through Circuit-Field Coupling

This paper presents a model for the computation of two-port parameters from the configuration of a typical Magnonic device involving two coplanar waveguides. A Permalloy thin film is saturated using an appropriate dc field. The first waveguide then performs the function of excitation of spin waves by superposition of an RF field. The second waveguide detects the excited wave vector in Damon–Eshbach mode at resonance frequency. The model is solved using the generalized mean residual method for a linearized approximation of the Landau–Lifshitz–Gilbert equation coupled with Maxwell equations. Complex impedance matrices from the two-port network are extracted for both uniformly saturated and non-uniform initial ground states. Findings report low absorption potential and shift in resonance frequency for highly non-uniform ground states. Validation of the model for uniformly saturated ground states is performed against experimental and semi-analytical findings, showing good agreement.

A New Interpretation of Through-Line Deembedding

Deembedding a device mounted between a pair of identical transitions requires the transition two-port parameters. These can be obtained using the through-line (TL) deembedding method requiring only through and uniform line deembedding standards. Other related deembedding methods introduce factors to scale a pair of eigenvectors to obtain the transition two-port parameters. In this paper, it is shown that these scaling factors are interdependent and provide a corrective reference plane adjustment. Moreover, the transition wave-transmission matrix can be factored into two wave-transmission matrices with one encapsulating the transition discontinuity and the other of a matched line to provide a corrective reference plane shift. This factorization permits incorporation of desired and corrective reference plane shifts, using data from a second matched line standard. With an emphasis on substrate-integrated waveguide, the proposed TL deembedding method is verified.

Middle-ear function in the chinchilla: Circuit models and comparison with other mammalian species

The middle ear efficiently transmits sound from the ear canal into the inner ear through a broad range of frequencies. Thus, understanding middle-ear transmission characteristics is essential in the study of hearing mechanics. Two models of the chinchilla middle ear are presented. In the first model, the middle ear is modeled as a lumped parameter system with elements that represent the ossicular chain and the middle-ear cavity. Parameters of this model are fit using available experimental data of two-port transmission matrix parameters. In an effort to improve agreement between model simulations and the phase of published experimental measurements for the forward pressure transfer function at high frequencies, a second model in which a lossless transmission line model of the tympanic membrane is appended to the original model is proposed. Two-port transmission matrix parameter results from this second model were compared with results from previously developed models of the guinea pig, cat, and human middle ears. Model results and published experimental data for the two-port transmission matrix parameters are found to be qualitatively similar between species. Quantitative differences in the two-port transmission matrix parameters suggest that the ossicular chains of chinchillas, cats, and guinea pigs are less flexible than in humans.

Examination of middle-ear function through interspecies comparison of middle-ear transmission characteristics

Lumped parameter ossicular chain models for several mammals have been developed; by comparing model parameters and the input and output characteristics of these models, conclusions can be drawn about the relative middle-ear transmission characteristics between different species allowing for a better understanding of the middle-ear’s overall role in hearing. The tympanic membrane plays a significant role in middle-ear function: experiments show that the forward and reverse transmission characteristics of the middle-ear are affected by the tympanic membrane, especially at high frequencies. Thus, understanding the behavior and transmission characteristics of the tympanic membrane is vital in understanding overall transmission through the middle-ear. By examining the interaction between lumped parameter ossicular chain models and tympanic membrane models from several animals and by comparing normalized two-port matrix parameters from several species, observations regarding differences in middle-ear behavior b...