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This comment pertains to the novel modified sub-ODE method introduced in the aforementioned paper. We have established, through a straightforward calculation, that the method employed in the paper is flawed. Moreover, certain exact solutions, as presented in the paper, are also erroneous in the context of both the auxiliary equation method associated with the aforementioned method and the model under investigation, namely the nonlinear low-pass electrical transmission lines model. It is noteworthy that the authors of the paper have asserted on two occasions that they meticulously validated all derived solutions by re-substituting them into the relevant equations, utilizing the Mathematica software. [ABSTRACT FROM AUTHOR]

Purpose: The fractal and fractional calculus have obtained considerable attention in the electrical and electronic engineering since they can model many complex phenomena that the traditional integer-order calculus cannot. The purpose of this paper is to develop a new fractional pulse narrowing nonlinear transmission lines model within the local fractional calculus for the first time and derive a novel method, namely, the direct mapping method, to seek for the nondifferentiable (ND) exact solutions. Design/methodology/approach: By defining some special functions via the Mittag–Leffler function on the Cantor sets, a novel approach, namely, the direct mapping method is derived via constructing a group of the nonlinear local fractional ordinary differential equations. With the aid of the direct mapping method, four groups of the ND exact solutions are obtained in just one step. The dynamic behaviors of the ND exact solutions on the Cantor sets are also described through the 3D graphical illustration. Findings: It is found that the proposed method is simple but effective and can construct four sets of the ND exact solutions in just one step. In addition, one of the ND exact solutions becomes the exact solution of the classic pulse narrowing nonlinear transmission lines model for the special case 9 = 1, which strongly proves the correctness and effectiveness of the method. The ideas in the paper can be used to study the other fractal partial differential equations (PDEs) within the local fractional derivative (LFD) arising in electrical and electronic engineering. Originality/value: The fractional pulse narrowing nonlinear transmission lines model within the LFD is proposed for the first time in this paper. The proposed method in the work can be used to study the other fractal PDEs arising in electrical and electronic engineering. The findings in this work are expected to shed a light on the study of the fractal PDEs arising in electrical and electronic engineering. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of the paper is the simulation of nonuniform transmission lines. Design/methodology/approach: The method involves a Magnus expansion and a numerical Laplace transform. The method involves a judicious arrangement of the governing equations so as to enable efficient simulation. Findings: The results confirm an effective and efficient numerical solver for inclusion of nonuniform transmission lines in circuit simulation. Originality/value: The work combines a Magnus expansion and numerical Laplace transform algorithm in a novel manner and applies the resultant algorithm for the effective and efficient simulation of nonuniform transmission lines. [ABSTRACT FROM AUTHOR]

If you come across an injured bird, the first step is to determine if it's alive, since stunned birds can sometimes appear dead. Leave your find undisturbed for about an hour, then listen: "If you hear that bird tap-dancing around inside, he's feeling better", McMahon says. "Our voices and our handling and our petting - things that may be soothing to our pets at home - are not the same for these wild animals", says Sunny Kellner, wildlife rehabilitation and outreach specialist at Sharon Audubon Center. [Extracted from the article]

Purpose: Renewable energy sources such as solar photovoltaic (PV) and wind are ubiquitous because of their lower environmental impact. Output from solar PV and wind turbines is unstable; hence, this article aims to propose an effective controller to extract maximum available power. Design/methodology/approach: By focusing on the varying nature of solar irradiance and wind speed, the paper presents the maximum power point tracking (MPPT) technique for renewable energy sources, and power regulation is made by the novel inverter design. Moreover, a DC–DC boost converter is adopted with solar PV, and a doubly fed induction generator is connected with the wind turbine. The proposed MPPT technique is used with the help of a rain optimization algorithm (ROA) based on bi-directional long short-term memory (Bi-LSTM) (ROA_Bi-LSTM). In addition, the sinusoidal pulse width modulation inverter is used for DC–AC power conversion. Findings: The proposed MPPT technique has jointly tracked the maximum power from solar PV and wind under varying climatic conditions. The power flow to the transmission line is stabilized to protect the load devices from unregulated frequency and voltage deviations. The power to the smart grid is regulated by three-level sinusoidal pulse width modulation inverter. Originality/value: The methodology and concept of the paper are taken by the author on their own. They have not taken a duplicate copy of any other research article. [ABSTRACT FROM AUTHOR]

Purpose: The paper is concerned with interpolatory proper orthogonal decomposition (IPOD) methods for nonlinear transmission line circuits. This paper aims to examine several factors that must be considered when applying such model reduction techniques to this kind of circuit. Design/methodology/approach: Two types of POD will be implemented. In each case, the choice of the order of the reduced model and the order of the interpolation space shall be considered. The stability of the models shall be explored. Findings: The results indicate that the order for the reduced model to obtain accurate results depends on the chosen method when considering nonlinear transmission lines. The results also indicate that the structure of the nonlinear transmission line is crucial for determining the stability of the reduced models. Originality/value: The work compares two IPOD methods and discusses the issues involved in achieving an accurate and stable reduced-order model for a nonlinear transmission line. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to establish the mathematical model and solve the complex calculation multi-field coupling problem for an electromagnetic overhead transmission line galloping excitation test system. Design/methodology/approach: An electromagnetic excitation test system is introduced. To calculate the vibration response of the transmission line, a transient coupled finite element model containing electromagnetic repulsive mechanism and transmission line system was established. Considering the advantages of Newmark-ß algorithm and fourth-order Runge–Kutta algorithm, the two algorithms are combined to solve the model. Compared with the simulation results of existing commercial finite element software, the accuracy of the calculation model of electromagnetic force and wire vibration response are verified. Findings: Comparison results show that the proposed calculation model can accurately obtain the force of electromagnetic mechanism and the vibration response of the overhead power lines, and improve the calculation efficiency. The calculation results show that vibration under electromagnetic excitation presents a double half-wave mode, and the galloping amplitude varies according to the charging voltage. Originality/value: This paper built the transient simulation model for a galloping test system. The Newmark-ß algorithm and the fourth-order Runge–Kutta algorithm are used to solve the model. The research results are of great significance for the actual galloping test system design. [ABSTRACT FROM AUTHOR]

Recent studies on integrated circuits interconnections are mainly concentrated on the analysis of crosstalk and delay, by taking the trade-off between accuracy, speed, and complexity into consideration. The new idea of this paper is to apply the convex optimization method to analyze crosstalk and delay of the lossy coupled interconnections in identical and non-identical forms. For this purpose, a simple and comprehensive model is proposed to cover the functional and dynamic crosstalk in a computationally-effective way. More specifically, various case studies are determined to analyze the transient response of the coupled transmission lines with arbitrary excitation sources in the presence of both capacitive and inductive coupling characteristics. To validate the model, the numerical and Advanced Design System (ADS) simulation results are compared to indicate the desired accuracy. The calculated crosstalk percentage error of the proposed model with respect to ADS and HSPICE are less than 1.03% and 1.19%, respectively. In addition, the computational speed of the proposed method is about twice higher than ADS and HSPICE. The proposed model is extendible to handle ${N}$ coupled lines, making it appropriate to model complex integrated circuit interconnections. [ABSTRACT FROM AUTHOR]

Power systems are subject to stochastic faults and process random noise. The faults (due to e.g. lightning strokes) can be temporary or permanent. When a lightning stroke hits a transmission line, the circuit breakers open to clear the fault and reclose. The resulting parameters changes are modelled as a discrete-time Markov jumps in this paper using the practical statistical failure rates. System parameters are also subject to random noise e.g. line reactance's depend on the conductors spacing which in turn depends on stochastic wind speeds. This paper presents a novel power system excitation control robust against such stochastic uncertainties. The design is based on a derived sufficient condition in the framework of linear matrix inequalities (LMI), and the attracting ellipsoid approach. The effectiveness of the proposed control is tested on a multi-machine power system. [ABSTRACT FROM AUTHOR]

In this paper, self-matching rectifiers for enhanced input dynamic range are demonstrated. The method is based on an artificial transmission line, which consists of a stepped-impedance transmission line loaded with shunt varactors. The output DC voltage of the rectifier is fed back to the varactors to control the effective electrical length and characteristic impedance of the line. Because this bias voltage changes as the power input to the rectifier changes, a matching network that maintains impedance matching regardless of the input power can be developed without additional circuits, thus substantially improving the input dynamic range. The experimental results for prototype rectifiers show a dynamic range as wide as 25 dB with only a single Schottky diode, an improvement of 11 dB over the rectifier with a conventional matching scheme, in which the conversion efficiency remains above 50%. The effectiveness of the proposed method is also verified with the experimental results for rectennas based on the demonstrated rectifiers. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to enhance the line congestion and to minimize power loss. Transmission line congestion is considered the most acute trouble during the operation of the power system. Therefore, congestion management acts as an effective tool in using the available power without breaking the system hindrances or limitations. Design/methodology/approach: Over the past few years, determining the optimal location and size of the devices have pinched a great deal of consideration. Numerous approaches have been established to mitigate the congestion rate, and this paper aims to enhance the line congestion and minimize power loss by determining the compensation rate and optimal location of a thyristor-switched capacitor (TCSC) using adaptive moth swarm optimization (AMSO) algorithm. Findings: An AMSO algorithm uses the performances of moth flame and the chaotic local search-based shrinking scheme of the bacterial foraging optimization algorithm. The proposed AMSO approach is executed and discussed for the IEEE-30 bus system for determining the optimal location of single TCSC and dual TCSC. Originality/value: In addition to this, the proposed algorithm is compared with various other existing approaches, and the results thus obtained provide better performances than other techniques. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to propose a novel methodology for optimal voltage source converter (VSC) station installation in hybrid alternating current (AC)/direct current (DC) transmission networks. Design/methodology/approach: In this analysis, a unified power flow model has been developed for the optimal power flow (OPF) problem for VSC-based high voltage direct current (VSC-HVDC) transmission network and solved using a particle swarm optimization (PSO) algorithm. The impact of the HVDC converter under abnormal conditions considering N-1 line outage contingency is analyzed against the congestion relief of the overall transmission network. The average loadability index is used as a severity indicator and minimized along with overall transmission line losses by replacing each AC line with an HVDC line independently. Findings: The developed unified OPF (UOPF) model converged successfully with (PSO) algorithm. The OPF problem has satisfied the defined operational constraints of the power system, and comparative results are obtained for objective function with different HVDC test configurations represented in the paper. In addition, the impact of VSC converter location is determined on objective function value. Originality/value: A novel methodology has been developed for the optimal installation of the converter station for the point-to-point configuration of HVDC transmission. The developed unified OPF model and methodology for selecting the AC bus for converter installation has effectively reduced congestion in transmission lines under single line outage contingency. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to develop a reliable finite element algorithm based on the transmission line method (TLM) to solve the nonlinear problem in electromagnetic field calculation. Design/methodology/approach: In this paper, the TLM has been researched and applied to solve nonlinear iteration in FEM. LU decomposition method and the Jacobi preconditioned conjugate gradient method have been investigated to solve the equations in transmission line finite element method (FEM-TLM). The algorithms have been developed in C++ language. The algorithm is applied to analyze the magnetic field of a long straight current-carrying wire and a single-phase transformer. Findings: FEM-TLM is more effective than traditional FEM in nonlinear iteration. The results of FEM-TLM have been compared and analyzed under different calculation scales. It is found that the LU decomposition method is more suitable for FEM-TLM because there is no need to repeatedly assemble the global coefficient matrix in the iterative solution process and it is not affected by the disturbance of the right-hand vector. Originality/value: An effective algorithm is provided for solving nonlinear problems in the electromagnetic field, which can save a lot of computing costs. The efficiency of LU decomposition and CG method in FEM-TLM nonlinear iteration is investigated, which also makes a preliminary exploration for the research of FEM-TLM parallel algorithms. [ABSTRACT FROM AUTHOR]

The theory of bifurcation is applied to generate chirp of the soliton within a nonlinear electrical lattice featuring next-neighbor couplings. By employing the reductive perturbation method, we derive the Chen–Lee–Liu equation, thereby obtaining the nonlinear system in a planar form. Bifurcation analysis of the phase portraits is conducted to demonstrate the emergence of homoclinic and heteroclinic orbits from the equilibrium points. These orbits serve as evidence that the nonlinear electrical network with neighbor couplings supports a diverse range of wave phenomena, including bright, dark, kink, and double-kink waves, as well as periodic waves. Furthermore, an external force is introduced to investigate the chaotic, quasi-periodic and time-dependent behaviors within the nonlinear system. It becomes evident that both the phase portraits and the time-dependent waveforms are highly responsive to variations in the amplitude of the external force. Finally, it is noteworthy that the Chen–Lee–Liu equation derived in the electrical network with neighbor couplings sheds light on dynamic behaviors reminiscent of those observed in models such as the helicoidal Peyrard–Bishop–Dauxois model of deoxyribonucleic acid and anharmonic lattices (Djine et al., 2023; Tchakoutio Nguetcho et al., 2017). • The paper investigates the dynamics of modulated waves in a nonlinear electrical transmission line lattice with next-neighbor couplings. • The reductive perturbation method is used to derive the generalized Chen–Lee–Liu equation with cubic nonlinearity. • Bifurcation of the phase portraits is investigated, revealing the existence of homoclinic and heteroclinic orbits. • The chaotic behavior and time-dependent waveforms of the system are explored using an external force. • The chirped soliton solutions of the generalized Chen–Lee–Liu equation are derived, including bright, dark, and double-kink solitons. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to build a neural network (NN) inverse model for the multi-band unequal-power Wilkinson power divider (WPD). Because closed-form expressions of the inverse input–output relationship do not exist, the NN becomes an appropriate choice, because it can be trained to learn from the data in inverse modeling. The design parameters of WPD are the characteristic impedances, lengths of the transmission line sections and the isolation resistors. The design equations used to train the NN inverse model are based on the even–odd mode analysis. Design/methodology/approach: An inverse model of a multi-band unequal WPD using NNs is presented. In inverse modeling of a microwave component, the inputs to the model are the required electrical parameters such as reflection coefficients, and the outputs of the model are the geometrical or the physical parameters. Findings: For verification purposes, a quad-band WPD and a penta-band WPD are designed. The results of the full-wave simulations verify the validity of the design procedure. The resulting NN model outperforms traditional time-consuming optimization procedures in terms of computation time with acceptable accuracy. The designed WPDs using NN are implemented by microstrip lines and verified by using full-wave analysis based on high-frequency structure simulator (HFSS). The results of the microstrip WPDs have good agreements with the corresponding results obtained by using ideal transmission line sections. Originality/value: The associated time-consuming procedure and computational burden in realizing WPD through optimization are major disadvantages; needless to mention the substantial increase in optimization time because of the multi-band design. NNs are one of the best candidates in addressing the abovementioned challenges, owing to their ability to process the interrelation between electrical and geometrical/physical characteristics of the WPD in a superfast manner. [ABSTRACT FROM AUTHOR]

The operating state of insulators is directly related to the stability of power transmission line. The existing methods for insulator state recognition cannot achieve satisfactory performance. In this paper, the self-blast state recognition of glass insulators is investigated by using an adaptive learning representation. To increase the adaptability of the network to different scales, we propose a solution based on multi-scale information throughout the entire process, beginning from a low-scale to high-scale subnetworks. The multi-scale information is aggregated in parallel way to take advantage of rich information representation. Then, an imitation of the human thinking pattern is employed. Utilizing entropy-based cost function, we update the parameters of the learner model in real-time. Based on the constraint of the evaluation index, adaptive depth representation for training glass insulators that are unsatisfied with the reliability evaluation is constructed to realize the self-optimizing regulation of feature space. Correspondingly, a stochastic configuration networks (SCNs) classifier is re-constructed to fit for the update multi-hierarchies knowledge space to carry out the re-recognition process. Finally, fuzzy integration is employed to ensemble multi-hierarchies network to improve the model's generalization. The recognition results on aerial dataset of insulators images demonstrate the effectiveness of our proposed approach. [ABSTRACT FROM AUTHOR]

This article discusses methods of parametric and structural-parametric synthesis of resonators, which contain transmission line segments of the same length. These methods allow optimizing resonators of various configurations with different segments number $N$ and characteristic impedances $Z_{0i}$. We will call optimal resonators if they have a minimum ratio $m = Z_{\mathrm {0max}}/Z_{\mathrm {0min}}$ at given ratio between the critical frequencies (poles and zeros of the input impedance). The input impedances of the resonators under consideration at the Richards’ frequency variable $S$ are described by the reactance functions of $N$ degree: $Z^{N}(S)$. The parametric synthesis refers to stepped impedance resonators (SIRs). The structural-parametric synthesis refers to resonators of a more general form, which contain open- and short-circuited stubs. The methods are based on two states established in this paper: the order of the reactance function $Z^{N}(S)$ should be the minimum possible ($N = N_{\mathrm {min}}$) to implement the required ratio between certain critical frequencies; the characteristic impedances of the composite sections $Z_{0i}$ take only two values $Z_{\mathrm {0min}}$ or $Z_{\mathrm {0max}}$. These methods were used to synthesize different resonators useful for practical application. With the help of the structural-parametric synthesis, the resonators of a more complex configuration are synthesized, which significantly exceed SIRs. The results of the measurements and simulation are presented. [ABSTRACT FROM AUTHOR]

Purpose: The fabrication of electromagnetic (EM) components may induce randomness in several design parameters. In such cases, an uncertainty assessment is of high importance, as simulating the performance of those devices via deterministic approaches may lead to a misinterpretation of the extracted outcomes. This paper aims to present a novel heuristic for the sparse representation of the polynomial chaos (PC) expansion of the output of interest, aiming at calculating the involved coefficients with a small computational cost. Design/methodology/approach: This paper presents a novel heuristic that aims to develop a sparse PC technique based on anisotropic index sets. Specifically, this study's approach generates those indices by using the mean elementary effect of each input. Accurate outcomes are extracted in low computational times, by constructing design of experiments (DoE) which satisfy the D-optimality criterion. Findings: The method proposed in this study is tested on three test problems; the first one involves a transmission line that exhibits several random dielectrics, while the second and the third cases examine the effects of various random design parameters to the transmission coefficient of microwave filters. Comparisons with the Monte Carlo technique and other PC approaches prove that accurate outcomes are obtained in a smaller computational cost, thus the efficiency of the PC scheme is enhanced. Originality/value: This paper introduces a new sparse PC technique based on anisotropic indices. The proposed method manages to accurately extract the expansion coefficients by locating D-optimal DoE. [ABSTRACT FROM AUTHOR]

The objective of this paper is to demonstrate that the use of a distributed approach for the design of the inductance of an LC-tank millimeter-wave (mm-wave) voltage-controlled oscillator (VCO) can lead to higher performance. Performance is improved in both frequency tuning range and power consumption thanks to a reduction of the cross-coupled pair size. The direct comparison of VCOs designed in different technologies is not straightforward, since the performance of the varactors and the inductance widely differ for different fabrication technologies. Hence, two VCOs were designed and integrated in the same CMOS 55-nm technology by using the same varactors. A “classical” VCO using an inductor available in the technology and serving as reference, and a distributed-inductance-based VCO using a slow-wave transmission line were considered. A detailed and efficient approach is adopted for the synthesis of slow-wave transmission line-based inductance without using time-consuming EM simulations. The slow-wave VCO permits to limit the overall size linked to a distributed approach while improving the electrical performance. The experimental results on the proof-of-concept demonstrators at a working frequency of 77 GHz allow validating our proposal. [ABSTRACT FROM AUTHOR]

Implementing flexible, software-defined duplexing transceivers remains challenging due to the inherent self-interference from TX to RX that requires cancellation in the RF/analog domain. Previously, we presented a novel, duplexing, integrated, single antenna transceiver architecture that used an M-stage distributed amplifier combined with an artificial transmission line to achieve high transmit-receive isolation across more than an octave in center frequency. In this paper, we explain and explore the trade-offs and limits on this class of distributed, duplexing transceivers as a function of system and sub-circuit parameters. [ABSTRACT FROM AUTHOR]

In this paper we study a sensitivity function of resonance frequencies to capacitance change in resonators with capacitive tuning, which characterizes the local tunability. This function is a circuit function, similar to the input and transmission functions. The features of the sensitivity function, leading to tunability increasing, are defined. The founded features are used to construct resonators from segments of transmission lines with an extended tuning range. The tunability limitations of resonators tunable by one or several capacitors are determined. Synthesized transmission line resonators can be used in tunable bandpass filters. They allow the filter to be tuned over a wider frequency range for a given capacitance change ${C} _{\max }/{C} _{\min }$. If the tuning range is specified, the filter will perform the adjustment at a lower ratio ${C} _{\mathrm {max}}/{C} _{\min }$. This leads to a smaller change in the insertion loss of the filter in a given frequency range. [ABSTRACT FROM AUTHOR]

The tunability in phase characteristics becomes more and more important in the modern wireless communication system. However, the existing phase tunable coupler structures suffer from the narrow bandwidth and limited tunable range due to the much more complex design requirements. The further deterioration in performance occurs when additional tunability in operating frequency is considered. In this paper, a new simultaneously phase- and frequency- tunable coupler is proposed with the enhancement in both bandwidth and phase tunable range. Two tunable capacitors are loaded on the two terminals of a coupled line section to realize a novel tunable transmission line. This tunable element is introduced between two quarter-wavelength coupled line sections to implement the simultaneous tunability in both phase and operating frequency. For demonstration purpose, a highly flexible 3 dB coupler was designed, fabricated and measured. For a fixed operating frequency of 2.4 GHz, the coupler can provide a continuously tunable phase difference from 30° to 150° within a 10% bandwidth. For a standard phase difference of 90°, the operating frequency of the same coupler can be varied from 2.0 GHz to 2.75 GHz. Good performance in return loss, isolation, and output amplitude imbalance is achieved for all these states. [ABSTRACT FROM AUTHOR]

This paper presents the analysis of magnetic LC (MLC) resonators loaded with differential microstrip transmission lines. The analysis is based on an equivalent circuit model describing the electromagnetic behavior of the MLC resonators. It is shown that a pair of microstrip lines loaded with MLC resonators exhibit a dual-mode bandstop response in the common mode of operation, while being transparent to the differential signals. This characteristic can be used in the design of differential transmission lines with wideband common mode suppression. Circuit models together with Bloch theorem are applied for the systematic design, where the dispersion analysis helps to estimate the maximum achievable common-mode rejection bandwidth. A systematic design procedure is developed for designing differential transmission lines using this method. The theoretical analysis is validated by designing and measuring a balanced transmission line using three cascaded MLC-based cells. The measurements exhibit more than 40-dB common-mode signal suppression for a fractional bandwidth of 32% around 1.3 GHz, whereas the fraction bandwidth for 20-dB suppression level is 57.5%. The fabricated prototype has a compact size of $0.09\lambda _{g}\times 0.37\lambda _{g}$ , where $\lambda _{g}$ is the guided wavelength at 1.3 GHz. A detailed comparison between the designed MLC-based differential transmission line and the state-of-the-art designs shows a superior performance of the MLC-based transmission lines in terms of size, fabrication simplicity, and the common-mode rejection level. [ABSTRACT FROM AUTHOR]

This paper addresses the recursive minimum-variance filtering problem for a class of two-dimensional shift-varying systems with stochastic nonlinearity and degraded measurements. The stochastic nonlinearity is governed by its statistical characteristics and the degraded measurements reflect the signal degradation obeying certain prescribed probabilistic distributions. The main objective of this paper is to construct a two-step recursive filter that achieves the minimum error variance of the state estimation at each step. Utilizing an inductive approach, unbiasedness of the proposed filter is first ensured and the parameters of the filter are then designed by resorting to the completing squares method. Subsequently, the filtering performances including the boundedness and the monotonicity are investigated with respect to the measurement degradations through mathematically rigorous analysis. Moreover, a computational algorithm is presented to facilitate the online implementation of the designed filter. Finally, numerical simulation illustrates the effectiveness and applicability of the proposed filtering scheme in the state estimation problem for monitoring a long transmission line in circuit systems. [ABSTRACT FROM AUTHOR]

In this corrigendum, we would like to point out that we have the solutions in the above paper for the cases A = B = 0 (which are all correct seven cases) when using the new modified sub-ODE method. This correction do not alter the conclusion of the article. [ABSTRACT FROM AUTHOR]

In this paper, a new phase error analysis is introduced for rotary traveling wave oscillators (RTWOs). Two new analytical approaches are used to extract closed-form equations for the RTWOs phase error arising from asymmetric resonator and inequality of negative transconductors. Derived equations show that the phase error can be cancelled and even controlled by adjusting the bias current of negative transconductors without any undesirable changing in oscillation frequency. This characteristic is then used for introducing a new phase error calibration method for RTWOs. This calibration method is not limited by the problems that limit the usage of the prior calibration technique. Our theoretical results are compared with accurate simulations to evaluate the validity of the proposed analysis and accuracy of the closed-form equations. Simulations have been done in 0. 18- $\mu$ m CMOS technology with a 1.8-V supply voltage. The evaluations show good agreement between analytical phase-error equations and simulation results. Also, appropriate simulations confirm the validity of the calibration method that is introduced in this paper. [ABSTRACT FROM AUTHOR]

In this paper, a dual-band transmission-line resistance compression network (TLRCN) is introduced and applied to the rectifier design to enhance the power conversion efficiency at low input power levels, leading to wider dynamic power range of the rectifier. It can be used to reduce the sensitivity of the rectifying efficiency to input power variation at two frequencies. The analytical expressions for the dual-band TLRCN are derived. In order to validate the proposed idea, two dual-band rectifiers with different frequency spacing ($\Delta f$) are designed, fabricated, and measured. One works at 0.915 GHz/2.45 GHz ($\Delta f = 1.535$ GHz) and the other at 1.80 GHz/2.40 GHz ($\Delta f = 0.6$ GHz). For comparison, their counterparts, without the dual-band TLRCN, are also designed and implemented. The measured results show that the proposed dual-band TLRCN can be used to extend the input power range at two frequencies without decreasing the maximum power conversion efficiencies. [ABSTRACT FROM AUTHOR]

This paper presents an integral equation formulation for the calculation of the propagation characteristics of plasmonic transmission lines embedded within a multi-layered structure. The Method of Moments (MoM) technique is adopted in this paper due to its superior advantages over other techniques including the finite difference and finite element methods. Plasmonic transmission lines consist of a number metallic strips of arbitrary shapes immersed within a stack of planar dielectric or metallic layers. These transmission lines can support one or more mode, each of which has its characteristic mode profile and it propagates with a certain propagation and attenuation constants. The developed solver is tested for different plasmonic transmission line topologies surrounded by various layered media. The obtained results are compared to CST commercial software for verification. Very good agreement between the proposed solver and CST has been observed. The developed MoM solver requires much smaller number of unknowns if compared with those based on Finite Difference Time Domain (FD-TD) or Finite Element Method (FEM) such as Lumerical and CST. [ABSTRACT FROM AUTHOR]

This paper focuses on the small-signal stability analysis of systems modelled as differential-algebraic equations and with inclusions of delays in both differential equations and algebraic constraints. The paper considers the general case for which the characteristic equation of the system is a series of infinite terms corresponding to an infinite number of delays. The expression of such a series and the conditions for its convergence are first derived analytically. Then, the effect on small-signal stability analysis is evaluated numerically through a Chebyshev discretization of the characteristic equations. Numerical appraisals focus on hybrid control systems recast into delay algebraic-differential equations as well as a benchmark dynamic power system model with inclusion of long transmission lines. [ABSTRACT FROM AUTHOR]

Purpose The purpose of this paper is to analyze a signal propagation in highly metalized environments, which has not been extensively studied in the literature. Having in mind a large number of such applications, better understanding and possibly finding a way of improving communication in these conditions would be highly beneficial.Design/methodology/approach The analysis is performed in a simulation environment developed by the authors, based on finite difference time domain (FDTD) method, to identify effects that have decisive influence on electromagnetic (EM) wave propagation in the aforementioned conditions. The analysis of the EM field at the reception is modified so that a multiple-field sampling is performed, and maximal values are further used. In practical realizations, this procedure could be implemented by using multiple antennas and selective combining at the reception.Findings Results show that the existence of metal objects (in the observed case, these are railway tracks), in combination with the appropriate choice of antenna parameters, can be favorably used to improve signal reception. The contribution is manifested through the reduction of the pathloss.Research limitations/implications In the performed analysis, one should be aware of the limitations that the FDTD method brings. Those limitations are related to the size of the computational domain and discretization mesh refinement (possibility of modeling geometry in fine details).Originality/value Originality of this paper consists of the introduced modification in the analysis of signal propagation in heavily metalized environment. Namely, a multiple-field sampling in the reception zone (in one plane, dimensions λ × λ = 12.5 cm X 12.5 cm) is performed using several probes in simulation environment. In this way, a qualitative analysis is performed more efficiently, which made it is possible to distinguish and identify different propagation mechanisms. [ABSTRACT FROM AUTHOR]

An 8.5-Gb/s/link non-contact multi-drop bus is presented. The signal reflections that limit the data rates of conventional multi-drop bus interfaces are dramatically reduced by using transmission line couplers at each signal branching point. As an energy-equipartitioned technique provides the same signal level to every port, wider receiver margin is achieved. The data rate is improved by 1.8 times compared to the most advanced multi-drop bus interface. The theoretical analysis and design techniques of energy-equipartitioned transmission line couplers are discussed in this paper. The design methodologies were verified through simulations performed by using a full-3D EM-simulator and experiments with FR4 test boards. Due to the low-cut characteristics of the couplers, the low-frequency components are cut off so that differentiated pulses arrive at the receiver input point. A receiver detects and recovers the received pulses by integrating them using hysteresis characteristics. The design techniques of the transceiver for the transmission line couplers are also discussed in this paper. The proposed methods were verified by using a test chip fabricated with a 90-nm CMOS process. Experiments with a prototype of an eight-drop multi-drop bus system confirmed BER < 10^-14 at a data rate of 8.5-Gb/s/link. The measured timing margin at the far-end module was 0.49-UI at a BER of 10^-12. The power consumption of the transceiver was 75.6-mW at a supply voltage of 1.2-V. [ABSTRACT FROM PUBLISHER]

Purpose: The purpose of this paper is to investigate the simultaneous effects of ionization and dispersion of soil on the impulse behavior of grounding electrodes under first and subsequent stroke currents. Design/methodology/approach: A recently introduced technique called improved multi-conductor transmission line (MTL) is simplified for grounding electrodes buried in both-affected soils. Findings: The simulation results show that including the two effects simultaneously in highly resistive soils under high-valued subsequent stroke current is recommended. Otherwise, simultaneous effects can be disregard. Originality/value: To the best of the authors' knowledge, there is no research on sensitivity analyses for the simultaneous inclusion of the two effects on the effective length and the induced voltage on the soil surface. To this end, the simplified MTL is applied to the grounding electrodes. The simulation results show that the computational efficiency in comparison with previous methods is, first, considerably increased. Second, the simultaneous effects result in decreasing the soil surface voltage with respect to situations where either ionization or dispersion is taken into account (single-affected soils). In other words, the performance of grounding systems is improved. Third, the effective length in both-affected soil is has a middle value with respect to the single-affected soil. Such findings practically and financially are of importance. [ABSTRACT FROM AUTHOR]

• The interlaced group convolution strategy is employed to reconstruct the convolutional layers of the Inception network, which reduces the redundancy of convolutional kernels in the channel extent. • To avoid the redundancy of feature maps, the feature space with discrimination is reconstructed. • SCNs ensures the universal approximation property of the model. • The objective function can evaluate the uncertain results of the self-blast states of glass insulator images in real time. • The dynamic transfer learning mechanism improves the detection accuracy of the model. The self-blast state of a glass insulator directly affects the safety and reliability of transmission lines. To address the insufficient generalization ability of existing detection methods for insulator self-blast states and the drawbacks of deep neural network structures, the theories of transfer learning and closed-loop control are drawn upon to provide an intelligent detection method for the self-blast states of glass insulators. The method proposed in this paper is based on stochastic configuration networks and a feedback transfer learning mechanism. First, to reduce the redundancy of convolutional kernels in the channel extent, the interleaved group convolution strategy is employed to reconstruct the convolutional layers of the Inception network. Second, in view of the different feature applicabilities of different glass insulator images and based on the adaptive convolution module groups, the data structure of the dynamic feature space of insulator images is built with a certain mapping relationship from global to local. Then, the discriminative measure index is used to evaluate the discriminative information of the feature space to enhance the interpretability of the compact feature spance. Third, the fully connected feature vector of the compact feature space is sent to stochastic configuration networks (SCNs), which have universal approximation property to establish the classification criteria of the self-blast states of insulator images with generalization ability. Finally, an imitation of human thinking patterns is employed that exhibits repeated deliberation and comparison. Consequently, based on generalized error and entropy theories, the evaluation index of the objective function is established to evaluate the uncertain detection results of the self-blast states of glass insulator images in real time. Then, the dynamic transfer learning mechanism is constructed based on the constraint of the measurement index of uncertain detection results to realize self-optimizing regulation of the feature space that exhibits multihierarchy and discrimination and reconstructed classification criteria. The experimental results show that compared with other algorithms, the proposed method enhances the generalization ability and detection accuracy of the model. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to propose a physics-aware algorithm to obtain radio frequency (RF)-reduced models of micro-electromechanical systems (MEMS) switches and show how, together with multiphysics macromodels, they can be realized as circuits that include both lumped and distributed parameters. Design/methodology/approach: The macromodels are extracted with a robust procedure from the solution of Maxwell's equations with electromagnetic circuit element (ECE) boundary conditions. The reduced model is extracted from the simulations of three electromagnetic field problems, in full-wave regime, that correspond to three configurations: signal lines alone, switch in the up and down positions. Findings: The technique is exemplified for shunt switches, but it can be extended for lateral switches. Moreover, the algorithm is able take frequency dependence into account both for the signal lines and for the switch model. For the later, the order of the model is increased until a specified accuracy is achieved. Originality/value: The use of ECE as boundary conditions for the RF simulation of MEMS switches has the advantage that the definition of ports is unambiguous and robust as the ports are clearly defined. The extraction approach has the advantage that the simplified model keeps the basic phenomena, i.e. the propagation of the signal along the lines. As the macromodel is realized with a netlist that uses transmission lines models, the lines' extension is natural. The frequency dependence can be included in the model, if needed. [ABSTRACT FROM AUTHOR]

Purpose The paper aims to discuss problems of power and energy losses in a double-circuit overhead transmission line. It was observed from energy meters’ readings, that in such a line, active power losses can be measured as “negative”. The “negative” active power losses appear when the active power injected to the circuit is lower than the active power received at the circuit end. The purpose of this paper is to explain this phenomenon.Design/methodology/approach Theoretical considerations based on mathematical model of the transmission line of π-type confirming that effect are presented. Power losses related to series impedance of the line and to shunt admittance are calculated. The theoretical considerations are confirmed by measurements done on the real transmission line.Findings The calculations allow to indicate components of the active power losses, i.e. related to electromagnetic coupling among wires of a given circuit, related to electromagnetic coupling between circuits and related to shunt capacitance asymmetry. The authors indicate the influence of the line/wires geometry on the active power losses in a double-circuit overhead transmission line.Originality/value Explanation of the effect of “negative” active power losses’ measurement in a double-circuit overhead transmission line is provided in this paper. [ABSTRACT FROM AUTHOR]

This paper addresses for the first time the issue of passivity of the circuit models produced by means of the generalized polynomial chaos technique in combination with the stochastic Galerkin method. This approach has been used in literature to obtain statistical information through the simulation of an augmented but deterministic instance of a stochastic circuit, possibly including distributed transmission-line elements. However, transient simulations raise the critical question as to whether such an augmented network is passive or not. This paper discusses the general requirements for the augmented circuits to be passive and provides a sufficient condition for their passivity. Some numerical examples illustrate the theoretical results and conclude the paper. [ABSTRACT FROM PUBLISHER]

The article provides an optimal synthesis of nonuniform transmission line structural elements, where resonant frequencies have a special placement. It is possible to improve the functionality of dual-mode resonators, which use these transmission segments. The optimal synthesis means that we obtain the special ratio between resonance frequencies of structural elements and have the minimum of parameter ${m}={Z}_{\text {0max}}/{Z}_{\text {0min}}$. We used the parametric synthesis for optimize proposed structure. It leads to stepped-impedance transmission line segments (SILS) which have the resonant frequencies with required placement and ${m}= {m}_{\text {min}}$. Two SILS pairs are synthesized. Two ends of one pair are open-circuited and the other pair is short-circuited. We added different stubs to the middle of proposed SILS. As result, four new dual-mode resonators with enhanced functions are designed. All dual-mode resonators have an extended stopband. The dual-mode resonators have reduced length relative to a half-wave resonator. The resonators allow increasing their operating frequencies. These resonators are very promising for use in dual-band BPF, so we can change the placement of one passband to another in the range $1.46 \le {f}_{2}/{f}_{1} \le 6.47$. The measured and simulated results of two microstrip filters with new structural elements are offered. [ABSTRACT FROM AUTHOR]

Existing smart grid security research investigates different attack techniques and cascading failures from the attackers’ viewpoints, while the defenders’ or the operators’ protection strategies are somehow neglected. Game theoretic methods are applied for the attacker–defender games in the smart grid security area. Yet, most of the existing works only use the one-shot game and do not consider the dynamic process of the electric power grid. In this paper, we propose a new solution for a multistage game (also called a dynamic game) between the attacker and the defender based on reinforcement learning to identify the optimal attack sequences given certain objectives (e.g., transmission line outages or generation loss). Different from a one-shot game, the attacker here learns a sequence of attack actions applying for the transmission lines and the defender protects a set of selected lines. After each time step, the cascading failure will be measured, and the line outage (and/or generation loss) will be used as the feedback for the attacker to generate the next action. The performance is evaluated on W&W 6-bus and IEEE 39-bus systems. A comparison between a multistage attack and a one-shot attack is conducted to show the significance of the multistage attack. Furthermore, different protection strategies are evaluated in simulation, which shows that the proposed reinforcement learning solution can identify optimal attack sequences under several attack objectives. It also indicates that attacker’s learned information helps the defender to enhance the security of the system. [ABSTRACT FROM AUTHOR]

In this paper, we consider the problem of placing energy storage resources in a power network when all storage devices are optimally controlled to minimize system-wide costs. We propose a discrete optimization framework to accurately model heterogeneous storage capital and installation costs as these fixed costs account for the largest cost component in most grid-scale storage projects. Identifying an optimal placement strategy is challenging due to the combinatorial nature of such placement problems, and the spatial and temporal transfers of energy via transmission lines and distributed storage devices. To develop a scalable near-optimal placement strategy with a performance guarantee, we characterize a tight condition under which the placement value function is submodular by exploiting our duality-based analytical characterization of the optimal cost and prices. The proposed polyhedral analysis of a parametric economic dispatch problem with optimal storage control also leads to a simple but rigorous verification method for submodularity, and the novel insight that the spatiotemporal congestion pattern of a power network is critical to submodularity. A modified greedy algorithm provides a $(1-1/e)$ -optimal placement solution and can be extended to obtain risk-aware placement strategies when submodularity is verified. [ABSTRACT FROM AUTHOR]

The delay tolerant network (DTN) is an emerging concept, which is used to describe the network, where the communication link may disrupt frequently. To cope with this problem, the DTN uses the store-carry-forward (SCF) transmission mode. With this policy, the messages in the DTN are transmitted based on the nodes' cooperation. However, the nodes may be selfish, so the source has to pay certain rewards for others to get their help. This paper studies the optimal incentive policy to maximize the source's final utility. First, it models the message spreading process as several ordinary differential equations (ODEs) based on the meanfield approximation. Then, it mathematically gets the optimal policy and explores the structure of the policy. Finally, it checks the accuracy of the ODEs model and shows the advantages of the optimal policy through simulation and theoretical results respectively. [ABSTRACT FROM AUTHOR]

Abstract In this paper, the problem of finite-horizon H ∞ state estimation is investigated for a class of discrete time-varying complex networks with multiplicative noises and random coupling strengths. The network nodes and estimators are connected via a constrained communication network which allows only one node to send measurement data at each transmission instant. The Round-Robin protocol is introduced to determine which node obtains the access to the network at certain transmission instant. The aim of the addressed problem is to design a set of time-varying estimator parameters such that the prescribed H ∞ performance is guaranteed over a finite horizon. By using the stochastic analysis approach and completing-the-square method, sufficient conditions are derived for the existence of the desired estimators in terms of the solution to backward recursive Riccati difference equations. Finally, a numerical example is provided to validate the feasibility and effectiveness of the proposed results. [ABSTRACT FROM AUTHOR]

Highlights • Kirchhoff's current law and Kirchhoff's voltage law were obtained. • We presented mathematical physical methods. • The nonlinear low-pass electrical transmission lines. • Modified Kudryashov method; Sine-Gordon equation expansion method. • Extended sinh-Gordon equation expansion method; Soliton and other solutions. Abstract This paper focuses on investigating soliton and other solutions using three integration schemes to integrate a nonlinear partial differential equation describing the wave propagation in nonlinear low–pass electrical transmission lines. By applying the Kirchhoff's laws and complex transformation, the nonlinear low–pass electrical transmission lines are converted into an equation wave propagation in nonlinear ODE low–pass electrical transmission lines. Later on, mentioned integration schemes viz modified Kudryashov method, sine–Gordon equation expansion method and extended sinh–Gordon equation expansion method are used to carry out new hyperbolic and trigonometric solutions which shows the consistency via computerized symbolic computation package maple. Various types of solitary wave solutions are derived including kink, anti-kink, dark, bright, dark-bright, singular, combined singular, and periodic singular wave soliton solutions. The corresponding three integration schemes are robust and effective for acquiring the new dark, bright, dark–bright, singular or combined singular and optical soliton solutions of the wave propagation in nonlinear low–pass electrical transmission lines. To show the real physical significance of the studied equation, some three dimensional (3D) and two dimensional (2D) figures of obtained solutions are plotted with the use of the Matlab software under the proper choice of arbitrary parameters. Moreover, all derived solutions were verified back into its corresponding equation with the aid of maple program. [ABSTRACT FROM AUTHOR]

Purpose The loading and power variations in the power system, especially for the peak hours have abundant concussion on the loading patterns of the open access transmission system. During such unconditional state of loading the transmission line parameters and the line voltages show a substandard profile, which depicts exaction of congestion management of the power line in such events. The purpose of this paper is to present an uncomplicated and economical model for congestion management using flexible AC transmission system (FACTS) devices.Design/methodology/approach The approach desires a two-step procedure, first by optimal placement of thyristor controlled series capacitor (TCSC) and static VAR compensator (SVC) as FACTS devices in the network; second tuning the control parameters to their optimized values. The optimal location and tuning of TCSC and SVC represents a hectic optimization problem, due to its multi-objective and constrained nature. Hence, a reassuring heuristic optimization algorithm inspired by behavior of cat and firefly is employed to find the optimal placement and tuning of TCSC and SVC.Findings The effectiveness of the proposed model is tested through simulation on standard IEEE 14-bus system. The proposed approach proves to be better than the earlier existing approaches in the literature.Research limitations/implications With the completed simulation and results, it is proved that the proposed scheme has reduced the congestion in line, thereby increasing the voltage stability along with improved loading capability for the congested lines.Practical implications The usefulness of the proposed scheme is justified with the computed results, giving convenience for implementation to any practical transmission network.Originality/value This paper fulfills an identified need to study exaction of congestion management of the power line. [ABSTRACT FROM AUTHOR]

Miniaturization is a promising trend for future RF identification (RFID) in many applications such as the Internet of Things (IoT) and implantable devices. For a small-sized RFID tag using near-field communication, the reader is required to emit a large amount of RF power in order to power up the tag while simultaneously picking up a weak backscattering communication signal. This results in a very small signal-to-blocker ratio (SBR), making the demodulation very difficult for the reader-side receiver (RSR). In this paper, we propose a novel blocker rejection technique based on inductive coupling. Several coupling coils and transmission lines are designed and optimized on the same printed circuit board (PCB) with the main power transmitting (Tx) coil of the reader, which leads to a much higher SBR. As a demonstration vehicle, a 200\ \mu\text m \times 200\ \mu\text m RFID tag with an on-chip antenna is fabricated using 65-nm CMOS technology with a harvested power of 12 $\mu $ W, an operating frequency of 2 GHz, and a backscattering data rate of 625 kb/s. Measured result shows the proposed block rejection technique improves the SBR by 44 dB. [ABSTRACT FROM PUBLISHER]

This paper presents the Chebyshev neural network (ChNN) as an improved artificial intelligence technique for power system protection studies and examines the performances of two ChNN learning algorithms for fault classification of series compensated transmission line. The training algorithms are least-square Levenberg–Marquardt (LSLM) and recursive least-square algorithm with forgetting factor (RLSFF). The performances of these algorithms are assessed based on their generalization capability in relating the fault current parameters with an event of fault in the transmission line. The proposed algorithm is fast in response as it utilizes postfault samples of three phase currents measured at the relaying end corresponding to half-cycle duration only. After being trained with only a small part of the generated fault data, the algorithms have been tested over a large number of fault cases with wide variation of system and fault parameters. Based on the studies carried out in this paper, it has been found that although the RLSFF algorithm is faster for training the ChNN in the fault classification application for series compensated transmission lines, the LSLM algorithm has the best accuracy in testing. The results prove that the proposed ChNN-based method is accurate, fast, easy to design, and immune to the level of compensations. Thus, it is suitable for digital relaying applications. [ABSTRACT FROM PUBLISHER]

Recently, by replacing the parallel LC “resonator” in Chua's circuit with a lossless transmission line that is terminated by a short circuit, a nonlinear transmission line oscillator is proposed and is named as a “time-delayed Chua's circuit.” In a transmission line oscillator, a linear wave travels along a piece of the transmission line and interacts with terminating electrical components, i.e., a boundary-value problem for a hyperbolic partial differential equation with boundary conditions. Furthermore, a fixed time delay arises due to the propagation time through the transmission line. Delay-induced dynamics are particularly important in technologies where high-speed computers must take into account transmission line effects including propagation delay to prevent undesirable self-oscillations. In this paper, the equation describing Chua's circuit with a lossless transmission line is reduced to a differential-difference equation with one delay (i.e., neutral-type differential equation). By using suitable Lyapunov functionals, we reduce the problem of stability and uniform ultimate boundedness to a scalar ordinary differential inequality. Soon afterwards, we derive conditions for global exponential stability of an equilibrium point. The oscillation of small amplitude in the system are studied by perturbation theory, and a general approach is presented for equations of this type for finding the expansion of the oscillation to any order in terms of the coefficient of the fundamental frequency. The frequency-amplitude relations are derived to second order. Finally, we also give some numerical examples to verify the correctness of our analytic results by computer simulations. [ABSTRACT FROM AUTHOR]

The performance characteristics of transmission lines, silicon integrated waveguides, tunable LC resonators and passive combiners/splitters and baluns are described in this paper. It is shown that Q-factor for an on-chip LC tank peaks between 20 and 40 GHz in a 65 nm RF-CMOS technology; well below the bands proposed for many mm-wave applications. Simulations also predict that the Q-factor of differential CPW transmission lines on-chip can exceed 20 at 60 GHz in RF-CMOS when a floating shield is applied, outperforming unshielded variants employing more advanced metal stacks. A PA circuit demonstrator for advanced on-chip passive power combiners, splitters and baluns realizes peak-PAE of 18% and Psat better than 20 dBm into a 50∼\Omega load at 62 GHz. An outlook to the enablement of digitally intensive mm-wave ICs and low-loss passive interconnections (0.15 dB/mm measured loss at 100 GHz) concludes the paper. [ABSTRACT FROM AUTHOR]

This paper introduces a qualitative revision of the traditional LC tank circuit in the fractional domain. The paper can be divided into six major parts, aiming in turn to establish the various conditions under which L\betaC\alpha impedance may act as a resistor, negative resistor, or a positive or negative pure imaginary inductor or capacitor, in accordance to new frequency definitions; illustrate the process by which the phase response chooses the shortest path from initial to final phase, and use this illustration to verify the cases discussed in part one; develop the generalized parameters for the bandpass filter response of the L\betaC\alpha circuit, such as the resonance frequency and quality factor versus \alpha - \beta plane; discuss sensitivity analyses with respect to the fractional orders, as well as the time domain analyses for the impulse and step responses with their analytical formulas; and lastly, to propose some possible applications for this generalized circuit. Mathematical and PSpice simulation results are included to validate the discussion. [ABSTRACT FROM PUBLISHER]

In this paper, analysis and synthesis approach for two new variants within the Class-EF power amplifier (PA) family is elaborated. These amplifiers are classified here as Class-E3F and transmission-line (TL) Class-E3F2. The proposed circuits offer means to alleviate some of the major issues faced by existing topologies such as substantial power losses due to the parasitic resistance of the large inductor in the Class-EF load network and deviation from ideal Class-EF operation due to the effect of device output inductance at high frequencies. Both lumped-element and transmission-line load networks for the Class-E3F PA are described. The load networks of the Class-E3F and TL Class-E3F2 amplifier topologies developed in this paper simultaneously satisfy the Class-EF optimum impedance requirements at fundamental frequency, second, and third harmonics as well as simultaneously providing matching to the circuit optimum load resistance for any prescribed system load resistance. Optimum circuit component values are analytically derived and validated by harmonic balance simulations. Trade-offs between circuit figures of merit and component values with some practical limitations being considered are discussed. [ABSTRACT FROM PUBLISHER]

Multicarrier modulations (MCMs) have been considered as a good means to combat the frequency-selective fading. In practice, the MCM idea has already been integrated in most of the modern communication applications, including power line communications (PLCs). However, even in the MCM conception, there still exist several proposals of different schemes that remain competing with each other. In this paper, we unveil a flexibility gain that can possibly be obtained from the coexistence of different MCMs. This flexibility is termed as “modulation flexibility,” meaning that we switch among different MCM schemes according to the transmission environment, and such idea can be eventually realized by a unified MCM transceiver. This paper includes a presentation of its efficient implementation as well as its performance evaluation. [ABSTRACT FROM PUBLISHER]