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A highly versatile broadband equivalent circuit model for arbitrary lossy wire networks including moderate radiation losses is presented. Based on a quasistatic Method-of-Moments-eigenvalue problem a modal multiport circuit is derived with minimal computational effort, offering fast convergence and inherent stability for time-domain simulations with arbitrary active/passive non-linear loads. The model...
The differences between the characteristic modes(CMs) and X modes(XMs) are pointed out then the relations between these two types of modes are discussed through an example of a thin strip dipole. Finally it is concluded that the resonant information of an antenna, including resonant frequency and resonant current, exists only in the imaginal part of the impedance operator (reactance operator) of the...
In this paper, the dc dynamic performance of VSC-HVDC systems is investigated using the frequency domain approach. In a previous work, it has been found through the eigenvalue analysis that, in some situations, the VSC-HVDC system becomes unstable when the converter which controls the direct-voltage injects power exceeding a certain value. However, the cause of the instability was not addressed. This...
In presented work, resonance properties of resonators formed by quasiperiodic Bragg reflectors are investigated by solution of some types of eigenvalue problems. In the first eigenvalue problem the values of complex eigenfrequencies are found for the decaying natural oscillations of the "cold" passive resonators. The other eigenvalue problems correspond to undamped oscillations in "hot"...
In the Tuoketuo project in North China, a phenomena of system destabilization was impressively recognized during the field test of the subsynchronous resonance (SSR) mitigation device, static blocking filter (SBF). This paper, with the test of the SBF device in the Tuoketuo project as the background, presents a comprehensive analysis to the nature of the system instability. The instability behavior...
There are many examples of antennas with exemplary bandwidth performance for their size that are characterized as having multiple impedance resonances within their operating bandwidth are presented in this paper. While the relationship between bandwidth and Q-factor is well defined for single resonance antennas, the relationship is more complex for multi-resonant antennas, and the degree of optimality...
This work is a continuation of an earlier study on drive level dependence (DLD), wherein the resistance of a thickness-shear crystal changes at low drive levels as the drive level changes. The earlier work used a 2-D Finite Element Analysis (FEA) to show that a surface irregularity, such as an attached particle, causes rotational imbalance in the motion of a contoured thickness-shear crystal, which...
A numerical eigenmode solver is used to analyze the behavior of two-, four-, and six-arm small multielement spherical antennas. The resonant frequency and radiation Q-factor of the natural modes of the shorted antenna structure are determined from eigenmode simulations using perfectly matched layer outer boundaries. The radiation resistance of each eigenmode at resonance is determined using a multiarm...
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