Narrow Results

It is believed that the substrate integrated waveguide (SIW) technology represents the emergent and the most favorable contender for the advancement of the antennas, filters and the other circuit elements operational in the region of microwave as well as the millimeter wave frequencies. SIW layouts offer the advantages of the cost-effective integration of traditional transmission lines and retain the benefits of the classical metallic waveguides, in particular high-quality factors, low losses and the large power handling capability with the self-sufficient electrical shielding. In this paper, a review of the fundamental and operational theory of the SIWs has been discussed and presented. Moreover, the challenges and design considerations in terms of microwave and millimeter filters, the different miniaturization techniques and the most important; its application and implementation for the next-generation 5G communications and beyond has been presented.

This study examines the holographic representation of the quantum theory of transmission lines, which play a crucial role in quantum computing and quantum information. By utilizing Yurke and Denker’s quantum circuit network theory within the framework of continuous Multi-scale Entanglement Renormalization Ansatz (cMERA) in AdS space, we analyze the quantization and interactions of transmission lines. The metric is revealed to be described by the inductance of the quantum circuit, which is AdS space in its 0-limit. These results provide new insights into handling and controlling complex phenomena in quantum circuits, potentially advancing the understanding of quantum computing and quantum communication.

Half-T RC ladder networks (LNs) are proven to be first-order models of transmission lines (TLs) and interconnections. In this paper, the determination of LNs electrical characteristics, in terms of internal electrical parameters and number of cells, has allowed to calculate, in an approximated but very accurate way, the time delay and cutoff frequency of open-ended RC LN. Numerical examples on real designs confirm the validity of the proposed method in terms of robustness and accuracy.

In this paper, a new approach based on the real frequency technique (RFT) has been proposed to solve broadband matching problems using cascaded unequal length transmission lines. At the end of the design process, optimum characteristic impedance and delay values of transmission lines are obtained. Two examples are given to illustrate the utilization of the proposed approach.

So far, wind loads on structures are almost exclusively evaluated by Extended Pressure Systems (EPS) cyclone models according to design codes. However, there is evidence that downburst wind fields, originating from thunderstorms (TSs) events, may have caused or contributed to the collapse of transmission line towers around the world. In this context, this work proposes a complete methodology to simulate a wind field from combined EPS (synoptic) and TS (nonsynoptic) storms. The proposed combined wind field model is applied to a real transmission line segment and the results are compared with those of the system subjected to the equivalent static loading method proposed in the IEC 60826/2003 code. The finite central differences explicit method is adopted for dynamic integration, taking into account nonlinearities. The assessment confirmed the localized and transient nature of the TS phenomenon. The results indicated that, for most of the elements analyzed, the equivalent static method for synoptic winds of IEC 60826/2003 resulted in a lower response than that obtained through the proposed combined model, which considers a TS carried by an EPS background wind. Thus, the proposed method to combine synoptic and nonsynoptic wind fields might be a useful tool to assist in the design of structures, such as transmission lines, which are susceptible to the effects of combined EPS and TS wind fields.

It is important to calculate the electric field at the surface of high voltage direct current power transmission lines, since it is this field which governs the onset of corona discharge and the power loss arising therefrom. A method is presented here to calculate the electric field based on an implementation of the boundary element method for conductors of strictly circular cross section. Given the circular geometry it is possible to resolve all integrals involved analytically. A Galerkin approach is adopted, giving the solution in the spatial frequency domain. That allows a controlled truncation of the system matrix by choice of which frequency components to keep. It transpires that the low frequency components are the most important ones. Two test cases are used to quantify the accuracy of the solution with respect to truncation and distance from the surface. It is found that the accuracy increases with distance from the surface, but for all distances can be controlled by choosing an appropriate level of truncation.

Currently, the methods of calculation limiting capacity of transmission line are lack of economy and security. In this paper, based on the theory of the power circles and the conservative utility function, the proposed model can calculate limiting transmission capacity and meeting the security status of running transmission lines. Furthermore, on the condition that transmission lines meet economic and security policy, this paper utilizes the fault probability model that was improved by the conservative utility function to calculate limiting transmission capacity. Through analyzing the result of a calculation example, the paper can improve transmission capacity of existing transmission lines, and has great significance for promoting the future of grid transmission capacity.

Currently, the application of phase-to-phase spacers can effectively prevent and control line faults caused by conductor galloping and is one of the most effective methods to prevent galloping of transmission lines. The installation layout scheme of phase-to-phase spacers directly affects the anti-galloping effect. Moreover, the common empirical formula can not accurately assess the anti-galloping effect of phase-to-phase spacers. In this paper, the nonlinear finite element method is employed to establish an accurate analysis model of phase-to-phase spacers for conductors. And the anti-galloping effects of phase-to-phase spacers installed in different ways are analyzed, with the aim of providing an effective method for the installation of phase-to-phase spacers used in practical transmission lines.