LOSSY TRANSMISSION LINES TERMINATED BY PARALLEL CONNECTED RLC-ELEMENTS WITHOUT THE HEAVISIDE’S CONDITION

The paper deals with analysis of propagation of transverse electromagnetic waves along lossy transmission lines terminated by a circuit consisting of parallel connected RLCelements. Using the Kirchhoff’s laws we derive boundary conditions and formulate the mixed problem for hyperbolic system describing the lossy transmission line. Without the Heaviside's condition, we cannot guarantee the distortionless propagation of waves and hence we cannot apply the known methods. That is why we apply a different method and obtain conditions for existence-uniqueness of generalized solution. We change variables and formulate a mixed problem for the hyperbolic system with respect to the new variables. The nonlinear characteristics of the RLC-elements generate nonlinearity in the equations of neutral type on the boundary. We propose an operator presentation of the mixed problem for transmission line system and by means of fixed point technique we prove existence-uniqueness of a generalized solution.

PurposeThis 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/approachAn 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.FindingsComparison 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/valueThis 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.

The reciprocity theorem of antenna is introduced in this paper in researching the coupling between the spatial electromagnetic wave and transmission line on PCB; the complex calculation of the scattering field is avoided. The coupling voltage of the loads is studied in this paper with spatial EM wave incidence upon a transmission line on PCB.

Monitoring of resin flow and cure with an electromagnetic wave transmission line using carbon fiber as conductive elements

This work derives exact expressions for the radiation from two conductors non‐isolated transverse electromagnetic (TEM) transmission lines of any small electric size cross‐section in free space. The cases of infinite, semi infinite and finite transmission lines are covered and it is shown that while an infinite transmission line does not radiate, there is a smooth transition between the radiation from a finite to a semi‐infinite transmission line. The present analysis is in the frequency domain and the authors consider transmission lines carrying any combination of forward and backward waves. The analytic results are validated by successful comparison with ANSYS commercial software simulation results, and successful comparisons with other published results.

This paper presents a multi-bandpass filter using the slit-top mushroom-like on two-layer of electromagnetic band gap (EBG) and transmission line structures. The proposed EBG filter will be utilized as diplexers. The characteristics of this diplexer have been studied by using CST software that was found that it can provide the very good performance. The maximum isolation and minimum insertion loss at the Rx-port when the diplexer operates in Tx-mode are around −40.22 dB and −1.38 dB, respectively. The maximum isolation and minimum insertion loss at the Tx-port in Rx-mode is around −38.42 dB and −0.85 dB, respectively. The bandwidth of Tx-mode and Rx-mode are in the range of 3.646 to 3.715 GHz and 3.141 to 3.214 GHz. This work is the feasibility study of the diplexer design by using EBG technology which can be modified to the other desired frequency bands.

This work presents a Ka-band two-way 3 dB Wilkinson power divider using synthetic quasi-transverse electromagnetic (TEM) transmission lines (TLs). The synthetic quasi-TEM TL, also called complementary-conducting-strip TL (CCS TL), is theoretically analyzed. The equivalent TL model, whose production is based on the extracted results, is applied to the power divider design. The prototype is fabricated by the standard 0.18 mum 1P6M CMOS technology, showing the circuit size of 210.0 mumtimes390.0 mum without contact pads. The measurement results, which match the 50 Omega system, reveal perfect agreements with those of the simulations. The comparison reveals the following characteristics. The divider exhibits an equal power-split with the insertion losses (S21 and S31) of 3.65 dB. The return losses (S11, S22 and S33) of the prototype are higher than 10.0 dB from 30.0 to 40.0 GHz.

In this study, a novel quasi-transverse electromagnetic (TEM) transmission line (TL) on a single-layer substrate is presented. The proposed structure comprises bilateral metalised vias and two longitudinal slots on the top and bottom plates, respectively. This two-conductor TL separated by the two slots allows the quasi-TEM mode and guarantees high isolation due to the vias which constrain the electromagnetic field. Additionally, the proposed structure provides a remarkable high range of the characteristic impedance, enabling a more flexible design. Furthermore, an empirical analytical formula is derived to calculate the characteristic impedance of the proposed TL adopting conformal mapping, and modified by a polynomial fraction. The transitions to the double-sided parallel-strip line and the microstrip line are proposed with which the propagation constant of this TL is extracted. The comparisons of the far-end couplings of several types of microwave TLs have been provided by the simulation and measurement to verify the isolation property of the proposed TL. Finally, the proposed TL is applied to the T-junction wideband power divider design to demonstrate its practicability. A prototype is fabricated and measured with a wide operating bandwidth from 6.8 to 17.6 GHz.

In this chapter, we discuss the transmission line theory and its application to the problem of external electromagnetic fi eld coupling to transmission lines. After a short discussion on the underlying assumptions of the transmission line theory, we start with the derivation of fision line coupling equations for the case of a single wire line above a perfectly conducting ground. We also describe three seemingly different but completely equivalent approaches that have been proposed to describe the coupling of electromagnetic fito transmission lines. The derived equations are extended to deal with the presence of losses and multiple conductors. The time-domain representation of fision line coupling equations, which allows a straightforward treatment of non-linear phenomena as well as the variation in the line topology, is also described. Finally, solution methods in frequency domain and time domain are presented. 1 Transmission line approximation The problem of an external electromagnetic fi eld coupling to an overhead line can be solved using a number of approaches. One such approach makes use of antenna theory, a general methodology based on Maxwell’s equations [1]. Different methods based on this approach generally use the thin-wire approximation, in which the wire’s cross section is assumed to be much smaller than the minimum signifi cant wavelength. When electrically long lines are involved, however, the antenna theory approach requires prohibitively long computational times and high computer resources. On the

An electromagnetic field and artificial intelligence-based transmission line protection system for smart grid is proposed in this paper. Bayesian regularization neural network is used as an intelligence technique. Instead of conventional current transformers, the use of magnetic field sensors for monitoring the current in transmission lines is proposed. A mathematical model of the magnetic field due to the current in transmission line is developed by considering two positions of the magnetic field sensors. The developed model is simulated for extensive scenarios. Line to ground, line to line, double line to ground and three-phase faults are created. The fault current values are transformed into magnetic field values and given to the dyadic analysis filter bank for feature extraction process. The extracted features are given as an input to the neural network for the training. The Bayesian regularization algorithm is used as a training algorithm. The performance of the proposed system is compared with other algorithms. It shows that the proposed system with Bayesian regularization have 96.11% of accuracy with the combination of different faults. The results obtained show that the proposed system outperforms the existing approaches.

Applied Electromagnetics and Electromagnetic Compatibility

In this paper, the wave propagation of a graphene based conductor (GBC) transmission line (TL) and its comparison with a copper TL on a conformal surface is presented. An investigation of the coupling between parallel GBC TLs and copper TLs is also summarized in this work. A 150 mm long TL was initially manufactured on a flexible substrate and the wave propagation characteristics were investigated on a conformal surface. Then, a microstrip copper TL was manufactured and the wave propagation on a conformal surface was compared with the GBC TL. Also, prototypes with various combinations of two parallel TLs (GBC — GBC TLs, GBC TL — Copper TLs, etc.) were manufactured and studied for comparison. It was shown that the wave propagation properties of a given GBC TL on a conformal surface were similar to that of a copper TL over the frequency band of 100 KHz to 8.5 GHz. Moreover, results of the near- and far-end coupling showed that the GBC TLs can be used as an alternative to copper TLs as they can provide better coupling on a conformal surface.

Design of high-speed, high-performance electronic circuits requires simulation of transients in networks that include multiple, coupled lossy transmission lines. A widely used circuit simulator, SPICE, does not have facilities for simulation of multiconductor transmission lines. Recently a modification to SPICE3 to include multi-conductor lossless lines was reported. In many situations line losses must be included in the model and networks with lossy transmission simulated. In general simulation of lossy transmission lines is complex and computationally very intensive. The situation is simpler when D-C losses are considered. A recent study concluded that D-C losses provide an adequate modeling of signal transmission in many practical situations. This paper describes the implementation of multi-conductor, coupled lines with D-C losses in SPICE3e2. This implementation ties SPICE transient analysis with a special algorithm for the analysis of a transmission line and is more efficient than another approach based an the concept of a transmission line subcircuit. Internal tests of the new program, LSPICE3, were successfully performed and now this program is available to SPICE3 users. >

A new synthetic quasi-TEM (transverse electromagnetic) transmission line (TL) is presented for achieving higher characteristic impedance (Z/sub c/). The proposed synthetic TL consists of a 2D array made of complementary-conducting strips (CCS) unit cell, which permits tuning for desired propagation characteristics of the transmission line under synthesis. Based on the particular case study, both theoretical and measured results agree excellently for the comparative studies for the proposed synthetic TL and the conventional microstrip. The Z/sub c/ of a synthetic TL is 130% higher than that of a wide microstrip. Furthermore, the extracted slow-wave-factor is 17.7% higher than the physical limit of microstrip.

A phenomenological loss equivalence method is proposed to calculate the conductor losses of planar quasi-TEM (transverse electromagnetic) transmission lines over a wide frequency range. In this method the conductor losses can be readily calculated from a single strip equivalent to the original transmission lines. The calculated results for microstrip line are in good agreement over a broad bandwidth with those calculated using the finite-element method. Because of its simplicity, this method should be very useful for computer-aided design of monolithic microwave circuits. In addition, this method can also be applied to very thin and narrow superconductive lines using the complex conductivity based on the two-fluid model. >