Modelling of composite right/left‐handed active multiconductor transmission lines (AMCTL) in time domain

Abstract

An explicit finite difference time domain method is proposed for modelling of composite right-/left-handed active multiconductor transmission lines in time domain. For the first time, the concept of active composite right-/left-handed transmission lines is considered in field effect transistor (FET) modelling. In this work, based on the distributed model, the FET is considered as an active multiconductor transmission line in the mm/wave frequency range. In this modelling technique, the FET is divided into 2 different parts, the active part, represents the intrinsic equivalent circuit of the transistor, while the passive part symbolizes the device electrodes. The finite-difference time-domain scheme is proposed for the analysis, and the results of this technique are compared with the ones obtained from simulations. Furthermore, the stability issue is investigated and the sufficient condition for stability is derived. 14 Also, a time-domain analysis of the CRLH TL has been already investigated using numerical methods by Gomez-Diaz et al. 15 Additionally, the idea of active CRLH TL has already been applied to some devices and circuits. 16,17 Modern communication system performance strongly depends on active elements, among which field effect transistors (FETs) are largely present. However, their behaviour in the millimetre-wave frequency range is still perfectible. Analysing transmission lines in the millimetre-wave range will result in some complicated problems such as radiation and unwanted coupling between circuit elements. Therefore, a full wave approach needs to be used when the size of the electrodes are proportional to the wavelength. 18 However, full-wave analysis are usually based on highly complicated numerical techniques that require huge CPU time and computational resources. 18-21In the proposed modelling technique, the FET is considered in the form of 3 active TLs. Based on this modelling procedure, the device will be split into an infinite number of sections. Each section is composed of 3 multiconductor transmission lines (referring to gate, drain, and source) in which each electrode is supposed to be composed of metamaterial and a traditional

Distributed-Model-Based Approach for Electrical and Thermal Analysis of High-Frequency GaN HEMTs

“…As the explicit scheme is conditionally stable, there is a limitation associated with the temporal step size in order to satisfy the Courant stability condition. This condition is explained as the smaller value of the numerical time step compared to the time that the wave needs to travel to the adjacent grid point [24]. For analyzing complicated systems, Δt must be extremely small to keep the resultant numerical error bounded and this process increases the computation time of the solution.…”

Multi-Variable Stress Balancing Wireless Method Based on the Status of the Machines in the Cloud Spaces by Neural Networks<strong><em> </em></strong>

“…The considered load could be the processor load, the used memory, network delay or load [2]. Recently, multi-variable methods have been studied extensively for their wide application in various industries such as robotics, IOT and multiconductor transmission lines [3][4][5][6][7][8][9]. It seems that neural network has no issue but one problem of neural networks could be having to fix the depth of the network during training that prior synthesis methods suffer from, one feasible solution according to Hassantabar et al is a synthesis methodology that can generate compact and accurate neural networks [10][11] There are different methods to solve this issue, Mohammadzadeh et al suggest particle swarm optimization method [12][13] or Afshar implements Population Balance Modeling (PBM) and Initial Development Method (IDM) [14][15] on the other hand Azarang et al describe about Laplacian-based and Nonfragile fuzzy method [16][17][18].…”

Time-domain analysis of a CRLH coupled-line coupler using the CN-FDTD method

“…The finite-difference time-domain (FDTD) method as a versatile and easy-to-implement technique is successfully applied to numerical solutions. Recently, the CRLH TL has been analyzed based on the leap-frog (LF) FDTD method [7, 24]. But the LF method is conditionally stable due to the Courant–Friedrichs–Lewy (CFL) constraint [25].…”