The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Many problems in nature and engineering are multiscale. Thus, for adequately representing structure geometrical details, one has to use small cell sizes which impose small time-step values. In addition, if the mesh is irregular but structured it might lead to exhaustive computer expenditure and higher dispersion. The alternate approach is to use block-meshing techniques which allow fine discretization...
With the advancement of technology, modern equipment involves new functionalities that require complex media (e.g., anisotropic dispersive media such as ferrite, lossy dielectrics, or graphene) for a variety of applications. This imposes the necessity to extend simulation techniques capable of solving Maxwell’s equations in such media. However, as far as discrete time-domain models are concerned,...
Starting with a frequency domain analysis of the ground impedance between two points on a solid ground plane of a printed circuit board, closed formulae to calculate the ground impedance in frequency domain is presented. The approach which takes into account the skin-effect and striction effect in frequency domain is extended to calculate the voltage difference between two points on the ground plane...
This paper explores the effect of increasing number of receivers to evaluate the geographic location of the High Frequency (HF) transmitters for distances in the radius of 2000 km. In the case of HF propagation over long distances, signals propagate using skywaves and are reflected back to the earth from the ionosphere. The Quasi-Parabolic (QP) model of the ionosphere provides analytic equations for...
The interaction between electromagnetic waves and complex media and its consequences on other physical phenomena such as hyperthermia is a crucial issue for various types of applications. To name a few, electromagnetic compatibility, microwave ovens design, medical applications, and the design of electromagnetic devices and circuits that include lossy media. In this article, we present a full-wave...
Ferrite material plays an important role in modern microwave components such as isolator, circulator and phase shifter. Also, they provide some agility to externally tune devices by adjusting a DC magnetic field which modifies the constitutive parameters. However, ferrite medium is complex and elaborated modelling procedures are required to carry out full-wave electromagnetic simulation. A general...
Among the techniques widely used in CEM (Computational Electromagnetics), the FDTD method (Finite-Difference Time Domain) is one of the most demanding in computational resources. Despite the computing power available today on a personal computer, industry demands the analysis of large and complex models to be used in several electromagnetic applications. The algorithm of the FDTD method is based on...
Inherent to time-domain method that use space-time discretization, the model dispersion produces field propagation velocity error. In methods such as finite-differences or TLM in time domain, it is customary to choose a maximum mesh size of one tenth of the minimum operating wavelength. If this criterion is easily applicable for normal ordinary media, it is more ambiguous to give interpretation of...
Like other so-called volumic methods, the TLM requires artificial boundaries when simulations of open problems are performed. There are two cases for which artificial boundaries are needed: when structures under investigation are surrounded by unbounded space or when discontinuity characterization needs matched loads. These artificial boundaries enforce conditions commonly named absorbing boundary...
The Transmission Line Matrix (TLM) method is a well-known numerical time-domain technique which has been widely used for solving electromagnetic field problems. Axially symmetric structures are frequently encountered in microwave engineering. For this purpose, a first memory-saving TLM algorithm was developed in the particular case of uniform guiding structures [1]. Based on the classical Symmetrical...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.