Effects of using different boundary conditions and computational domain dimensions on modeling and simulations of periodic metamaterial arrays in microwave frequencies

2013-07-01
Turkmen, Oznur
EKMEKÇİ, Evren
Sayan, Gönül
This article aims to demonstrate the effects of using different boundary conditions and different computational volume dimensions in numerical simulations of periodic metamaterial arrays. A double band metamaterial unit cell design will be utilized to show that use of different boundary conditions may result in simulation of dissimilar periodic array topologies with completely different electromagnetic responses. It will also be shown that dimensions of the computational volume may strongly affect the overall response of the metamaterial structure due to varying electromagnetic coupling between the array elements. (c) 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.
INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING

Suggestions

Impact of defected ground structures on the bandwidth of quarter wave impedance transformers and branch line hybrids
Polater, Ahmet Mert; Nesimoglu, Tayfun (Wiley, 2016-05-01)
In this article, impedance transformers and branch line hybrids are selected to demonstrate the impact of defected ground structures on the operational bandwidth of microwave circuits. Three different branch line hybrids are studied with simulations and laboratory measurements, these are; a standard branch line hybrid, one using tapered lines and another one using both tapered lines and DGS. Based on these results, an optimum design in terms of location, size and number of DGS was proposed to achieve the wi...
Non-destructive recognition of dielectric coated conducting objects by using WD type time-frequency transformation and PCA-based fusion
Sayan, Gönül (Wiley, 2013-07-01)
This article demonstrates the applications of a non-destructive electromagnetic target recognition method, called Wigner distribution-principal component analysis (WD-PCA) method, to dielectric coated conducting spheres. These spheres are chosen to be highly similar having the same overall size but slightly different permittivity and thickness values in coating layers. Four different classifiers are simulated by using the WD-PCA method for varying sizes of object libraries under different noise conditions. ...
Monte Carlo analysis of ridged waveguides with transformation media
Ozgun, Ozlem; Kuzuoğlu, Mustafa (Wiley, 2013-07-01)
A computational model is presented for Monte Carlo simulation of waveguides with ridges, by combining the principles of transformation electromagnetics and the finite methods (such as finite element or finite difference methods). The principle idea is to place a transformation medium around the ridge structure, so that a single and easy-to-generate mesh can be used for each realization of the Monte Carlo simulation. Hence, this approach leads to less computational resources. The technique is validated by me...
Transformation-based metamaterials to eliminate the staircasing error in the finite difference time domain method
Ozgun, Ozlem; Kuzuoğlu, Mustafa (Wiley, 2012-07-01)
A coordinate transformation technique is introduced for the finite difference time domain method to alleviate the effects of errors introduced by the staircasing approximation of curved geometries that do not conform to a Cartesian grid. An anisotropic metamaterial region, which is adapted to the Cartesian grid and designed by the coordinate transformation technique, is constructed around the curved boundary of the object, and the region occupied between the curved boundary and the inner boundary of the ani...
Minimization of Monotonically Levelable Higher Order MRF Energies via Graph Cuts
Karci, Mehmet Haydar; Demirekler, Mübeccel (Institute of Electrical and Electronics Engineers (IEEE), 2010-11-01)
A feature of minimizing images of submodular binary Markov random field (MRF) energies is introduced. Using this novel feature, the collection of minimizing images of levels of higher order, monotonically levelable multilabel MRF energies is shown to constitute a monotone collection. This implies that these minimizing binary images can be combined to give minimizing images of the multilabel MRF energies. Thanks to the graph cuts framework, the mentioned class of binary MRF energies is known to be minimized ...
Citation Formats
O. Turkmen, E. EKMEKÇİ, and G. Sayan, “Effects of using different boundary conditions and computational domain dimensions on modeling and simulations of periodic metamaterial arrays in microwave frequencies,” INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, pp. 459–465, 2013, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/35263.