Browsing by Subject "Split ring"

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Open Access
Designing materials with desired electromagnetic properties
(Wiley, 2006) Bulu, I.; Cağlayan, H.; Özbay, Ekmel
In this work, we suggest and demonstrate a robust method to tune the plasma frequencies of wire mediums. The method we suggest involves the use of two or more wire arrangements in the unit cell. By incorporating the method we suggested it is possible to tune the plasma frequencies of wire mediums effectively by use of lower metal densities. In addition, we study the effective permittivities and permeabilities of labyrinth based metamaterials. Our results show that the effective permeability of the labyrinth based metamaterial medium is negative above a certain frequency. The results of the effective permittivity calculations for the labyrinth based metamaterial medium reveal that the labyrinth structure exhibits a strong dielectric response near the magnetic resonance frequency. Finally, we design labyrinth based left-handed mediums that have several desired properties such as simultaneous μ, ε = -1 and μ, ε = 0. © 2006 Wiley Periodicals, Inc.
Open Access
Reconfigurable nested ring-split ring transmitarray unit cell employing the element rotation method by microfluidics
(Institute of Electrical and Electronics Engineers, 2015) Erdil, E.; Topalli, K.; Esmaeilzad, N. S.; Zorlu, O.; Kulah, H.; Aydin, C. O.
A continuously tunable, circularly polarized X-band microfluidic transmitarray unit cell employing the element rotation method is designed and fabricated. The unit cell comprises a double layer nested ring-split ring structure realized as microfluidic channels embedded in Polydimethylsiloxane (PDMS) using soft lithography techniques. Conductive regions of the rings are formed by injecting a liquid metal (an alloy of Ga, In, and Sn), whereas the split region is air. Movement of the liquid metal together with the split around the ring provides 360° linear phase shift range in the transmitted field through the unit cell. A circularly polarized unit cell is designed to operate at 8.8 GHz, satisfying the necessary phase shifting conditions provided by the element rotation method. Unit cell prototypes are fabricated and the proposed concept is verified by the measurements using waveguide simulator method, within the frequency range of 8-10 GHz. The agreement between the simulation and measurement results is satisfactory, illustrating the viability of the approach to be used in reconfigurable antennas and antenna arrays.