arXiv subjects

C. R. Simovski

Publications and source records attributed to C. R. Simovski.

22 records · Page 2Linked to original sources

arXiv2004

The influence of complex material coverings on the bandwidth of antennas

The influence of material coverings on the antenna bandwidth is investigated for antennas formed by thin electric or magnetic line sources. It is shown that uniform thin layers of arbitrary passive materials (including Veselago, left-handed, or double-negative materials) cannot help to overcome the bandwidth limitations imposed by the amount of energy stored in the antenna reactive field. Alternative possibilities offered by complex composite materials in the antenna design are identified.

physics.class-ph↗

arXiv2003

Toward creating isotropic microwave composites with negative refraction

The properties of artificial isotropic microwave composites which would possess simultaneously negative permittivity and permeability are studied theoretically. Four kinds of composites are considered. Two of them concern media with split-ring resonator particles with different particle arrangements. The other two are realized with Omega particles. An analytical antenna model of the electromagnetic behavior of a split-ring resonator (SRR) is suggested and verified by numerical simulations. Next, material parameters of composite media made with SRR or Omega particles are calculated. It is shown that the Omega-composites are more prospective for obtaining negative real values of permittivity and permeability than the split-ring resonators.

cond-mat.mtrl-sci↗

arXiv2002

Strong spatial dispersion in wire media in the very large wavelength limit

It is found that there exist composite media that exhibit strong spatial dispersion even in the very large wavelength limit. This follows from the study of lattices of ideally conducting parallel thin wires (wire media). In fact, our analysis reveals that the description of this medium by means of a local dispersive uniaxial dielectric tensor is not complete, leading to unphysical results for the propagation of electromagnetic waves at any frequencies. Since non--local constitutive relations have been usually considered in the past as a second order approximation, meaningful in the short wavelength limit, the aforementioned result presents a relevant theoretical interest. In addition, since such wire media have been recently used as a constituent of some discrete artificial media (or metamaterials), the reported results open the question of the relevance of the spatial dispersion in the characterization of these artificial media.

cond-mat.mtrl-sci↗

arXiv2002

Backward wave region and negative material parameters of a structure formed by lattices of wires and split-ring resonators

A structure formed by combined lattices of infinitely long wires and split-ring resonators is studied. A dispersion equation is derived and then used to calculate the effective permittivity and permeability in the frequency band where the lattice can be homogenized. The backward wave region in which both the effective permittivity and permeability are negative is analyzed. Some open and controversial questions are discussed. It is shown that previous experimental results confirming the existence of backward waves in such a structure can be in deed explained in terms of negative material parameters. However, these parameters are not quasi-static and thus the known analytical formulas for the effective material parameters of this structure, which have been widely used and discussed in the literature, were not correct, and it was the reason of some objections to the authors of that experiment.

cond-mat.mtrl-sci↗