Modeling of magnetostatic resonances in small-size metamaterials

This work studies the resonant behavior of nanoscale magnetic materials. This behavior, henceforth referred to as magnetostatic resonance, occurs at frequencies where the permeability is negative and the particle is much smaller than the wavelength. A surface integral equation is formulated on the boundary of the particle to calculate the resonance frequencies and modes. Unique physical properties of these resonances such as scale invariance of resonance frequency and orthogonality properties of resonant modes are studied. A numerical technique is presented to calculate the magnetostatic resonance frequencies of an arbitrary shape. Possible applications of these phenomena are outlined.     

<Emphasis Type="Italic">n</Emphasis>th order Rose curve as a generic candidate for RF artificial magnetic material

Recent work demonstrated that the permeability and magnetic loss tangent of artificial magnetic material inclusions can be represented simply in terms of the circumference and area of the inclusion. While such a representation makes direct use of the inclusion’s circuit model, the fact that the magnetic properties can be described in terms of the perimeter and area of the inclusion facilitates designing inclusions that achieve specific constraints without the need for intensive full-wave trial and error simulations. Because of such flexibility, we propose a new set of generic curves described as nth order Rose curves to be candidates for AMMs. In fact, the new curves not only provide significant design flexibility, but provide features not present in traditional topologies, most pronouncedly a wider band over which negative permeability is achieved with low dispersion.     

Analytical formulation of the radiation field of printed antennas in the presence of artificial magnetic superstrates

In this paper, the cavity model of a microstrip patch antenna in conjunction with the reciprocity theorem is used to develop a fast analytical solution for the radiation field of a microstrip patch antenna loaded with a novel artificial magnetic superstrate and to investigate the effect of the engineered superstrate layer on the directivity and radiation pattern of the printed patch antenna.     

On the Finite Screw Cylindroid Represented as a 2-system of Screws

The problem of displacing a line with a definite point on it from one spatial position to another is studied by utilizing the concept of screw matrix. It is known that all the available finite twists (screws) associated with this displacement form a ruled surface, the so-called finite screw cylindroid. If the definition of the pitch given by Parkin is used, then the finite screw cylindroid can be regarded as a 2-system of screws. This brings to one's mind the question as to whether there exist different appropriate measures for pitch other than Parkin's under which all the available finite twists form a 2-system. This question is answered in this paper. By deriving a general expression of the pitch for these available finite twists under the said condition, it is shown that Parkin's pitch plus an arbitrary constant is the only possible measure of pitch under which the finite screw cylindroid represents a 2-system of screws. However, since adding a constant to the pitches of all screws of any 2-system still gives a 2-system, constant term may be omitted. It is also shown that the determined 2-system of screws can be described as a linear combination of two special basis screws which are called in this paper the = 0 and the = screws.     

Near-field subsurface detection using metamaterial inspired probes

Recently, it was shown that single negative media can significantly enhance the sensitivity of near-field probes. Inspired by this recent finding, a new near-field probe is proposed for noninvasive subsurface detection. The new probe uses a single split ring resonator (SRR) instead of a periodic arrangement of SRRs for negative material realization. Experimental tests were conducted to detect the presence of cracks on aluminum plates, the presence of small aluminum blocks located behind a layer of ground chicken (lossy medium), and the presence of a small aluminum block submerged in sodium chloride solution (lossy medium) with a salinity of 1%. Preliminary results show that the proposed near-field probe enables detection of electrically small targets buried in lossy media.