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In this contribution a nanodevice based on Localized Surface Plasmon Resonance (LSPR) phenomenon for biological characterization operating in the Visible and Near Infrared frequency Regime is proposed. The device consists of coupled biconical nanoparticles deposited on a silica substrate. By using a very small inter-particle distance it is possible to obtain a strong near electric field enhancement at the resonant wavelength suitable for ultra-sensitive biosensing applications. Full-wave simulations confirm the possibility to use the device as an optical sensor to detect in a ultra-sensitive way different cholesterol concentrations of the lipid membrane. [ABSTRACT FROM AUTHOR]

In this paper, we propose the design of high sensitivity and selectivity metamaterial-based biosensors operating in the THz regime. The proposed sensors consist of planar array of resonant metallic structures, whose frequency response is modified through the variation of the surrounding dielectric environment. We consider different resonator geometries, such as the squared, circular, asymmetrical, and omega ones, and the analysis of the biosensors is conducted through proper equivalent quasi-static analytical circuit models. The metallic particles are assumed deposited on a glass substrate through proper titanium adhesion layers. Exploiting the proposed analytical model, which is verified through the comparison to full-wave numerical simulations, we study the biosensor resonance frequencies as a function of the geometric parameters of the individual inclusions. Finally, we optimize the structure in order to obtain high sensitivity and selectivity performances. The numerical results show that the proposed structures can be successfully applied as biosensors working in the THz region. [ABSTRACT FROM AUTHOR]

Here we present an innovative design of microstrip antennas for wide-band mobile communications. In order to obtain reduced back-radiation, while keeping the overall antenna dimensions suitably compact for practical terminals, the proposed radiators are backed by a reactive ground plane, constituted of a suitably designed pattern of metallic patches. Moreover, the operative bandwidth is increased with the use of a proximity coupling feed and the choice of a polygonal patch shape. Some numerical results are reported, obtained through a rigorous Method of Moment numerical tool, to show the effective improvement that this design may offer in the antenna performance for UMTS mobile communication systems. [ABSTRACT FROM AUTHOR]

In this paper, we derive some original asymptotic expressions to speed up the computation of the excitation vector in the Method of Moments (MoM) numerical analysis of probe-fed planar microstrip antennas. These proposed expressions may be applied to the full-wave analysis of patch antennas in the spectral domain using the asymptotic Greens dyad of the planar integrated structure. It is shown in particular how planar patch antennas fed by a coaxial probe may be efficiently analyzed using fast converging ID integrals to represent the MoM excitation vector, instead of employing the standard spectral bi-dimensional integrals. The numerical results underline the quick convergence of these new expressions and the consequent reduction of the computational time with respect to standard techniques. [ABSTRACT FROM AUTHOR]

A new set of entire domain basis functions has been recently proposed in the literature for analyzing microstrip antennas with convex polygonal patches through a Method of Moment (MoM) numerical procedure. These basis functions represent a complete set of orthogonal functions, but they do not take into account the singular behavior of the tangential component of the current density at the patch edges. This property indeed limits the efficiency and accuracy of the analysis and only some particular geometries can be well described. When more accurate analyses are needed, the singular behavior of the current should be considered and the introduction of new auxiliary basis functions to fix the current behavior at the patch edges is a mandatory task. The aim of this paper is to present a new set of edge basis functions, suitable for a MoM analysis of convex polygonal patch antennas, to be used in conjunction with the entire domain basis functions already presented by the authors in order to improve the overall accuracy of the method. Some examples showing the capabilities of the new functions are proposed. [ABSTRACT FROM AUTHOR]

Analyzes the radiation properties of rectangular patch antennas with inhomogeneous substrates. Characteristics of devices with inhomogeneous materials; Synthesis of inhomogeneous materials by metallic inclusions; Importance of inhomogeneous materials in microwave applications.