Search results

To investigate the possible application of carbon nanotubes (CNTs) as interconnects and antennas.

An electromagnetic macroscopic modelling of CNT is derived. The conduction electrons of the nanotube are considered as a 2D fluid moving on the surface representing the positive ion lattice. The linearized Euler's equation describing the fluid motion is used as a macroscopic constitutive relationship to be coupled to Maxwell's equation. A surface integral formulation coupled to the fluid model is solved numerically using a finite element method. For peculiar configurations, transmission line‐like parameters of CNTs are derived.

Single wall CNT interconnects, due to the high resistance and characteristic impedance with respect to ideally scaled silicon technology, should be used in arrays and bundles.

Only single wall CNTs are considered.

The paper present a novel approach to CNTs and provides a comparison among the behaviour of CNTs with respect to ideally‐scaled silicon technology.

To apply two different integral formulations of full‐Maxwell's equations to the numerical study of interconnects in a low‐frequency range and compare the results.

The first approach consists of a surface formulation of the full‐Maxwell's equations in terms of potentials, giving rise to a surface electric field integral equation. The equation, given in a weak form, is solved by using a finite element technique. The solenoidal and non‐solenoidal components of the electric current density are separated using the null‐pinv decomposition to avoid the low‐frequency breakdown. The second model is an extension of partial element equivalent circuit technique to unstructured meshes allowing the use of triangular meshes. Two systems of meshes tied by duality relations are defined on multiconductor systems. The key point in the definition of the equivalent network is to associate the pair primal edge/dual face to a circuit branch. Solution of the resulting electrical network is performed by a modified nodal analysis method and regularization of the outcoming matrix is accomplished by standard techniques based on the addition of suitable resistors.

Both the formulation have a regular behaviour at very low frequency. This is automatically achieved in the first approach by using the null‐pinv decomposition.

Surface sources of fields.

Two different integral formulations of full‐Maxwell's equations for the numerical study of interconnects are compared in terms of low‐frequency behaviour.

To study optical resonances in metallic nanoparticles.

The metallic nanoparticle is modeled as a dielectric body dispersive in frequency with assigned dielectric constant. The electric field is expressed as function of the charge distribution through an integral formulation. By imposing the boundary conditions on the nanoparticle surface, the equations for the induced charge in the nanoparticle is obtained. The numerical solution of such equations allows to treat arbitrary geometries and to estimate the effects of deviations from ideality on the resonance values.

Plasmon resonances in metallic nanoparticles can be safely studied with an electro‐quasistatic approximation. The resonance frequencies depend greatly on the details of the geometry of the nanoparticles.

The free‐space wavelength is supposed to be much greater than the largest characteristic dimension of the nanoparticles. Consequently, a electro‐quasistatic model is used to evaluate the distribution of the charges induced in the metallic nanoparticle.

Two methods are presented for the evaluation of the resonance frequencies starting from the numerical solution for a given geometry.

To provide a validation of a three‐dimensional (3D) macroscopic model for superconductors comparing numerical to experimental AC losses of a BSCCO‐2223 tape subject to an orthogonal magnetic field and a transport current.

We solve in 3D geometries the eddy current problem in presence of superconductors, represented by a power‐law characteristic rewritten into a variational form. An integral formulation of the magneto‐quasistatic Maxwell's equations is used. The solution of the problem is found by an unconstrained minimization of a suitable functional. The numerical results on AC losses computation are compared to experimental data.

The agreement between numerical and experimental data is good in a wide range of currents and magnetic fields.

The magnetic field is assumed to be orthogonal to the tape. Different incidence angles should be taken into account.

It is possible to extend the range of validity of the engineering formulae for AC losses used in the work.

The paper provides a validation of a numerical code against experimental results: this is always challenging in the field of applied superconductivity.