Abdul-Kadir Hamid

Axially Slotted Antenna on a Circular or Elliptic Cylinder Coated with Metamaterials

The radiation properties of an axially slotted circular or elliptical antenna coated with metamaterials are investigated. The fields inside and outside the dielectric coating are expressed in terms of Mathieu functions. The boundary conditions at various surfaces are enforced to obtain the unknown field expansion coefficients. Numerical results are presented graphically for the radiation pattern, aperture conductance and antenna gain for the TM case. It was found that slotted antenna coated with metamaterials has more directive beam with lower sidelobes compared to coated with conventional dielectric material.

SCATTERING BY A PERFECT ELECTROMAGNETIC CONDUCTING ELLIPTIC CYLINDER

An exact analytic solution is presented to the problem of scattering of a plane wave from a perfect electromagnetic conducting (PEMC) elliptic cylinder, using the method of separation of variables. The formulation is carried out by expanding the incident as well as the scattered electromagnetic flelds in terms of appropriate angular and radial Mathieu functions and a set of expansion coe-cients. The incident fleld expansion coe-cients are known, but the scattered fleld expansion coe-cients are unknown. Imposing the boundary conditions at the surface of the elliptic cylinder leads to the determination of the unknown expansion coe-cients in closed form. Results are presented as normalized scattering widths for elliptic cylinders of difierent sizes and PEMC admittances, to show the efiects of these on scattering.

Scattering of a Plane Wave by a Homogeneous Anisotropic Elliptic Cylinder

A formal series solution to the problem of scattering of a normally incident plane wave from an infinite homogeneous anisotropic elliptic cylinder is presented. The formulation of the problem is accomplished by assuming that the permittivity and the permeability tensors of the anisotropic material referred to the elliptic cylindrical coordinate axes are mainly biaxial and diagonal, and expanding each field associated with the problem in terms of a series of suitable Mathieu functions and expansion coefficients. The incident field expansion coefficients are known, but those associated with the scattered and transmitted fields are unknown. The unknown expansion coefficients are obtained by imposing appropriate boundary conditions at the surface of the anisotropic cylinder. Numerical results are presented as normalized bistatic and backscattering widths for elliptic cylinders of different sizes and permeabilities to show the effects of the material anisotropy on scattering.

TE scattering by a perfect electromagnetic conducting semi-elliptic-cylindrical boss on a perfectly conducting plane

An exact analytic solution is presented to the problem of scattering of a plane wave by a perfect electromagnetic conducting semi-elliptic-cylindrical boss located on an infinite perfectly conducting ground plane. The problem is formulated by expressing the incident, reflected, as well as the scattered electromagnetic fields in terms of appropriate angular and radial Mathieu functions and three sets of expansion coefficients. The coefficients associated with the incident and reflected field expansions are known, but those associated with the scattered field expansions are unknown. The unknown expansion coefficients can be determined analytically, by imposing appropriate boundary conditions at the surface of the associated perfect electromagnetic conducting elliptic cylinder. Results are presented as normalized scattering widths for semi-elliptic-cylindrical bosses of different sizes and admittances, to show the effects of these on scattering.

Modeling and optimization of hybrid solar-diesel-battery power system

this paper presents results on the simulation, modeling and optimization of an off grid hybrid solar PV/diesel/battery/inverter power system for residential application. The principal objective is to design a standalone renewable energy system to meet the desired electric load with high renewable fraction, low excess power and low cost of energy. Hourly simulations and optimization were performed to determine the performance and cost of the different hybrid power configurations. The results show that the solar PV/Diesel generator/battery/inverter power system offers the best performance compared to PV/Diesel generator/inverter; Diesel generator/battery/inverter and Diesel generator alone. From the total energy produced from the hybrid system, 87.6 % is used to meet all the AC load, 7.8 % is the excess electricity and 4.6 % are the system losses in both the battery and inverter. The proposed hybrid power system is sustainable, economically viable and environmentally friendly: high renewable fraction (53.25%), low excess power (7.8%), low levelized cost of energy (0.286

Miniaturization of waveguide antenna using square/circular arrays of SRR

/kWh), and low carbon dioxide emissions (67756 kg CO2/year).

Scattering from a coated perfect electromagnetic conducting elliptic cylinder

A miniaturized opened ended rectangular waveguide antenna radiating below the cutoff frequency of the waveguide is investigated. Miniaturization of the waveguide is achieved by loading the antenna with electromagnetic metamaterial (MTM) consisting of Square Shaped Ring Resonators (SSRR) or Circular shaped Ring Resonators (CSRR). These metamaterials provide the waveguide the ability to support the propagation of the backward wave below the cutoff frequency. The investigated open waveguide radiator was designed and simulated using High Frequency Structure Simulator HFSStm commercial software. Comparing the former work of miniaturized waveguides, we were able to obtain miniaturized antenna with 44.5 % reduction.