Richard W. Ziolkowski

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—A metamaterial paradigm for achieving an efficient, electrically small antenna is introduced. Spherical shells of homogenous , isotropic negative permittivity (ENG) material are designed to create electrically small resonant systems for several antennas: an infinitesimal electric dipole, a very short center-fed cylindrical electric dipole, and a very short(More)
—The effect of surrounding an electrically small dipole antenna with a shell of double negative (DNG) material (0 and 0) has been investigated both analytically and numerically. The problem of an infinitesimal electric dipole embedded in a homogeneous DNG medium is treated; its analytical solution shows that this electrically small antenna acts inductively(More)
—A planar Microwave Band Gap (MBG) cavity res-onator filter that is completely compatible with current commercial printed circuit board (PCB) fabrication techniques has been designed, fabricated and tested. This filter provides a 1.33% band-width passband response at 10.67 GHz with a corresponding insertion loss of 2.17 dB. Design considerations and(More)
The extension of the conventional finite-difference time-domain solution of the full vector Maxwell equations to modeling femtosecond optical-pulse propagation in a nonlinear Kerr medium that exhibits a finite response time is presented. Numerical results are given for nonlinear self-focusing in two space dimensions and time; the technique can be(More)
It is demonstrated that an approximation to the focus-wave-mode field can be generated from a dynamic Gaussian aperture. A source of this type is characterized by the time variation of its effective radius. The performance of such an aperture is studied in detail; it is demonstrated that the dynamic aperture shows a great enhancement over the corresponding(More)
We extend to more than one spatial dimension the semiclassical full-wave vector Maxwell-Bloch equations for the purpose of achieving an adequate and rigorous description of ultrashort pulse propagation in optical waveguides containing resonant nonlinearities. Our considerations are based on the generalized pseudospin formalism introduced by Hioe and Eberly(More)
—A reconfigurable planar electromagnetic bandgap (EBG) cavity resonator has been designed, fabricated, and tested. The resonator, based on a microstrip-coupled cavity constructed with periodic metallic post side walls, resonates at 10.60 GHz or 8.63 GHz, depending on the state of two rows of switchable post elements. Fabricated on 0.031 " 5880 Duroid, the(More)
—Planar two-dimensional (2D) and volumetric three-dimensional (3D) metamaterial-inspired efficient electrically-small antennas that are easy to design; are easy and inexpensive to build; and are easy to test; are reported, i.e., the EZ antenna systems. The proposed 2D and 3D electrical-and magnetic-based EZ antennas are shown to be naturally matched to a 50(More)
—A model of an idealized radiating system composed of an electrically small electric dipole antenna enclosed in an electrically small multilayered metamaterial shell system is developed analytically. The far-field radiation characteristics of this system are optimized using a GA-MATLAB based hybrid optimization model. The optimized-analytical model is(More)