Richard W. Ziolkowski

Aycan Erentok10
Amr M Shaarawi6
J A Nielsen4
M H Tanielian4
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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)
—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)
—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)
—The design, fabrication and measurement of a volu-metric metamaterial realization of an artificial magnetic conductor (AMC) is presented. In contrast to most current realizations of AMCs, such as the mushroom and the uniplanar compact photonic bandgap surfaces, the present design has no perfect electric conductor ground plane. The perfect magnetic(More)
  • Aycan Erentok, Richard W Ziolkowski, J A Nielsen, R B Greegor, C G Parazzoli, M H Tanielian +5 others
  • 2007
A lumped element-based negative index metamaterial ͑NIM͒ was designed, fabricated, and tested for operation at 400 MHz in the ultrahigh frequency ͑UHF͒ band. At 400 MHz the measured real part of the index of refraction of this NIM was n real = −3.11 with a loss that was less than 1 dB/ cm using unit cells whose overall size d was ␭ / d ϳ 75. The NIM(More)
— This paper studies the feasibility of enhancing the spatial resolution of multi-look Multispectral Thermal Imager (MTI) imagery using an iterative resolution enhancement algorithm known as Projection Onto Convex Sets (POCS). A multi-angle satellite image modeling tool is implemented, and simulated multi-look MTI imagery is formed to test the resolution(More)
A population coded algorithm, built on established models of motion processing in the primate visual system, computes the time-to-collision of a mobile robot to real-world environmental objects from video imagery. A set of four transformations starts with motion energy, a spatiotemporal frequency based computation of motion features. The following(More)
Photonic bandgap (PBG) structures constructed from lossy, dispersive dielectric and metallic materials are characterized in terms of their reflection and transmission properties. Particular emphasis is given to PBG structures with defects. These PBG structures are modeled analytically with an ABCD matrix method for their single-frequency response. They also(More)