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In this work, we have investigated the mechanism of performance enhancement of a dipole antenna located above a ground plane, and covered by a dielectric EBG superstrate. We show that the maximum enhancement in the received power can be up to 9.3 dB for the composite. We have gained considerable insight into the mechanism of directivity enhancement that should help us with future designs.
In this paper we determine the weights of the spatial harmonics in a periodic structure, with quasi-periodicity along the propagation direction, by detailed analysis of the fields inside the unit-cells. We use both the Pronypsilas method and Fourier transform to extract the spectrum of the fields inside the unit cells along the propagation direction and compare the results obtained by each method...
In this paper we study the antenna/woodpile electronic bandgap (EBG) composite by using the finite difference time domain (FDTD) Method. The near-field as well as far-field performance are examined at different frequencies with a view to realizing enhanced directivity. In addition, the structure is modeled and simulated under plane wave illumination and the scattered fields are computed to gain an...
This paper presents a novel and systematic approach for enhancing the directivity of an antenna/EBG composite, comprising of a microstrip patch antenna covered by an FSS superstrate. The method is based on the initial simulation of the composite operating in the receive mode, mapping the field distribution in the Fabry-Perot type cavity region formed by the superstrate and the ground plane. Additionally,...
In this work we present a novel approach to constructing the layered medium Green's function using the BOR (body of revolution) version of the FDTD, which has several desirable attributes: (a) It poses no difficulty when handling n-layer problems, even when n is large; (b) it is easy to analyze lossy layers, including RAM materials; (c) the location of the observation point can be arbitrary in terms...
A new bandpass frequency selective surfaces (FSS) is designed and the composite system (patch antenna covered by an FSS) is analyzed using the finite difference time domain (FDTD) method. Far-field patterns of the patch antenna, with and without FSS radomes, are obtained and compared with each other. The feed is modeled by using a coaxial line extension, which enables us to compute the return loss...
In this paper we use the spectral finite difference time domain (SFDTD) to analyze patch-type frequency selective surface illuminated by an oblique angle of incidence. The results are compared with those obtained by using the method of moments (MoM) and the split-field FDTD technique
In this paper, we present a technique to calculate near and far-field phase center of axially-symmetric feeds using finite difference time domain method of bodies of revolution. To illustrate the application of the proposed approach, several feeds are analyzed. The numerical results show good agreement with those obtained by using analytical expressions
In this paper, we investigate a large dual-reflector (Cassegrain) antenna system, typically used as a ground station antenna in the space communication link. The study includes the blockage effects of the subreflector and the struts on the radiation performance of the antenna, as well as the estimation of the combination to the pattern degradation due to the panel gaps. The large electrical dimension...
AbstractThe murine monoclonal antibody YB5.B8 (CD117) identifies a transmembrane tyrosine kinase receptor encoded by the human c-kit proto-oncogene. In this study we investigated the expression of c-kit on different types of acute leukemia to determine the degree of specificity and sensitivity of this marker for the myeloid and lymphoid lineages. C-kit was positive in over half of the 115 cases of...
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