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D.T. Kelley

Bio: D.T. Kelley is an academic researcher. The author has contributed to research in topic(s): Modal analysis & Boundary value problem. The author has an hindex of 1, co-authored 1 publication(s) receiving 11 citation(s).
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Journal ArticleDOI
Larry Epp1, Daniel J. Hoppe1, D.T. KelleyInstitutions (1)
Abstract: A TE/TM modal solution for a longitudinally corrugated rectangular waveguide is developed. These longitudinal corrugations can be used to excite a quasi-TEM wave and form a hard waveguide by correctly choosing the impedance at the guide wall. The correctly chosen impedance is referred to as the hard boundary condition. The modal solution developed here solves the problem of longitudinal corrugations filled with a dielectric material by first finding and solving the characteristic equation for a complete TE/TM modal set. It is shown that this TE/TM mode solution can be used to achieve the hard boundary condition resulting in the quasi-TEM wave in a hard waveguide for discrete values of corrugation depth. Beyond each of these depths, a mode becomes a surface wave. The theoretical mode set is amenable to the solution of problems using the mode-matching method. A combination of the mode-matching method and the TE/TM modal solution will allow the solution of larger problems.

11 citations

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Proceedings ArticleDOI
24 Oct 2020
TL;DR: A combination of P3HT: PCBM with parallel vertical LiF cylinders formulate the active material structure and the LiF is considered a suitable material for the vertical cylinders in the proposed structure.
Abstract: In this paper, we introduce active material for an organic solar cell with a modified composition. A combination of P3HT: PCBM with parallel vertical LiF cylinders formulate the active material structure. The collection efficiency in the active material reaches 92.2%. The operating wavelength where the maximum collection efficiency occurs is adjusted and matched with the wavelength where the maximum irradiance of the solar spectrum occurs. The absorption per unit volume of the new structure is 80.4 µm−3 while the blank structure is 75.07 µm−3. The net absorption magnitude for the required structure is 32.09. The LiF is considered a suitable material for the vertical cylinders in the proposed structure. At a depth of 95 nm and operating wavelength 500 nm, for TE mode, LiF has the highest insertion losses with 0.7 dB. However, ITO and ZnO possess 0.35 dB and 0.49 dB, respectively. For TM mode, LiF has the lowest insertion losses at the same depth with 0.7 dB, while ZnO possesses 0.49 dB. However, ITO performs the highest insertion losses at the same depth with 0.77 dB.

Journal ArticleDOI
Abstract: This article presents an efficient analysis method for a novel continuous transverse stub (CTS) antenna. As opposed to state-of-the-art CTS antenna designs, the proposed architecture achieves circular polarization using a single CTS array and without any polarization converter. The structure consists of long radiating slots/stubs fed by over-moded parallel-plate waveguides. More precisely, the transverse electromagnetic (TEM) mode and the first transverse electric (TE1) mode of the feeding waveguides are used to generate a circularly polarized field. The array is analyzed using a spectral mode-matching method. First, the active reflection coefficient of the infinite array is derived in closed form. A windowing approach is then adopted to compute the radiation patterns of finite-size arrays. Numerical results obtained with this method are in excellent agreement with full-wave simulations, carried out with a commercial software. The performance of this class of CTS antennas has been investigated using the developed model. It is theoretically demonstrated that the proposed array can be designed to attain an axial ratio (AR) lower than 3 dB over a 52.9% relative bandwidth at broadside. Furthermore, the active input reflection coefficient is lower than −10 dB over a 40.8% relative bandwidth, when the array steers its main beam at $\theta _{0}=45^\circ $ . This solution is an attractive candidate for next generation satellite communication terminals.

4 citations

Journal ArticleDOI
Abstract: The coupled transcendental equations describing cutoff frequencies of TE and TM modes are deduced for a rectangular waveguide with arbitrary wall impedance. In the case of TE modes, their generalization is made to a rectangular guiding structure, which possesses both distributed wall impedance and inhomogeneous dielectric loading. Effective impedance is obtained for imperfectly conducting surface incorporating periodic rectangular corrugations along the direction of mode propagation. Circular waveguide bounded by such corrugated surface and rectangular impedance waveguide are considered as numerical examples. For these waveguides, the computations performed to determine the cutoff frequencies of TE guiding modes are validated against the results of the perturbation theory and the finite-element method.

14 citations

Journal ArticleDOI
Malcolm Ng Mou Kehn1Institutions (1)
Abstract: The asymptotic corrugations boundary conditions (ACBCs) are used together with classical theory of vector potentials and an innovative combination of matrix systems to analyze rectangular waveguides having all four walls being longitudinally (axially) corrugated. One matrix system is composed of the ACBCs of two opposite walls, while the other comprises those of the other pair of corrugated walls. A transcendental characteristic equation is derived, from which the modal dispersion diagram can be obtained, for all three modal wave-tyoes: fast space, slow surface, and evanescent waves. From the formulation, analytical modal field functions in closed form are also acquired. Results of dispersion graphs and modal field distributions generated by this method are compared favorably with those obtained by a commercial full-wave solver.

5 citations

Proceedings ArticleDOI
14 May 2013
Abstract: In this paper, First the structure of a rectangular waveguide with a longitudinal slot is presented to show the quasi-TEM wave with uniform distribution in the waveguide width. This Quasi-TEM wave improves the aperture field illumination of the slot and enhances the efficiency in this kind of antennas. Finally, by simulation a slot antenna is excited by a quasi-TEM wave. The results indicate the high efficiency of this antenna.

2 citations


Author's H-index: 1

No. of papers from the Author in previous years