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Design of planar rectangular spiral antennas for the wireless vehicle battery charging system
(2013-12-01)
Phaebua, K.
;
Torrungrueng, D.
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Phongcharoenphanich, C.
A design of planar rectangular spiral antennas for the wireless vehicle battery charging system operating at 13.56 MHz is presented in this paper. The proposed antennas are designed with low-cost, low-complexity and low-profile constraints. The study is performed by analyzing the power transmission efficiency of the spiral antennas via scattering parameters and associated reflection coefficients. Moreover, the misalignment between the transmitting and receiving antennas and effects of a car structure on the power transmission efficiency are investigated. It is found that the misalignment and the car structure strongly affect the power transmission efficiency. © 2013 IEEE.
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A uniform geometrical theory of diffraction for radiation and coupling associated with antennas on a smooth convex impedance surface
(2012-11-07)
Pathak, P. H.
;
Phaebua, K.
Uniform Geometrical Theory of Diffraction (UTD) ray solutions are developed for describing the radiation and mutual coupling that is associated with antennas on smooth convex metallic surfaces with a thin material coating. These solutions are based in turn on the generalization, via the principle of high frequency localization, of the canonical solutions obtained for corresponding cylinder and sphere geometries. © 2012 IEEE.
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On an accuracy of the modified UTD solution for a convex impedance cylinder surface
(2012-10-02)
Phaebua, K.
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Phongcharoenpanich, C.
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Lertwiriyaprapa, T.
This paper presents an accuracy of a modified UTD solution for a convex impedance cylinder based on the general 3D UTD solution for a smooth convex perfectly electric conductor (PEC) scattering problem. By employing the impedance boundary condition (IBC), the modified UTD solution for a convex impedance cylinder can be used for the material-coated PEC cylinder problem. Thus, the modified UTD solution for a convex impedance cylinder surface requires the surface impedance value (Z <inf>S</inf>). In this paper, the study of the limitation of approximated closed form of Z <inf>S</inf> is presented. The thickness of thin material-coated PEC cylinder will be investigated in terms of the ratio of material-coated thickness to radius of the cylinder. The mean squared error (MSE) between the modified UTD results and the reference results obtained from CST-Microwave Studio program is performed to investigate limitation of closed form of Z <inf>S</inf>. The relative permittivity ε <inf>r</inf> of a material-coated PEC cylinder in this paper is fixed to 4. The modified UTD solution result shows good agreement with the CST-Microwave Studio commercial software for the dielectric-coated thickness up to d/a ≤0.07 or d/0.14λ for a=2λ. © 2012 IEEE.
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Path-loss prediction of radio wave propagation in an orchard by using modified UTD method
(2012-01-01)
Phaebua, K.
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Phongcharoenpanich, C.
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Krairiksh, M.
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Lertwiriyaprapa, T.
In this paper, the proposed theoretical path-loss prediction procedure and measured results of radio wave propagation in an orchard environment are presented. The path-loss prediction of wireless sensor network (WSN) in a durian (Durio zibethinus Murray) orchard is chosen to be an example of this study. The three-dimensional (3-D) modified uniform geometrical theory of diffraction (UTD) for curved impedance surface and the complex source point (CSP) technique for source modeling are employed for theoretical path-loss prediction in this paper. The orchard scenario is modeled using canonical geometries of UTD, such as a dielectric flat surface and cylindrical structures with an impedance surface to respectively represent ground and trees. Moreover, since the wireless sensor node is attached to the outside peel of a hanging durian fruit, the fruit partially acts as a wireless sensor node. Therefore, to obtain greater accuracy in the source radiation pattern, the Gaussian beam (GB) expansion via the CSP technique is used for source modeling. The path loss prediction from the proposed numerical procedure and the measured results are in good agreement. The proposed numerical procedure to calculate the path loss from actual scenario of the orchard is useful for network planning such as the pre-harvesting WSN system and other orchard scenarios.
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A triangular thin strip on-glass antenna for a DAB automotive application
(2011-11-01)
Phaebua, K.
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Phongcharoenpanich, C.
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Torrungrueng, D.
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Surittikul, N.
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Villarroel, W.
This paper proposes the design of a thin-strip on-glass antenna for a DAB automotive application. The proposed antenna uses a triangular thin-strip monopole as a radiating element, including a ground strip matching technique to obtain an improved impedance matching. The antenna radiation pattern, reflection coefficient [S<inf>11</inf> (dB)], polarization, and absolute gain in the operating frequency band are considered in the design process. It is found that an excellent omnidirectional pattern for vertical polarization, a good S <inf>11</inf> (dB) value, and an absolute gain larger than 0 dBi are achieved within the operating frequency band. © 2011 IEEE.
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A modified UTD solution for an impedance cylinder surface
(2011-08-12)
Phaebua, K.
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Lertwiriyaprapa, T.
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Phongcharoenpanich, C.
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Pathak, P. H.
This paper presents a modified uniform theory of diffraction (UTD) solution in 3D case for computing the electromagnetic (EM) field scattering from the impedance cylinder surface. The proposed solution based on the general 3D UTD solution for a smooth convex perfect electric conductor (PEC) scattering problem. Here, the Pekeris-integral function in the 3D UTD PEC solution is modified by using the impedance surface Pekeris-integral function and it is evalulated by using a numerical integration method without tabulated value. The modified UTD solution result shows good agreement when comparing with the exact solution and a commercial software. It is noted that this modified 3D UTD solution for a impedance cylinder surface will be very useful for predicting the field strength in the scenario modeling of the radio wave propagation. © 2011 IEEE.
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Application of UTD ray solution for characterization of propagation in Thai commercial orchard
(2010-12-01)
Lertwiriyaprapa, T.
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Phaebua, K.
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Phongcharoenpanich, C.
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Krairiksh, M.
The radio wave propagation model is theoretically proposed in this paper, by using the uniform geometrical theory of diffraction (UTD) together with the Gaussian beam (GB) via the complex source point (CSP) technique. The path loss and multipath propagation are predicted in a Thai commercial orchard. The durian orchard is primarily chosen to be an example for this study but the radio wave propagation model obtained in this work can be applied to any commercial orchard with slightly changing the scenarios in the orchard. To improve the source in the durian orchard modeling to be more practical, the GB expansion via the CSP technique is applied. In this work, one combines the UTD and CSP to deal with the path loss analysis in the durian orchard. This leads to the 3D propagation model of the durian orchard. This study will be very useful for designing the wireless sensor network (WSN) in any Thai commercial orchard. ©2010 IEEE.
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Electromagnetic wave scattering on 2D PEC cylinders using complex source point techniques and uniform geometrical theory of diffraction
(2010-07-30)
Lertwiriyaprapa, T.
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Phaebua, K.
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Phongcharoenpanich, C.
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Krairiksh, M.
An analysis of the path loss in the durian orchard is presented by using the complex source point technique (CSP) and the uniform geometrical theory of diffraction (UTD). The 2D Gaussian beams (GBs) expansion scattered by 2D cylindrical structures are presented. The GB can be generated by using the CSP. The GBs expansion can provides an efficient way of the synthesis of the radiation pattern of the antenna. The cylindrical structures are preliminarily assumed to be a perfect electric conductor (PEC). The source (square patch antenna) is located on a durian. The CST-program uses to simulate the source pattern including the effect of durian for the UTD calculation. The CSP-UTD is applied to analyze the scattered fields from the cylindrical structures. The multi-path propagation and the path loss prediction in various aspects are then obtained. Also, the exact solution of the CSP scattered by a cylindrical is used to compare the UTD results. The good agreements are obtained in this work.
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Path loss prediction in durian orchard using uniform geometrical theory of diffraction
(2009-11-16)
Phaebua, K.
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Lertwiriyaprapa, T.
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Phongcharoenpanich, C.
;
Krairiksh, M.

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