• Journal of electromagnetic engineering and science
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• v.17 no.3
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• pp.159-164
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• 2017

This article proposes a design of chipless RFID tag with dipole array structure that is fully printable using conductive ink. The proposed tags encode data based on spectral signature modulations. The reading range is considerably increased (2 m) while maintaining low transmission power (1 mW). Several prototype chipless RFID tags were fabricated and measured in the SHF and UHF bands. The proposed dipole array structure enhances the antenna gain of the passive tags and contributes to overcoming the low conductivity of conductive ink. In order to verify the utility of our proposal, the tags are manufactured on paper, using conductive ink, for the purpose of economic mass production.

• Journal of electromagnetic engineering and science
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• v.10 no.3
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• pp.171-174
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• 2010

In the paper, a printed dual-dipole array antenna is presented. A 4-way planar SIW power divider is adopted for feeding the array antenna. The dual-dipole is adopted as radiation elements which greatly improves the impedance band. The measured bandwidth larger than 31 % for VSWR$\leq$1.5 operating near 14 GHz is achieved and in agreement with the simulated results. The radiation E-plane and H-plane radiation pattern is presented in the paper. The radiation gain is also presented in the paper.

• Journal of the Korean Geophysical Society
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• v.6 no.3
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• pp.155-164
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• 2003

The validity and efficiency of the roll-along technique widely used in 2-D electrical resistivity survey are analyzed in case of the dipole-dipole and the Wenner-Schlumberger arrays by numerical modelling. The shallow anomalous resistivity bodies are successfully inverted both in the dipole-dipole and in the Wenner-Schlumberger arrays because the shallow data of pseudosection are not omitted by the roll-along technique. However, the deep anomalous resistivity bodies can not be well resolved due to the skip of observed data which is more significant in the Wenner-Schlumberger array having relatively poor horizontal coverage of obtaining data. Carrying out electrical survey adopting the dipole-dipole array, the skip of data is insignificant because it is unfeasible to expand the electrodes to the maximum electrode separation coefficient($n_max$) owing to low S/N ratio. In case of the Wenner-Schlumberger array, however, because it is generally feasible to expand the electrodes $n_max$ to the owing to high S/N ratio, it is highly possible that skip of data from the roll-along technique causes significant distortion of inversion results. Therefore, adopting the Wenner-Schlumberger array having deeper median depth(Edwards, 1977) than do the dipole-dipole array on condition of the same unit electrode spacing( ($a$) ) and $n_max$, it is recommended to determine $a$ based on not $n_max$but $n_prob$free from the skip of observing data and forward electrodes with keeping overlap interval 3/4 of the survey line length in order to reduce the distortion of resistivity structure and perform resistivity survey efficiently. These results are confirmed by numerical modelling.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.2
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• pp.41-51
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• 2004

In this paper, the beam steering dipole phased array antenna systems for IMT-2000 base station have been designed. The designed beam steering dipole phased array antenna systems are constituted by the antenna part and the beam steering control system part. The antenna part is designed by the proposed flat dipole for the broadband characteristics, and the 8${\times}$8 dipole array antenna is constructed by the proposed flat dipole for the directional radiation pattern. Besides the vertical power divider is designed for the vertical power distribution. The beam steering control system part is designed the horizontal power divider for the horizontal power distribution, the 4-bit phase shifters and the driving circuit of phase shifters for the horizontal beam tilting. In order to evaluate a performance of the designed antenna systems, they were fabricated and the radiation characteristics were measured. From the measured results, we found that the horizontal beams were tilted by the each control signals, and the measured radiation characteristics showed good agreement with the design goals.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.7A
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• pp.678-682
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• 2011

In this paper, a compact log periodic dipole array (LPDA) antenna operating from 1 to 6 GHz is studied. Inverted-L shaped dipole elements are used to miniaturize the lateral size of an LPDA antenna and the spacing factor is also decreased to reduce the total length of the LPDA antenna. As the top-loading length of the inverted-L shaped dipole elements is increased, the width of the LPDA antenna is decreased but the bandwidth and the gain of the antenna are decreased. The fabricated compact LPDA antenna is printed on FR4 substrate With a dielectric constant of 4.4 and a thickness of 1.6 mm, and its size is reduced to 32% in width and 49% in length compared to a standard LPDA antenna.

• Journal of electromagnetic engineering and science
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• v.12 no.4
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• pp.254-259
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• 2012

This paper presents a closely spaced two-element folded-dipole-driven quasi-Yagi array with low mutual coupling between adjacent elements. The antenna utilizes a T-junction power divider as the feeding network, with an input impedance of $50{\Omega}$. A microstrip-stub is added to the ground plane in the middle of the two elements to improve the mutual coupling characteristics. The folded dipole driver is connected to a $50{\Omega}$ microstrip line via a broadband microstrip-to-coplanar stripline transition with a quarter radial stub. A mutual coupling of less than -22 dB is measured between two folded-dipole-driven quasi-Yagi antennas with a center-to-center spacing of 30 mm ($0.55{\lambda}_0$ at 5.5 GHz). The proposed quasi-Yagi array yields a measured bandwidth of 4.75~6.43 GHz for the -10 dB reflection coefficient and a gain of 6.14~7.12 dBi within the bandwidth range.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.6
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• pp.1057-1062
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• 2016

In this paper, a design method for a compact log-perio dic half-bow-tie dipole array antenna for an operation in a UWB band(3.1-10.6 GHz) is studied. The proposed antenna is miniaturized by using half-bow-tie shaped dipole elements instead of strip-type dipole elements, which are commonly used in a general log-periodic dipole array(LPDA) antenna, and by reducing the element spacing. The effects of the flare angle of the half-bow-tie elements and the spacing factor on input reflection coefficient and realized gain characteristics of the proposed log-periodic antenna are analyzed. The optimized antenna is fabricated on an FR4 substrate, and the experiment results show that the antenna has a frequency band of 2.95-11.31 GHz for a VSWR < 2, which assures the operation in the UWB band. In addition, the length and width of the proposed antenna are reduced to 32.1 % and 18.3 %, respectively, compared to the LPDA antenna.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.19-21
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• 1997

This paper treated a new method that generates the dipole magnetic field for high speed machines by using Halbach array, which was suggested by Klaus Halbach. The Halbach array can produce the various field distribution without magnetic materials. Therefore, the iron losses can be reduced. This paper presented the magnetic characteristics on both linear and cylindrical Halbach array. And the Halbach array for dipole field was manufactured with Nd-Fe-B magnets having 1.17(T), the measured flux density was compared the theoretical values acquired by three dimensional FEM analysis. Finally, the magnetic characteristics of Halbach array were compared with those of other conventional dipole field systems.

• Steel and Composite Structures
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• v.17 no.5
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• pp.561-572
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• 2014

In this paper, we present the scattering characteristics of infinite and finite array using method of moment (MoM) with Floquet harmonics and asymptotic waveform evaluation (AWE) technique. First, infinite cylindrical dipole array is analyzed using the MoM with entire domain basis function and cylindrical Floquet harmonics. To provide the validity of results, we fabricated the cylindrical dipole array and measured the transmission characteristics. The results show good agreements. Second, we analyzed the scattering characteristics of finite array. A large simulation time is needed to obtain the scattering characteristics of finite array over wide frequency range because Floquet harmonics can't be applied. So, we used the MoM with AWE technique using Taylor series and Pade approximation to overcome the shortcomings of conventional MoM. We calculated the radar cross section (RCS) as scattering characteristics using the proposed method in this paper and the conventional MoM for finite planar slot array, finite spherical slot array, and finite cylindrical dipole array, respectively. The compared results agree well and show that the proposed method in this paper is good for electromagnetic analysis of finite FSS.

• ETRI Journal
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• v.20 no.1
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• pp.46-54
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• 1998

An analysis method of electromagnetic scattering from periodic patch array of double-dipole elements on a grounded dielectric substrate in case of oblique incident and arbitrary polarization is considered. The basis functions are chosen to be entire consinusoidal functions are chosen to be entire consinusoidal functions covering the rectangular shaped domain in which the original dipoles are inscribed, unlike the conventional method in which basis functions are defined only for the conducting element region. To confirm the validity of the proposed analysis method, we calculate the normalized scattered power for two propagating modes and compare the results with those obtained by the previous numerical method for the double dipole elements of rectangular type and parallelogram type which have the property of frequency scanned reflection and polarizer. Good correspondence has been observed between them. Some numerical results such as variation of power and axial ratio of first-order diffracted wave by a periodic array of double-dipole elements are compared with previous results.