• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.1-4
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• 2004

In this paper we developed Composite-Smart-Structures(CSS) using sandwich structure composed of Glass/Epoxy laminates and Nomex honeycomb and microstrip antenna. Transmission/reflection theory shows that antenna performances can be improved due to multiple reflection by Glass/Epoxy facesheet, and honeycomb is used for air gap between antenna and facesheet. Stacked radiating patches are used for the wideband. Facesheet and honeycomb thicknesses are selected considering both wideband and high gain. Measured electrical performances show that CSS has wide bandwidth over $10\%$ and higher gain by 3.5dBi than initially designed antenna, and no doubt it has excellent mechanical performances by sandwich effect given by composite laminates and honeycomb core. The CSS concept can be extended to give a useful guide for manufacturers of structural body panels as well as antenna designers, promising innovative future communication technology.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.8 s.338
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• pp.47-54
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• 2005

The design method for a dual frequency antenna using CPW feed lines is presented. The antenna structures can be simplified by CPW feed lines and easily designed on integrated circuits. The presented antenna has two resonant frequency ranges and each respective resonant frequency is determined by its own length of monopole antenna. We used an impedance matching method by using a monopole coupling related to the ground of CPW feed lines As a result, the resonant frequencies were 5.25[GHz] and 23.5[GHz] and their bandwidths $35.2\%,\;and\;41.3\%$, respectively, and also, the separation of the two frequencies $370\;%$. We presented an analytical designing method to implement a dual frequency monopole antenna and showed simple antenna structures having two frequency ranges for RFIC Integrations.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.303-306
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• 2005

In this paper, a CPW-fed monopole antenna using inverted L-type DGS structures is proposed and investigated experimentally. The proposed antenna is fabricated into FR4 substrate with dielectric constant($\varepsilon$r=4.5). Measured results show that the impedance bandwidth, determined from 10-dB return loss, for frequencies between 5.7250Hz-5.825CHz under the condition of VSWR$\leqq$2 is about 540MHg.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.4
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• pp.24-31
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• 1998

The far-zone magnetic field patterns of a E-plane horn antenna with various edge structures are analyzed using UTD. The ray tracing method is used to lacate the shadow boundaries, and then GO and UTD are utilized to evaluate the incident, reflected, diffracted, surface diffaracted, and the second order diffracted, diffracted-reflected, and diffracted-reflected-diffracted waves existing in each region of interest. By doing this, we analyzed the effects of flanges or caps connected on the edge of a horn antenna on the side lobe and back lobe levels. Also, the validity of this paper is proved by comparing the analytical results with those of measurement and method of moment presented in the reference.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.12
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• pp.1-10
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• 1999

In this paper, we analyzed the radiation patterns of a monopole antenna mounted on the complex structures by using FDTD method associated with 3-D PML absorbing boundary condition. In order to validate the proposed FDTD code, the radiation patterns of monopole antenna mounted on cylinders and spheres were compared with the exact solutions of $Carter^{[1]}$ and $Harrington^{[2]}$. For all case considered, the predicted radiation pattern exhibited excellent agreement with exact solution. To be able to model the more complex structures, the proposed FDTD methods are combined with BRL-CAD. And this procedures is applied to predict the radiation patterns of a wire antenna attached to the top of a Blackhawk helicopter.

• Journal of electromagnetic engineering and science
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• v.18 no.2
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• pp.108-116
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• 2018

In this paper, a method of designing a Vivaldi type phased array antenna (PAA) which operates at S-band (2.8-3.3 GHz) is presented. The presented antenna uses broadside coupled split ring resonators (BC-SRRs) for high isolation, wide field of view, and good active S-parameter characteristics. As an example, we design a $1{\times}8$ array antenna with various BC-SRR structures using theory and EM simulations. The antenna is fabricated and measured to verify the design. With the BC-SRR implemented between the two radiating elements, the isolation is shown to be enhanced by 6 dB, up to 23 dB. The scan angle is shown to be within ${\pm}53^{\circ}$ based on a -10 dB active reflection coefficient. The operation of the scan angle is possible within ${\pm}60^{\circ}$ with a little larger reflection coefficient (-7 dB to -8 dB). The proposed design with BC-SRRs is expected to be useful for PAA applications.

• Composites Research
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• v.22 no.3
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• pp.55-59
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• 2009

Microstrip antennas are low profile, are conformable to planar and nonplanar surfaces, are simple and inexpensive to manufacture, mechanically robust when mounted on rigid surfaces and are compatible with MMIC(Monolithic microwave integrated circuit) designs; they have been used in diverse communication systems. The rectangular microstrip patch antenna is designed for a central frequency of 12.5 GHz, and the final product is a $4{\times}1$ array antenna with curvature radius of 200 mm. The microstrip antenna is embedded in a sandwich structure which consists of skin and core material. After impact, the performance of damaged antenna is estimated by measuring the return loss and radiation pattern. The antenna performance was not affected by this impact damage.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.119-122
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• 2001

In this paper, an elliptic disk-loaded antenna having frequency shift characteristics with the same height of the simple monopole is studied. The proposed antenna is composed of an ellitptic disk with arbitrary ellipticity ratio. The eigenmode representations in each region of given structure are useful for the analysis of the canonical monopoly, circular disk-loaded monopole and circular dielectric-loaded top-hat monopole antennas using the artificical ground plane. The comparison between the elliptic and circular disk-leaded antenna is carried out. The effect of the shape of the loaded disk and the ellipticity ratio of the loaded disk on the input impedances, the return loss and frequency shift is also studied. We have computed the given structures using the CST MW Studio version 3.0. The typical blade antenna can be obtained by modifying and extending the proposed structure with the λ/4 balun removing the stray capacitances existing between the loaded disk and the ground plane.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1389-1390
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• 2008

In this paper, a This paper presents the Hilbert curve Fractal Antenna has properties of Self-similarity and Plane-Filling. In case of fractal antenna is very useful to be small and multiple resonant. The antenna has a resonant frequency of 910MHz and 2450MHz base on RFID(Radio Frequency IDentification). In particular, we designed tag antenna by the $4^{th}$ repeat. According to the repeated number of fractal structures, resonance frequency became looking downward. Theses presented Frequency, Such as 910MHz and 2450MHz, at $S_{11}$ is -31dB and -19dB, bandwidth 120MHz and 90MHz to VSWR 2:1.

• ETRI Journal
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• v.32 no.1
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• pp.62-67
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• 2010

In this paper, an ultra-wideband internal antenna for use in mobile applications is proposed. The proposed antenna has symmetrical bi-arm structures printed on the top and bottom of the substrate, and it occupies a compact area of 10 mm ${\times}$ 10 mm ${\times}$ 1 mm. The designed antenna has an impedance bandwidth from 3 GHz to 12 GHz and near omnidirectional radiation patterns over the frequency band of interest. The group delay between two antennas fabricated using the proposed design is less than 0.8 ns, and the maximum gain variation is about 3.16 dB.