• Journal of electromagnetic engineering and science
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• v.11 no.1
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• pp.1-4
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• 2011

In this letter, we propose a novel tag antenna that has low performance degradation with nearby dielectric material. We obtained a stable reading performance and a broad matching bandwidth on nearby dielectric materials by employing a T-matching network with thick line width and capacitively slot-loaded arms. We then built the proposed antenna and measured the tag sensitivity to examine the reading characteristics with nearby dielectric materials. The measured results clearly demonstrate stable tag sensitivity with various nearby dielectric materials, such as foam, acrylic-plastic, glass, and ceramic plates. To more closely observe the antenna characteristics with nearby dielectric materials, we also examined the impedance variation and surface current distribution with respect to the dielectric constant of nearby target objects, which ranged from $1{\times}{\varepsilon}_0$ to $16{\times}{\varepsilon}_0$.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.11a
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• pp.405-408
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• 2005

This paper presents the characteristics of antenna factors for sleeve dipole antennas with a broad bandwidth. The coupled integral equations for the unknown current distributions on each elements are derived and solved by applying Galerkin's method of moments. The flatness of antenna factor is considered by variation of the length and number of sleeve elements.

• The Journal of the Korea institute of electronic communication sciences
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• v.3 no.2
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• pp.53-57
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• 2008

This paper designed and fabricated the printed dual monopole antenna with CPW feeder for PCS and UWB(Ultra-Wide Band) band. In this paper, modified dual monopole antenna is proposed transform conventional monopole antenna to get dual band frequency. The dual monopole antennas have dual band, broad bandwidth and omni-directional radiation patterns, as it is the conventional monopole antenna. As one monopole operated a stub to match feed line with antenna, we are obtained easy an ideal impedance matching. It is increased band width of impedance. The antenna bandwidth is about 1350MHz (1.69~2.04[GHz]z]) at 1st resonance frequency, 2,670MHz (4.33~6[GHz]) at 2nd, resonance frequency, and, 3,980MHz (6.1~10.08[GHz]) at 3th resonance frequency on VSWR$$\leq_-$$2, and then we can be got not only 1.75~1.87 [GHz] PCS band but also, UWB band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.5
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• pp.827-836
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• 2001

The L-shaped strip is shown to be an attractive feed for the thick microstrip antenna (thickness around 10% of the operating wavelength). The L-strip incorporated with the radiating patch introduces a capacitance suppressing some of the inductance introduced by the strip itself. In this paper, a wideband microstrip patch antenna fed by L-strip for the PCS (1,750~1,850 MHz) and IMT-2000 (1,920~2,170 MHz) broad-band is presented. A two-element array fed by L-strip is also proposed. Both the antennas have stable radiation patterns across the passband. The impedance bandwidth is over 31% (VSWR < 1.5, 615 MHz) of the center frequency. Moreover, both the antennas have about 7 dBi average gain.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.2
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• pp.188-193
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• 2004

In this paper, a microstrip array antenna utilized a subarray with a waveguide slot feeding is presented. This subarray can reduce the feed loss compared with a full microstrip feed network. The subarray has been designed both for a broad reflection bandwidth and a flat gain bandwidth from 40.5 GHz to 43.5 GHz. The 24${\times}$24 series-fed array antenna has been implemented with the maximum gain of 32.4 dBi.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.7
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• pp.72-76
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• 2008

In this paper, the several printed square loop antennas which modified monopole antennas are proposed. The proposed antennas are reduced about 20% physical size of antenna and miniaturized reactance value of impedance due to fold center part of the loop. They obtained omni-directional radiation patterns with broad bandwidth and feed method used coplanar waveguide to composed single planar. The proposed antenna bandwidth is about 900MHz($2.63{\sim}3.56GHz]$) resonance frequency on $VSWR{\le}2$. it can be sufficiency of S-DMB band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.5
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• pp.755-762
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• 2000

In this work, we present the resonant frequencies, Qrad, and impedance bandwidth of rectangular dielectric resonator antenna(DRA)for a broad range of aspect ratios using Dielectric Waveguide Model. These presented data are compared with simulation and measurement. The DRA having relative permittivities of 37.84 and 90 have been fed by a coaxial cable and fed using a aperture-coupled method for comparisions. The approximate resonant frequencies are shown to have the prediction error of about 8% and impedance bandwidth is found to have large prediction variation according to feeding method. The data presented in this paper can be used when the aspect ratios of DRA have to be determined for a given resonant frequency and impedance bandwidth.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.11
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• pp.99-104
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• 2003

We are designed and fabricated the Printed dual monopole antenna with CPW feeder for PCS and IMT2000 band. In this paper il proposed modified dual monopole antenna that is transform conventional monopole antenna to get dual band frequency. The dual monopole antennas had broad bandwidth and omni -directional radiation patterns in construct with conventional monopole antenna. On a monopole operated a stub to other monopole antenna, we could obtain easy an impedance matching. It is increased band width of impedance. The antenna bandwidth is about 150MHz(1.74 ∼1.89〔GHz〕)at 1$^{st}$ resonance frequency and 290MHz(1.95∼2.24GHz) at 2$^{nd}$ resonance frequency on VSWR(equation omitted)1.5 and then we can be got not only 1.75∼1.87〔GHz〕 PCS band but also 1.92∼2.17 〔GHz〕).GHz〕).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.2
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• pp.96-103
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• 2003

A cavity-backed microstrip patch antenna for a monopulse radar system is designed and fabricated. Also, this antenna is shown to be suitable for the system by analyzing the measured results. Since the azimuthal beamwidth required by this system is quite broad compared to that of a usual microstrip antenna, the width of a microstrip patch is reduced considerably. The decrease of an antenna bandwidth due to the reduced patch width is compensated by increasing the effective substrate thickness. A detection range and a detection probability is calculated from the measured gain at a given angle, and this result shows that the fabricated antenna can be applied well to this monopulse radar system.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.345-349
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• 2000

A microstrip polarized 8${\times}$2 linear phased array antenna with four 4-bit phase shifters is designed at 10 GHz. The 180$^{\circ}$and 90$^{\circ}$ sections of the phase shifter are of the switched line type, and the rests are of the loaded line type. A 2${\times}$2 sequential sub-array is adopted for a broad axial ratio bandwidth. The construction of the array antenna is of the tile type placing the phase shifters on the same layer containing the feed network. The element spacing is chosen to be 0.45λ$\sub$0/ to exclude the grating lobe. Measurement results show a gain 9.69 dB at broadside and 8.3 dB at the beam-tilt angle of 16$^{\circ}$ by imposing a progressive phase of 90$^{\circ}$.