• The Journal of Korea Robotics Society
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• v.11 no.3
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• pp.156-162
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• 2016

For the underwater localization, acoustic sensor systems are widely used due to greater penetration properties of acoustic signals in underwater environments. On the other hand, the good penetration property causes multipath and interference effects in structured environment too. To overcome this demerit, a localization method using the attenuation of electro-magnetic(EM) waves was proposed in several literatures, in which distance estimation and 2D-localization experiments show remarkable results. However, in 3D-localization application, the estimation difficulties increase due to the nonuniform (doughnut like) radiation pattern of an omni-directional antenna related to the depth direction. For solving this problem, we added a depth sensor for improving underwater 3D-localization with the EM wave method. A micro scale pressure sensor is located in the mobile node antenna, and the depth data from the pressure sensor is calibrated by the curve fitting algorithm. We adapted the depth(z) data to 3D EM wave pattern model for the error reduction of the localization. Finally, some experiments were executed for 3D localization with the fast calculation and less errors.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.1
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• pp.19-24
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• 2014

In this paper, a multiband LTE antenna satisfying LTE octa-band is proposed. The proposed antenna consists of a modified PIFA structure and a folded monopole which has the height of 4 mm. Each parts operates at lower and upper LTE band. Measured bandwidth(6 dB return loss) was 118 MHz(870~988 MHz) at the lower band and 1,107 MHz(1,650~2,757 MHz) at the upper band. The proposed antenna has a omni-directional radiation pattern and measured peak gains were 3.21 dBi at the lower band and 4.19 dBi at the upper band, respectively. The proposed antenna is expected to be utilized for future LTE-advanced system.

• 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.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.7
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• pp.75-79
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• 2004

In this paper, a single plane wide band microstrip antenna for integrated circuit as MMIC and LTCC is designed and fabricated. A new configuration for a wide band microstrip antenna with omni-directional pattern is proposed. This antenna consists of two rectangular folded dipoles, which are fed by a coplanar waveguide(CPW). It was effected stabilization ground that a signal plane of CPW feed have been limited ground plane. Therefore, a ground plane of folded structure should be extended outside folded antenna in this research. The characteristics of the proposed antenna were analyzed by using an FDTD methods. The return loss and radiation patterns were simulated and measured. The proposed antenna is get 120MHz bandwidth of PCS band and 250MHz bandwidth of IMT2000 band, used ISM band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.10 s.89
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• pp.915-921
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• 2004

In this paper, we propose a printed monopole antenna called the saw tooth monopole antenna(STMA) with a very wide band. And impedance matching of the antenna for the wideband is achieved using a special matching structure to vary ground size of back plate. The proposed antenna is smaller than general $\lambda$/4 monopole antenna in size but provides a 2:1 VSWR bandwidth of about $89.6\%$. The radiation pattern is omni-directional at 0.8 GHz$\~$2.0 GHz with gain of about -0.02 dBi$\~$2.54 dBi.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1414-1416
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• 2016

In this paper, a SWB (Super-WideBand) dipole antenna with self-complementary structure is proposed for signal intelligence. The proposed antenna consists of a self-complementary dipole antenna and a tapered balun for balanced feeding. The measured -10 dB reflection bandwidth of the proposed antenna is more than 28:1 (0.73-20 GHz) and 3 dB axial ratio bandwidth is 3.25:1 (1.91-6.22 GHz) with RHCP (Right Hand Circular Polarization) at +z direction. The measured radiation patterns are omni-directional in lower frequency band and bi-directional in higher frequency band. The measured peak gain within -10 dB reflection bandwidth varies from 2.83 dBi to 7.66 dBi.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.6 s.97
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• pp.563-570
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• 2005

In this paper, a small-sized planar square-spiral monopole antenna is proposed by using parasitic elements. The Parasitic element is composed of a crossed strip and additional right-angle folded(L-type) stirps. And these parasitic elements are printed on a substrate which is the opposite side of a radiation element . When the parasitic elements are used, the size of the square-spiral monopole antenna is reduced by $32\%$ for the same operating frequency compared to the antenna without parasitic elements. The radiation pattern of the proposed antenna is nearly omni-directional in azimuth. The designed antenna can be used in the application of channel 12 digital mulimedia broadcasting(DMB) handset.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.11
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• pp.1051-1061
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• 2004

In this Paper, a new antenna(VHMDA) characteristics of half-circular/elliptical disc-loaded planar antennas with horizontally top-loaded small disc is studied by simulation and measurements with additional resonant structure. The transfer function characteristics of Gaussian pulse from the designed UWB transmitter antenna has been investigated. The radiation pattern of the proposed antenna in azimuth is nearly omni-directional response, which is usulally required in conventional monopole antenna. In addition to that, the simulation and measured results show that the return loss characteristics of VHDMA covers considerably large bandwidth with small area. From the measured results of the circular and half-circular disc-loaded monopole antennas with small disc mounted on the top, it is found that the half disc-loaded monopole antenna with additional structure can be comparable to the circular disc-loaded monopole antenna in respect o( size and electrical performances. Surface wave and dielectric losses often caused by the printed antenna using high dielectric constant does not occur in metallic planar antenna with good impedance matching and without lossy matching unit. This structure implies that the performance of return loss is directly related with the radiation efficiency.

• Journal of Advanced Navigation Technology
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• v.24 no.2
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• pp.142-147
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• 2020

In the present study, we proposed newly a CPW-fed miniaturized folded-slot antenna with open ended slot for WCDMA (1.92 ~ 2.17 GHz) band. Open-ended slots and asymmetric ground plane are used for a miniaturization of the antenna, and the proposed antenna was designed and fabricated on a FR-4 substrate with dielectric constant 4.3, thickness of 1.6 mm, and size of 35×70 ㎟. The measured impedance bandwidths (|S₁₁| ≤ -10 dB) of fabricated antenna is about 400 MHz (1.86 ~ 2.26 GHz), which sufficiently satisfied interested band. Furthermore, the gain of antenna is 2 dBi and this antenna shows a similar radiation patterns of the dipole antenna. Therefore, it is expected to be used usefully in wireless and mobile communication device.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.12 s.103
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• pp.1194-1205
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• 2005

This paper proposes a uni-planar elliptical element UWB antenna with band-notched characteristic and modified pound plane fed by CPW. The antenna achieves VSWR below 2 for UWB band(3.1 GHz${\~}$10.6 GHz). In addition, a band-notched characteristic is achieved by inserting a horizontal slot on the radiation element to avoid the interference with 5 GHz(5.15 GHz${\~}$5.825 GHz) band limited by IEEE 802.1la. The antenna has a thin profile, compact size, and ease of manufacture by adopting a CPW feed structure without any additional background plane. Measured data show that the proposed antenna has good return loss below -10 dB, about 2.1 dB${\~}$4.75 dB maximum gain over the bandwidth, omni-directional radiation patterns, linear phase response.