• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.141-144
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• 1998

An L-band omnidirectional circular polarized wave antenna is designed and evaluated for transmitting/receiving of vehicle data. Conventional linear polarized wave antenna can not reveive clearly all of the vehicle data which come from the wide driving test range on account of distortion. To overcome this problem, an omnidirectional circular polarized wave antenna is required for the design, first of all, the characteristics, design principle and theoretical background of circular polarized wave with a little signal loss have been reviewed. The designed antenna characteristics an analysed and compared to the desired ones. Our results demonstrate that the strength of vehicle data is flat enough over the full test range using this new antenna.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.11
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• pp.1133-1136
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• 2011

In this paper, we proposed a collinear antenna with a stripline structure for IEEE 802.11b/g applications in ISM (Industrial, Scientific, Medical) band of 2.4~2.5 GHz, which supplements disadvantages of COCO(Coaxial Collinear) antenna and OMA(Omnidirectional planar Microstrip Antenna). By using the proposed 4-layer substrate, we obtained improved performances and advantages in production compared with the existing antenna. In order to get antenna arrays, the same phase structure is designed by alternatively connecting outer conductor to inner conductor with ${\lambda}$/2 antenna element, and the substrate of FR4 epoxy (${\epsilon}_r$=4.4, tan${\delta}$=0.02) was used for the actual implementation. The maximum gain of about 4.93 dBi was measured, which leaded to a little improved gain of 0.33 dBi in comparison to the existing OMA structure.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.11
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• pp.1050-1056
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• 2015

In this paper, we use the characteristics of electromagnetic waves underwater attenuation for estimating linear distance between a transmitting node and receiving node, and research underwater vertical plane attenuation model for constructing the underwater localization system. The underwater localization of 2 dimensional with the plane attenuation model in the horizontal plane (H-plane) was proposed previous research. But for the 3 dimensional underwater localization, the additional vertical plane (E-plane) model should be considered. Because the horizontal plane of omnidirectional antenna has the same attenuation tendency in x-y plane according to the distance, whereas in vertical plane shows an irregular pattern in x-z plane. For that reason, in the vertical plane environment, the attenuation should be changed by the position and inclination. Hence, in this paper the distance and angle between transmitting and receiving node are defined using spherical coordinate system and derive an antenna gain pattern using half power beam width (HPBW). The HPBW is called a term which defines antenna's performance between isotropic and other antennas. This paper derives omnidirectional antenna's maximum gain and attenuation pattern model and define vertical plane's gain pattern model using HPBW. Finally, experimental verifications for the proposed underwater vertical plane's attenuation model was executed.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.598-600
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• 2003

Ad­hoc 무선 망에서 directional antenna의 사용은 interference를 감소시키고 spatial reuse의 증가, 그리고 네트워크 전체의 capacity 증가 등의 장점을 제공한다. 하지만 기존의 IEEE 802.11 MAC protocol은 omnidirectional antenna를 고려하여 디자인되었기 때문에 기존의 MAC protocol이 directional antennas에 사용될 경우 directional antennas의 장점을 효율적으로 제공하지 못한다. Directional antenna는 이러한 장점을 가지는 반면에 RTS/CTS를 방향성 있는 전송을 하기 때문에 hidden terminal과 이웃 노드의 위치를 파악하는데 있어서 많은 문제를 가지고 있다. 이 논문에서 우리가 제안하는 MAC protocol은 directional antennas 특성상의 문제점을 해결하여 directional antennas의 장점을 최대한 이용한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1744-1751
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• 2006

In this paper shows the Designed and Manufactured active antenna for wireless LAN that is consisted of 5.5GHz band local LNA and Microstrip Patch Antenna. LNA improved noise special quality using NEC company's NE3210S01 and Micnstrip Patch Antenna designed to have omnidirectional characteristic. Designed $1{\times}2$ Microstrip Patch Antenna to have the gain of about 8.3[dBi], the input reflection loss -32[dB], VSWR showed 1.132, and the LNA gain 15[dB], input-output reflection loss was showed the characterstic of -20[dB].

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.7
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• pp.1558-1564
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• 2004

This paper shows the design of Active antenna which appled to 5.5GHz RF module for local wireless communication system. The LNA, which was designed Super low noise HJ FET of NE3210S01, is used to obtain a good noise figure characteristics. And the microstrip patch antenna was designed to obtain omnidirectional antenna characteristics. The measured LNA gain is 15 dB, input & output return loss is under -20 dB and VSWR under 1.5. The Single microstrip patch antenna input return loss is under -29 45, VSWR under 1.2.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.2 s.93
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• pp.204-210
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• 2005

In this paper, we are proposed the antennas for RFID tag operated at UHF band which are inserted ground plane easy to mount the RFTD chips at the antenna surfaces. In order to implemented antenna for RFID tag which the size is same as conventional name card, the structure of the antenna is meander type, matching method for improvement characteristics of the antenna use T matching method, ground plane is inserted at the antenna substrate fer mounting RFID chips. The substrate size of implementation is $100\times60\;mm^2$ and the FR4 substrate is used. Results of the experiment, the center frequency of the implemented antenna is 427 MHz, -10 dB return loss bandwidth is 8 MHz, maximum return loss is 21 dB, the radiation pattern is omnidirectional. From these results, we are conformed application for UHF RFID tag antenna.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.5
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• pp.18-23
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• 1998

Development of an automobile antenna printed on-glass for FM radio receptions was discussed in this study. NEC-2 code was used as the design tool in this research. An omnidirectional radiation pattern and reception power level of the newly designed antenna were compared with those of the conventional pole antenna for the evaluation of its performance. The test sites for the reception power level measurement were chosen by their signal enbironmental condition, such as multipath fading, and strong field effect area.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.213-219
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• 2015

In this paper, we present a low-profile ultra-wide band half-wavelength loop antenna for UAV (Unmanned Aerial Vehicle) applications. The proposed antenna has an ultra-wide band using self-complementary principle. Also, the ground was located between radiators for reducing height of the antenna using image theory. Dimensions of proposed antenna have $0.20{\lambda}_L{\times}0.14{\lambda}_L{\times}0.16{\lambda}_L$ (${\lambda}_L$ is the free-space wavelength at lowest frequency). Measured -10 dB bandwidth was ultra-wide band as more than 50 : 1(over 0.3 GHz ~15 GHz). The radiation patterns of the antenna was omnidirectional like monopole antennas. Moreover, we tried the antenna mounted on under a fuselage of a scaled UAV. As a result, the proposed antenna on the UAV maintained ultra-wide band and omnidirectional radiation patterns at all frequencies.

• ETRI Journal
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• v.42 no.1
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• pp.7-16
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• 2020

Assuming omnidirectional antenna reception, the ITU-R recently developed a new propagation model on building entry loss (BEL) for 5G millimeter-wave frequency sharing and compatibility studies, which is a simplified outdoor-to-indoor path loss model. Considering the utilization of high-gain narrow-beamwidth beamforming, the omnidirectional-based ITU-R BEL model may not be appropriate to predict propagation characteristics for directional beamforming scenarios. This paper studies the effects of beamwidth on the ITU-R BEL model. This study is based on field measurements collected with four different beamwidth antennas: omnidirectional, 10° horn, 30° horn, and 60° horn. The measurement campaigns were conducted at two types of building sites: traditional and thermally efficient buildings. These sites, as well as the measurement scenarios, were carefully chosen to comply with the ITU-R BEL measurement guidelines and the ITU-R building types. We observed the importance of accurate beam alignment from the BEL variation range. We were able to quantify the beamwidth dependency by fitting to a model that is inversely proportional to the beamwidth.