• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.12
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• pp.1327-1336
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• 2007

In this paper, we propose a reconfigurable antenna which operates as a disk-loaded dipole antenna and a folded dipole antenna alternatively using RF on/off switches. The antenna can change its effective length to achieve dual-band operation; operates as the folded dipole antenna for stepping up the radiation resistance in low frequency band of $20{\sim}300$ MHz, and as the disk-loaded dipole antenna for an omni-directional radiation pattern (horizontal plane) and a donut-shaped radiation pattern (vertical plane) in high frequency band of $300{\sim}1.3$ GHz. In the low band, the proposed antenna shows higher gain than a conventional dipole antenna with a reduced antenna size. In the high band, the antenna maintains a broad beamwidth of about $80^{\circ}$, thus the antenna can be applicable to antennas for direction finding applications.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.5
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• pp.515-522
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• 2008

In this paper, a slot antenna with built-in Bazooka balun aimed for a WiBro repeater was designed and fabricated. The return loss and radiation pattern of the slot antenna were improved due to the introduced Bazooka balun. This balun brings about even radiation pattern and keeps the stabilized coverage of repeater And it is easy to unite this balun with the antenna body by providing the terminal of Bazooka balun with screw shape. H-type slot was used to reduce the size of the antenna, and the slot antenna was fabricated in the structural symmetry with respect to a feeding point to afford the omni-directional radiation pattern. The simulated results were obtained by MWS(Microwave Studio Simulator) of CST company, and the measurement on the proposed antenna was conducted in an anechoic chamber equipped with a network analyzer and a far field measurement system. The measured peak gain shows 5.75 dBi and the average gain is above -0.8 dBi. The return loss remains below -12.35 dB for all frequency bands in WiBro regarded as a good performance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.3
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• pp.336-344
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• 2011

The purpose of this study is to analyze the radiation-pattern characteristics above 1 GHz for the electromagnetic wave radiated from multi-slot such as ventilations, etc. on the enclosure of an EUT and so to make recommendations for suitable test methods. An experimental EUT was formed by putting a comb-generator at the center of a rectangular enclosure with 4 slots, and its radiation pattern was analyzed in the frequency range of 1~6 GHz. As analysis results, multi-lobe appears above 2 GHz and the number of multi-lobes is growing as the frequency increases. And real radiated-emission measurements were performed for the experimental EUT by scanning a receiving antenna in the height of 1~4 m and tilting toward maximum radiation, as well as setting the height of a receiving antenna to the central position of the EUT which is prescribed at the present standards. The measured results are +12.8 dB in the scanning and +16.4 in the scanning and tilting compared with the present standard test method. Therefore, the latter must be revised in order to consider the radiation pattern above 1 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.1
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• pp.109-121
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• 1999

In this paper, HF band LPDA(Log-periodic Dipole Antenna) and MLPDA(Modified Log-periodic Dipole Antenna) above lossy grounds were analyzed using moment method by considering the practical media parameter of lossy grounds, not assuming free space or perfect ground approximation. The radiation pattern and gain of LPDA and MLPDA as functions of frequency, antenna height from ground, and antenna tilt angle are presented, and the lossy ground effect on antennas characteristics are described. MLPDA was found to exhibit a smaller variation for gain and radiation pattern and a higher maximum beam direction relative to LPDA. It was shown that media parameter of lossy grounds and antenna height have a direct influence on the antenna gain of both LPDA and MLPDA.

• Journal of Broadcast Engineering
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• v.23 no.6
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• pp.925-930
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• 2018

In this paper, we present a low profile dual-microstripline-fed double 4-arrayed meander monopole antenna with a cross-type element back by separated four-segments mesh-type reflector. The cross-type element and separated four-segments mesh-type reflector leads to enhance radiation patterns and antenna gain characteristics. The measurement value of the proposed antenna show that it has dipole-like radiation pattern characteristics. The experimental peak gain of fabricated antenna is about 2.89 dBi, which presents relatively high gain characteristics for a low profile(small-size) one. This antenna can be applied mobile RFID(radio frequency identification) readers, small medical instruments, broadcasting and home-networking operations, and other low profile high-gain systems.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.2 s.105
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• pp.193-197
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• 2006

Radiation properties of flush mounted circular patch antennas are investigated. The patch is fed axis-symmetrically by a coaxial cable. Rigorous analysis iscarried out using integral transform and mode matching techniques. The presented method can accommodate a radiating patch, integrated matching section and band pass filter.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.660-668
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• 2003

본 논문에서는 광대역 특성을 가지면서 소형화가 용이한 다중 미앤더 스트립 모노폴 안테나 구조를 제안하였다. 제안한 안테나 구조는 스트립으로 이루어진 수직한 모노폴 안테나를 미앤더 형태로 구부림으로써 안테나 높이를 감소시킬 수 있으며, 구부리는 회수가 증가할수록 대역폭이 늘어나는 특성을 갖는다. 제안한 다중 미앤더 스트립 모노폴 안테나 구조로부터 최근 주목을 받고 있는 UWB 롱신 대역폭을 포함하는 2.9 GHz에서 10.85 GHz까지의 넓은 대역폭과 전방향에 대한 최대/최소 복사이득의 차가 0.1 dBi 이내인 우수한 모노폴 안테나 복사패턴을 갖는 크기 $14 mm{\times}14 mm{\times}14mm$의 광대역/소형 안테나를 설계하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.7
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• pp.1094-1101
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• 2001

The design of a compact folded patch antenna with moderately broad bandwidth is presented in this paper. The proposed antenna has radiation characteristics that are similar to the conventional monopole antenna. However, since this antenna is designed in a planar form, it has smaller size than that of a conventional monopole antenna. We have investigated the resonance frequency and bandwidth characteristics of the proposed antenna by changing the antenna design parameters. The proposed planar form of a monopole antenna in this paper has 1.17 GHz bandwidth with a matching circuit at the center frequency of 6.05 GHz.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.266-269
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• 2003

마이크로파 대역에서 넓은 공진 주파수 대역폭을 갖는 V 형 테이퍼드 슬롯 안테나와 1x4 선형 배열 안테나를 설계하였다. 설계주파수는 5.8 [GHz]이었고 비유 전율이 3.48 인 RO4350 기판을 사용하였으며 멀티옥타브 특성과 복사 패턴을 얻었다.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.1
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• pp.177-187
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• 2001

It is important to test and evaluate the variation degree of ship-mounted antenna radiated power with respect to all directions in order to use more effectively antennas that installed on naval ships. The naval ship has various sensors for navigation, communication and electronic warfare, etc. And the performance of these sensors extremely depends on the various characteristics of antenna system to transmit and receive electromagnetic wave. The radiated power pattern of the antenna differs from all aspect angles of the ship because of complex superstructures. It is important to know the weak point(direction) of antenna radiation for appropriate operation. Therefore, the ARP(Antenna Radiation Pattern) of shipboard antennas is measured for the all aspect angles. The results of ARP measurement are utilized as reference for antenna arrangement of newly-built same class warship. This study also describes the development results for the ARP measurement technique, software design and test procedures to measure the radiation pattern of communication equipment antennas using the fixed test site.