• Journal of IKEEE
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• v.25 no.4
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• pp.703-709
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• 2021

As drone technology advances, the risks of drones are increasing, then technology to detect drones is becoming important. In this thesis, it was verified that miniaturized and lightweighted active array antenna could be used for radar system to detect drones in reality. The transmit-receive module was designed in the form of tile-type to simplify interconnections between devices. The waveform generation module and the down conversion module were miniaturized to include in one body too. As a result of verifing the detection performance through test, it was confirmed that the detection range was over 3.7Km.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.1
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• pp.46-52
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• 2010

A compact circular microstrip patch antenna with a switchable circular polarization(CP) is proposed at 2.4 GHz. An unequal cross-shaped slot on a ground plane is utilized as a perturbation. By switching pin diodes mounted on the slot, the CP sense of each antenna can be simply switched from left-handed(LH) CP to right-handed(RH) CP vice versa. Since the perturbation can be made on the ground plane and no bias circuit is required on the patch side, the bias circuit has not effect on the main beam radiation. From the experimental results, the impedance bandwidth and CP bandwidth of the proposed antenna have shown up to 150 MHz and 35 MHz, respectively. The peak gain of the proposed antenna is 1.7 dBi for both CP senses.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.449-452
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• 2018

In this paper, we design a Wibro / WiFi dual band microstrip antenna for wireless broadband communication. The proposed antenna is designed to have the characteristics of FR-4 (er = 4.3), size of $40[mm]{\times}40[mm]$, and usable in 2.31[GHz] and 5.8[GHz] bands of Wibro / WiFi. The simulation is performed by CST Microwave Studio 2014 The simulation result shows that the gain is 2.308[dB] at 2.31[GHz] and 2.985[dB] at 5.8[GHz]. S-parameters were also found to be less than -10[dB] (WSWR2: 1) in the desired frequency band, and a small number of parameters and a compact antenna were designed. It is expected that many users will use the mobile communication antenna for accurate and fast communication for smooth wireless broadband communication.

• 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.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.4
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• pp.763-770
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• 2021

In this paper, in order to exclude the influence of BAN(Body Area Network) signals operating in the ISM band, the design and optimization process of an on-body microstrip patch antenna operating at 4.567 GHz is presented. The antenna for the monitoring of the lower legs with cancellous osteoporosis is designed to be lightweight and compact with improved return loss and bandwidth. The structure around the applied lower leg consisted of a five-layer dielectric plane. Taking into account losses, the complex dielectric constant of each layer is calculated using multi Cole-Cole model parameters, whereas a unipolar model is used for normal or osteoporotic cancellous bones. The return loss of the coaxial feed antenna on the phantom is -67.26 dB at 4.567 GHz, and in the case of osteoporosis, at the same frequency the return loss difference is 35.88 dB, and the resonance frequency difference is about 7 MHz.

• Journal of electromagnetic engineering and science
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• v.19 no.1
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• pp.64-70
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• 2019

In this study, a compact series-fed center-fed open-stub (SFCFOS) linear array antenna for K-band applications is presented. The antenna is composed of a single-line 10-element linear array. A symmetrical Chebyshev amplitude distribution (CAD) is used to obtain a low sidelobe characteristic against a uniform amplitude distribution (UAD). The amplitude is controlled by varying the width of the microstrip patch elements, and open-ended stubs are arranged next to the last antenna element to use the energy of the radiating signal more effectively. We insert a series-fed stub between two patches and obtain a low mutual coupling for a 4.28-mm center-to-center spacing ($0.7{\lambda}$ at 21 GHz). A prototype of the antenna is fabricated and tested. The overall size of the uniform linear array is $7.04{\times}1.05{\times}0.0563{\lambda}_g^3$ and that of the Chebyshev linear array is $9.92{\times}1.48{\times}0.0793{\lambda}_g^3$. The UAD array yields a ${\mid}S_{11}{\mid}$ < -10 dB bandwidth of 1.33% (20.912-21.192 GHz) and 1.45% (20.89-21.196 GHz) for the CAD. The uniform array design gives a -23 dB return loss, and the Chebyshev array achieves a -30.68 dB return loss at the center frequency with gains of 15.3 dBi and 17 dBi, respectively. The simulated and measured results are in good agreement.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.576-579
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• 2007

마이크로스트립으로 급전되는 슬롯 안테나를 소형화하기 위해 폴디드 슬롯과 T형 마이크로스트립 선로로 구성된 안테나 구조를 제안하였다. 전형적인 마이크로스트립으로 급전된 슬롯 안테나와 성능(안테나 크기, 슬롯 길이, 대역폭 등)을 비교하였으며, T형 마이크로스트립선로를 이용한 급전선로의 임피던스정합 방법에 대하여 설명하였다. 제안된 구조로 유전제기판상에 2.45GHz 대역 WLAN용 안테나를 설계 및 제작하였으며 특성 실험(반사손실, 부사패턴)을 통해 연구의 타당성을 확인하였다.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.219-222
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• 2002

본 논문에서는 이중 대역 소형 평면 패치 안테나를 이용하여 5.6GHz 대역과 5.8GHz 대역에서 동작하는 이중 대역 안테나를 제안하였다. 안테나의 격리도 특성을 최소화하기 위해 서로 다른 급전선 구조를 이용하였고, 급전부에 개방스터브를 사용하여 VSWR $\leq$2를 기준으로 5.48 GHz 대역과 5.87 GHz대역에서 각각 3.1%와 2.73% 이상의 대역폭을 얻었으며, 격리도 특성은 두 대역에서 평균적으로 -27㏈를 얻었다

• Proceedings of the KAIS Fall Conference
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• 2003.06a
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• pp.298-300
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• 2003

미국 PCS 대역 실내 간이 중계기에 사용될 수 있는 소형 안테나를 개발 제작하였다. 이동통신용 PCS 주파수는 CDMA에 비해 2배 정도 높기 때문에 건물 등 실내에서 통신하기에는 감쇠가 심하다. 따라서 건물 밖 신호를 받아서 건물의 특정부분으로 중계해주는 시스템이 필요하게 된다. 이 연구에서는 벽걸이 혹은 사진액자 형태의 중계기에 사용될 수 있는 소형이면서도 대역특성이 넓은 패치 안테나를 제작하였다. A4 크기의 중계기에 적용되는 소형 패치 안테나를 2개 배열하여 측정한 결과 S11의 -10㏈ 대역폭은 1.7 - 2.1㎓로 400㎒ 의 광대역이고, 이득 6 - 8.5㏈i 및 -l8㏈의 F/B 비 특성을 보였다.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1163-1168
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• 2008

Automatic Train Protection(ATP) System is developed by ETCS(European Train Control System) CONSORTIUM for unify Europe railway system. ATP system is composed of Eurobalise and EuroATC. Nowadays, Korea construct ATP system in conventional line and new electrical locomotives also install ATP system. It is important to verify quality which form checklist during Factory Acceptance Test at beyond the seas. In this paper, review the process, test item, norm and checklist for the Balise Transmission Module, Compact Antenna Unit, Vehicle Control Unit and Communication Controller at the Plymouth Bombardier and Vasteras enics factory.