• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.3
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• pp.229-238
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• 2016

In this paper, we have studied isolation enhancement using a suppression of surface wave to improve performance of array antenna. To reduce isolation between elements of array antenna, perfect magnetic conductor(PMC) and SOFT-surface is designed and located at center of ground plane, isolation and gain is simulated by commercial full wave simulator(HFSS). As a result, isolation of more than 40 dB and gain improvement of 2.2 dBi are obtained at E-plane array in case of both PMC and SOFT-surface. At H-plane array, air coupling is dominant compared to coupling by surface wave. It is conclude that this study is useful for design of compact array antenna and performance improvement of array antenna.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.34-38
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• 2002

기존에 제안된 도파관 스위치의 경우, 도파관의 E-plane에 PBG 기판을 내장하게 되는데, 이 경우 PBG 기판의 저항값을 조절해주는 MEMS 스위치의 바이어스 라인에 대한 문제점이 발생한다 본 논문에서는 PBG 기판을 도파관의 H-plane에 놓음으로써 바이어스 라인을 RF로부터 쉽게 분리하고, 또한 단일 공진 주파수를 갖는 PBG의 경우에 제한된 기판의 길이로 인하여 bandwidth가 좁아지는 문제점을 서로 다른 공진 주파수를 갖는 PBG 기판의 연결을 통해서 bandwidth를 약 80%이상 증가시킬 수 있음을 보였다.

• Proceedings of the KAIS Fall Conference
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• 2005.05a
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• pp.140-142
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• 2005

본 논문에서는 900MHz대역에서 전방향성 특성을 갖는 RFID tag용 다이폴 안테나를 설계하였다. 전방향성 특성을 얻기 위해 두 개의 다이폴 안테나를 대각으로 위치하고 $90^{\circ}$의 위상차를 주어 급전하였다. 시뮬레이션 툴을 이용한 결과 안테나의 이득은 1.78dB이었으며, E-plane 과 H-plane 모두 전방향성 특성을 보였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.863-867
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• 2007

In this paper, We have designed miniature microstrip patch antenna based on fractal structure using L-shaped feeding structure for 4G mobile communication applications. Miniature antenna has achieved by the presence of unusual fundamental resonant mode which we call "crossed-diagonal"(CD)current. Using CST Microwave Studio 5.0, patch antenna was designed. The simulated input return loss showed the bandwidth of 1.2647[GHz]($2.944{\sim}4.209GHz$), 35.4% below -10dB. The gain of E, H-plane was achieved 8.3dBi and 8.4dBi respectively. And beamwidth of 3dB in the E, H-plane was $40.6^{\circ}$ and $81.6^{\circ}$, respectively.

• Journal of the korean academy of Pediatric Dentistry
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• v.11 no.1
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• pp.7-12
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• 1984

This study was undertaker to observe the longitudinal change by orthodontic treatment for early Class III malocclusion in primary and mixed dentition. Cephalometric roentgenograms of 8 children with Class III malocclusion obtained during activator therapy were measured and compared with those obtained before activator therapy. The following results were observed. During treatment with activator; 1. The maxilla became retrueded in A,C,E, and K and protruded in F, G, H, and J. 2. The mandible became retruded in A,C,E, and F and F and protruded in H and J. No difference was observed in G and K. 3. Gonial angle became reduced in A,C,E,F, and K and increased in H. No difference was observed in G and J. 4. The steepness of mandibular plane became reduced in C,E,F,G,H, and J and increased in A. No difference was observed in K. 5. The inclination of upper incisor became more labially in A,C,E,G,H,J, and K. No difference was observed in F. 6. The inclination of lower incisor became more lingually in all cases.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.3
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• pp.257-267
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• 2015

This paper presents a ultra-wideband sinuous antenna that operates in a whole frequency range (0.824~5.85 GHz) of Cellular/GSM-800, GSM900, ISM, GPS, DCS/GSM1800, PCS/GSM1900, WCDMA/UMTS/IMT2000, WiBro, WLAN and WiMax. The proposed antenna, which is composed of two sinuous arms, is designed as a self-complementary structure in order to have frequency-independent characteristics. It also uses a wideband balun of Klopfenstein taper structure to match to $50{\Omega}$. Experimental results show that the -10 dB return loss bandwidth of the proposed antenna is 5.24 GHz that ranges from 0.76 to 6 GHz, which covers all the frequency bands of the various wireless services. Within the entire operating frequency range, the measured radiation patterns in both E-plane and H-plane show nearly constant bidirectional broadside beams and the maximum antenna gain is measured to fall between 2.32~6.01 dBi.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.5
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• pp.108-115
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• 2016

In this paper, the array synthesis horn antenna was designed and measured a radiation power after connecting magnetron. The proposed antenna was designed on the basis of the $4{\times}4$ array synthesis horn antenna characteristics. For suppressing a back-lobe, 2 step short-stub structures were attached to synthesis horn aperture upper and lower. The designed antenna has FBR(Front to Back Ratio) of 39.7 dB. HPBW(Half Power Beam Width) of the E-plane and the H-plane are $8.86^{\circ}$ and $7.35^{\circ}$ each in the measurement. For measuring a radiation power of array antenna that use a magnetron, the waveguide adaptor was designed and connected magnetron with horn antenna. Also, microstrip line coupler that replace a dielectric material with an air gap was designed for measuring a high power. As a result, average radiation output power of the $4{\times}4$ array synthesis horn antenna that connect a four magnetrons had a 0.063W.

• Journal of IKEEE
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• v.24 no.2
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• pp.372-377
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• 2020

This paper is based on the triangular inset patch antenna as the basic structure, and the array structure is the twin tree form to improve the antenna's main lobe gain and reduce the side lobe gain. A twin tree structure was implemented by placing two identical trees of 2-4-6 arrays of triangular inset patches side by side. The parametric analysis confirmed that the gap between tree structures arranged side by side is most effective for impedance matching. The fabricated antenna has a gain of 16.74 dBi at 24.15 GHz, and the beam width of the main lobe is 22° in the E-plane and 6° in the H-plane. The antenna size was 125 mm × 50 mm, and a Taconic TLC substrate with a dielectric constant of 3.2 was used. Although the main lobe gain is improved over the twin tree structure, The directivity in the beam pattern due to the mutual interference of the two tree array structure can be improved.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.9
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• pp.1058-1064
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• 2012

In this paper, an absorber based on metamaterial is proposed to improve the isolation of conventional WCDMA indoor repeater antenna. The proposed absorber is composed of Double Split Ring Resonators(DSRRs) and Complementary Spiral(CS) structure. The proposed absorber based on metamaterial is $9.6mm{\times}9.6mm{\times}1.2mm$ and absorption is about 94 % at 2.2875 GHz. The proposed antenna, which proposed absorber is applied to conventional WCDMA indoor repeater antenna, has isolation over 85 dB. Isolation is improved more than 10 dB compared with the conventional antenna. The VSWR is lower than 2 at WCDMA band from 1.92 GHz to 2.17 GHz. The radiation patterns are $60^{\circ}{\pm}10^{\circ}$ E-plane and H-plane, respectively. And, the gain is more than 6 dBi. The volume of proposed antenna with absorber based on metamaterial is $90mm{\times}90mm{\times}44.8mm$.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.2
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• pp.104-109
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• 2020

In this paper, we proposed a miniaturized folded inverted F antenna with ISM-band (center frequency : 447 MHz) for mounting in intelligent parking sensor. First, to mount the antenna in the intelligent parking sensor module (72 mm × 70 mm) with limited size, a folded inverted F antenna was designed at low frequency 447 MHz (wavelength λ : 670 mm) of the ISM-band. As a result, it resonates in the ISM band and obtains suitable characteristic with a -10 dB bandwidth of 13 MHz (2.9%). In addition, the H-plane pattern by the vertical and horizontal elements represents the omni-directional patterns from which the null point is removed, and the E-plane has directivity in a specific direction. Finally, it is suitable as and antenna for vehicle management in parking lots.