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Left-Handedness 특성 Metamaterial 구조의 마이크로파 부품과 안테나 개발에의 적용 기술
강승택 한국전자파학회 2009 전자파기술 Vol.20 No.2
본고를 통해 초고주파 이론과 공학 분야는 물론 물리학, 재료공학의 기초 학문 분야에서도 지대한 관심을 모으고 있는 Metamaterial(MTM) 구조에 대해 조명하고자 한다. 먼저 MTM의 핵심이라고 할 수 있는 Left-Handedness(LH) 왼손 전파 법칙과 LH 발생재질인 Double Negative(DNG) 재질에서의 전파 특성을 상대 유전율과 상대 투자율 평면에서 확인하고, 일반 매질인 Double Positive(DPS)형인 오른손 전파 법칙 Right-Handedness(=RH) 매질과의 결합(Composite Rightand Left-Hnaded=CRLH)에서 얻어지는 특징들을 살펴본다. 특히 DPS와 DNG의 결합에서 얻을 수 있는 음의 공진과 0차 공진(Zero-Order Resonance)을 언급하고 ZOR을 응용한 RF 부품의 소형화와 특성 개선사례를 소개한다. 또한, 안테나와 전자파 산란 특성에 MTM의 특수한 성질을 이용하여, 크기를 줄이거나 표면파를 억제하거나 혹은 방사 개구를 확대 또는 렌즈 특성을 얻어낸 사례도 언급된다. 그리고 LH 특성은 아니지만 MTM 계열인 ENG(Epsilon Negative), MNG(Mu Negative), ENZ(Epsilon Near Zero)를 응용한 예들을 보이고, MTM 관점에서 FSS(Frequency Selective Surface )의 특성을 논의하고, 그간에 발표된 대표적 MTM 연구 결과에 대한 소개를 마치고자 한다.
강승택,김형석 대한전기학회 2011 Journal of Electrical Engineering & Technology Vol.6 No.6
This paper investigates a method to tackle the resonance problems of the rectangular power-bus structure(PBS) using thin sheets loaded with periodic metal strips. The equivalent surface impedance of the proposed loading is calculated and involved in the expression of the impedance that accounts for in the PBS, in order to improve the resonance behavior of the original structure. The effects of the strips and the immediate surroundings are illustrated by a number of numerical experiments. Also the restrictions of the technique are addressed.
The Field of Power/Ground Planes influenced by the HPEM Source, and its Damage Reduction
강승택,김형석 대한전기학회 2012 Journal of Electrical Engineering & Technology Vol.7 No.3
This paper looks into the field inside the wide rectangular box structure that is excited by the High Power Electromagnetic(HPEM) source as a potential threat to electric grid and communication networks causing malfunction or destruction. The rectangular box is assumed power/ground planes and its internal field is calculated by the cavity model with the lightning strike excitation as an HPEM pulse. The accuracy of the calculation method employed here is validated through a 156mmX106mmX508μm parallel metallic plate case which is manufactured and tested, and is applied to the size of a building. With the help of the cavity model that takes into account loading,the level of the electric field is shown to decrease when a metal pillar is loaded between the power and ground planes.
An Orthogonally Polarized Negative Resonance CRLH Patch Antenna
강승택,전진수,박태준 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.1
A novel fully-printed microstrip antenna with negative first resonance and dualpolarization is proposed. The radiator is printed on the 1-layer substrate instead of multilayers. The -1stresonance results from a composite right- and left-handed(CRLH) structure that has a circumferentiallyinterlocked gap capacitively coupling a patch with a shorted-ring. This compact antenna is providedwith a dual-polarization capability by creating two orthogonal linear polarizations in one body withcoaxial feeds. The design is carried out by doing full-wave EM field simulation which is comparedwith the measurement of the fabricated antenna prototype. The measured results give the gain of 5 dBiand the efficiency of 78% at the -1st resonance mode as the center frequency of a downlink channel ofthe bandwidth over 20 MHz with 29 dB polarization isolation for mobile communication
스플라인형 분할차분 보간법을 이용한 다층구조 문제의 임피던스 행렬의 효율적 계산
강승택,최재훈 한국전자파학회 1999 한국전자파학회논문지 Vol.10 No.2
In this paper, a spline-type divided-difference interpolation technique is proposed to efficiently evaluate the impedance matrix elements in the MoM analysis of layered medium problems. This method is combined with the fast computational method of the basis-expanded and tested dyadic Green's functions (expressed in the spectral domain integrals) in a recent literature. For the sake of its validity, the proposed method is applied to analyze the characteristics of a microstrip gap discontinuity, a microstrip filter, and an aperture coupled patch antenna. Numerical results obtained by this approach are in good agreement with those of other approaches.
Evolution-strategy Optimized Dual-Band Antenna for UHF-band RFID/IoE Application
강승택,한다정,이창형 융복합지식학회 2016 융복합지식학회논문지 Vol.4 No.2
This paper presents an optimization-based design method for a multi-band antenna. From various optimization techniques, evolution strategy is adopted to find the proper initial geometry for creating the resonance at two frequencies(433 MHz and 900 MHz) with a limited physical size. The antenna structure is finalized by adjusting the geometrical parameters to meet the specifications of the UHF-band RFID/IoE services. The design method is validated by fabricating the antenna and testing its frequency responses which turn out compliant with the simulated results