일차원과 이차원 Ka-대역 프린티드 다이폴 배열 안테나의 스캔 블라인드니스 분석

구한이,송성찬,남상욱 한국전자파학회 2019 한국전자파학회논문지 Vol.30 No.3

In this study, an active element pattern (AEP) of a printed dipole was analyzed in 1D and 2D arrays. First, an AEP of the printed dipole was obtained using the simulation in the 2D infinite array. The scan blindness in the 2D array occurred in the E-plane direction at around ±36°; however, it was barely observed in the 1D array. To analyze the cause of the scan blindness in the 2D array, the dispersion properties of a unit cell was obtained and compared with the scan blindness by frequency change. The difference between the scan blindness of the 1D and 2D arrays was clarified using the comparison of the Q value in the unit cell in the 1D and 2D arrays. Then, the coupling of the electric field in the E-plane direction was observed when nine elements were separated between the two ports in a linearly arranged dipole structure. Finally, the printed dipole array was fabricated, and an AEP was measured for the 11×1 and 11×3 sub arrays. The proposed theory was verified using these observations and by comparison with the simulation results.

국내 맥상광체조사를 위한 3차원 전기비저항 모델링자료의 3차원 역산 해석

이호용,정현기,정우돈,곽나은,이효선,민동주 한국지구과학회 2009 한국지구과학회지 Vol.30 No.6

최근 들어 국내 광산개발에 대한 관심이 고조되면서 새로운 광상탐사 및 기존 광상의 연장성 확인 등의 목적으 로 물리탐사를 적용하는 사례가 늘고 있다. 금속광상 탐사의 경우, 광화대가 주변에 비해 높은 전기전도도를 갖기 때문 에 이를 탐지하기 위하여 전기비저항 탐사를 수행하는 것이 일반적이며, 현실 여건상 대부분 2차원 탐사가 수행된다. 그러나 국내 금속광상의 대부분이 맥상으로 분포하고 있으며, 광맥의 폭이 변한다거나 광맥이 단층에 의해 끊어져 있는 등 매우 복잡한 3차원 구조를 띤다. 따라서 3차원 광체구조에 대하여 2차원 탐사 및 2차원 해석을 수행할 경우 왜곡된 해석을 초래할 수 있다. 이에 이 연구에서는 이러한 3차원 광체구조에 대한 3차원 전기비저항 탐사의 적용성을 검토하 기 위해 주향에 수직한 여러 측선에 대하여 2차원 쌍극자-쌍극자 탐사를 수행하여 얻은 자료와 3차원 단극자-단극자 배열을 이용하여 얻은 자료들을 각각 3차원 역산한 후 이들을 2차원 해석결과와 비교하였다. 3차원 맥상광체로는 맥폭 이 변하는 모형과 맥이 단층에 의해 어긋난 모형 등을 가정하였다. 2차원 쌍극자-쌍극자 배열자료에 대해 3차원 역산을 수행하여 얻은 결과를 3차원 단극자-단극자 배열자료와 비교하면 단극자-단극자 탐사자료가 전체적인 구조는 잘 보여주 나 배열의 특성상 쌍극자-쌍극자 탐사자료만큼 정확한 결과를 제시하지 못함을 확인할 수 있었다. 따라서 실제 탐사시 주향의 방향에 대한 정보를 알 수 있다면 주향에 수직한 2차원 측선들에 대해 쌍극자-쌍극자 탐사를 수행하고 이를 3 차원 해석하는 것이 가장 바람직하다. 그러나 지표면에 광체가 드러나 있는 경우에 대해서는 이미 개발이 완료된 상태 이며, 현재 남아있는 광상은 지하 깊은 곳에 매몰되어 있는 경우가 대부분이다. 이러한 경우 주향에 대한 정보를 알기 어려우므로 비록 해상도는 떨어지더라도 3차원 단극자-단극자 탐사를 수행하고 해석하는 것이 바람직할 것으로 보인다. Recently as the interest in the development of domestic ore deposits has increased, we can easily find some studies on exploration geophysics-based ore-deposit survey in literature. Based on the fact that mineralized zone are generally more conductive than surrounding media, electrical resistivity survey among several geophysical surveys has been applied to investigate metallic ore deposits. Most of them are grounded on 2-D survey. However, 2-D inversion may lead to some misinterpretation for 3-D geological structures. In this study, we investigate the feasibility of the 3-D electrical resistivity survey to 3-D vein-type ore deposits. We first simulate 2-D dipole-dipole survey data for survey lines normal to the strike and 3-D pole-pole survey data, and then perform 3-D inversion. For 3-D ore-body structures, we assume a width-varying dyke, a wedge-shaped, and a fault model. The 3-D inversion results are compared to 2-D inversion results. By comparing 3-D inversion results for 2-D dipole-dipole survey data to 3-D inversion results for 3-D pole-pole survey data, we could note that the 2-D dipole-dipole survey data yield better inversion results than the 3-D pole-pole data, which is due to the main characteristic of the pole-pole array. From these results, we are convinced that if we have certain information on the direction of the strike, it would be desirable to apply 2-D dipole-diple survey for the survey lines normal to the strike. However, in most cases, we do not have any information on the direction of the strike, because we already developed the ore deposit with the outcrops and the remaining ore deposits are buried under the surface. In that case, performing 3-D pole-pole electrical resistivity survey would be a reasonable choice to obtain more accurate interpretation on ore body structure in spite of low resolution of pole-pole array.

Excitation Energy Migration in Multiporphyrin Arrays

황인욱,Atsuhiro Osuka*,김동호,Naoki Aratani 대한화학회 2005 Bulletin of the Korean Chemical Society Vol.26 No.1

During the last decade, the exploration of nanoscale device and circuitry based on molecules has gained increasing interest. In parallel with this, considerable effort is being devoted to the development of molecular photonic/electronic materials based on various porphyrin arrays. This involves light as an input/output signal and excitation energy migration as a mechanism for signal transmission. Absorption of a photon at the light collector end of the porphyrin array yields the excited state, which migrates among the intervening pigments until reaching the emitter, whereupon another photon is emitted. As a consequence, it is relevant to understand the excitation energy transfer (EET) processes occurring in various forms of porphyrin arrays for the applications as artificial light harvesting arrays and molecular photonic/electronic wires. Since the excitonic (dipole) and electronic (conjugation) couplings between the adjacent porphyrin moieties in porphyrin arrays govern the EET processes, we have characterized the EET rates of various forms of multiporphyrin arrays (linear, cyclic, and box) based on various time-resolved spectroscopic measurements. We believe that our observations provide a platform for further development of molecular photonic/electronic materials based on porphyrin arrays.

Excitation Energy Migration in Multiporphyrin Arrays

Hwang, In-Wook,Aratani, Naoki,Osuka, Atsuhiro,Kim, Dong-Ho Korean Chemical Society 2005 Bulletin of the Korean Chemical Society Vol.26 No.1

During the last decade, the exploration of nanoscale device and circuitry based on molecules has gained increasing interest. In parallel with this, considerable effort is being devoted to the development of molecular photonic/electronic materials based on various porphyrin arrays. This involves light as an input/output signal and excitation energy migration as a mechanism for signal transmission. Absorption of a photon at the light collector end of the porphyrin array yields the excited state, which migrates among the intervening pigments until reaching the emitter, whereupon another photon is emitted. As a consequence, it is relevant to understand the excitation energy transfer (EET) processes occurring in various forms of porphyrin arrays for the applications as artificial light harvesting arrays and molecular photonic/electronic wires. Since the excitonic (dipole) and electronic (conjugation) couplings between the adjacent porphyrin moieties in porphyrin arrays govern the EET processes, we have characterized the EET rates of various forms of multiporphyrin arrays (linear, cyclic, and box) based on various time-resolved spectroscopic measurements. We believe that our observations provide a platform for further development of molecular photonic/electronic materials based on porphyrin arrays.

A Circularly Polarized Waveguide Narrow-wall Slot Array using a Single Layer Polarization Converter

Kim, Dong-Chul,Min, Kyeong-Sik The Korea Institute of Information and Commucation 2000 한국정보통신학회논문지 Vol.4 No.1

This paper describes the characteristics of a one dimensional narrow-wall slotted waveguide array with a single-layer linear-to-circular polarization converter consisting of a dipole array. An external boundary value Problem of one slot and three dipoles, which approximates the mutual coupling between the dipole array and an edge slot extending over three faces of a rectangular waveguide, is formulated and analyzed by the method of moments; design of polarization conversion is conducted for this model as a unit element. If every unit element has perfect circular polarization, grating lobes appear in the array pattern due to the alternating slot angle: these are suppressed in this paper by changing the dipole angle and degrading the axial ratio of the unit element. The validity of the design is confirmed by the measurements. The dipole array has negligible effects upon slot impedance; the polarization conversion for existing narrow-wall slotted arrays is realized by add-on dipole array.

Design of a Broadband Coupled-Fed Printed Dipole Antenna as an Array Element for Direction Finding Systems

Sungsik Wang,Sungjun Yoo,Junsik Park,Hongsuk Shim,Hosung Choo 한국전자파학회JEES 2019 Journal of Electromagnetic Engineering and Science Vol.19 No.4

This article proposes the design of a coupled-fed printed dipole antenna for direction finding (DF) systems. The antenna consists of a radiating 50 angled expanded-arm printed dipole as well as a fan-shaped feeder that is located on the opposite side of the radiating dipole. The 50 angled expanded-arm structure results in a wide beam-width and broadband-matching characteristics. The more the arm angle is bent, the wider the beam-width pattern. Note that the expanded structure to the side of the dipole arm allows the wide beam-width of the radiation pattern. The printed dipole is then electromagnetically coupled with the fan-shaped feeder to obtain broadband-matching characteristics. To obtain additional broadband-matching characteristics, the circular cavity and the four-step tapered structures of the radiating printed dipole are carefully tuned by considering the coupled fields induced by the indirect feeding structure. The reflection coefficients are −14.6 ㏈ and −11.9 ㏈ at 1.575 ㎓ and 2.4 ㎓, and the boresight gains are 4.8 ㏈i and 1 ㏈i, respectively. To confirm the DF capability of the proposed antenna, the pattern of the 4×4 arrays is observed by varying the steering angle.

5G 단말기용 이중대역 평면 다이폴-스트립 배열 안테나 설계

정봉식(Bongsik Jeong) 한국정보기술학회 2022 한국정보기술학회논문지 Vol.20 No.2

In this paper, a dual-band 4x1 dipole-strip array antenna operated at 28㎓ and 39㎓ is designed to be applied to antenna-in-package(AiP). The dipole antenna is fed by a microstrip line and the strip is fed by a coupling with the dipole. Two poles of the dipole antenna are arranged separately on both sides of the substrate to utilize the line feed; one pole is on the ground plane, and the other pole is located on the other side of the substrate. As the phase difference between the neighboring ports of the array antenna changes, the gain and beam steering angle of the array antenna change. When the phase difference is changed to 0~135˚, the gain at 28㎓ and 39㎓ changes to 8.9~8.2㏈ and 10.2~9.4㏈, respectively, and the beam steering angle changes to 0~39˚ and 0~30˚, respectively. The designed array antenna has a thin thickness of 24.5㎜×3.34㎜×0.324㎜ in size and –10㏈ bandwidth of 26.6~29.7㎓ and 37.6~40.3㎓ in both bands, which has a bandwidth of about 3㎓.

X밴드용 다이폴 급전 평면배열 안테나 설계 및 제작

문성익,양두영,Mun, Seong-Ik,Yang, Du-Yeong 대한전자공학회 2002 電子工學會論文誌-TC (Telecommunications) Vol.39 No.5

본 논문에서는 기존외 야기-우다 안테나 배열이론을 마이크로스트립 안테나에 접목시킨 X밴드용 다이폴 급전 평면배열 안테나를 설계하고 제작하였다. 그리고 넓은 대역폭을 갖는 무선통신 시스팀에 쉽게 적용시킬수 있는 다이폴 급전 평면배열 안테나의 설계 절차에 대하여 기술하였다. 또한 FDTD 수치해석법을 이용하여 안테나의 복사특성, 반사손실과 대역폭을 개선시켰으며 제작을 통해 평면형 안테나 해석의 타당성을 입증하였다. 제작한 결과, 10GHz의 중심주파수에서 안테나의 이득은 4.9dBi이고 대역폭은 약 40%, 전후방비는 16dB, E면과 H면의 반 전력 빔폭은 각각 117°와 156°이다. VSWR<2를 기준으로 했을 때, 7.4GHz∼11.88GHZ의 주파수 범위에서 측정결과와 이론적인 결과가 비교적 잘 일치하였다. In this paper, the dipole-fed planar array antenna applied Yagi-Uda antenna away theory to microstrip antenna is designed and fabricated at X-band. The design procedure of the dipole-fed planar array antenna with the wide bandwidth is presented to be easily practiced to a wireless communication system. The radiation pattern, return loss and bandwidth of the antenna are improved by the finite differential time domain(FDTD) numerical method. The propriety of analysis of planar dipole antenna is proved from the measured data. From the measured results, the antenna maximum gain is 4.9dBi at center frequency of 10GHz and frequency bandwidth is about 40%. Front-to-back ratio is 16dB, and half-power beam-width of E-plane and H-plane are 117$^{\circ}$and 156$^{\circ}$, respectively. When VSWR of antenna is less than 2, the measured results are agreed well with the theoretical values in the frequency range from 7.4GHz to 11.88GHz.

5G용 이중대역 이중편파 배열안테나 설계

최종호(Jongho Choi),정봉식(Bongsik Jeong) 한국정보기술학회 2024 한국정보기술학회논문지 Vol.22 No.2

In this paper, we designed a dual-band dual-polarized 4x1 array antenna operating at 28GHz and 39GHz bands. The dual band was implemented with a dipole and a parasitic strip, and the dual polarization was implemented by crossing two dipole-strip antennas and applying a phase difference to the two ports. Here, the parasitic strip acts as a director and the flat conductor acts as a reflector, which increases the gain of the antenna. The feed line used a U-shaped microstrip line with a dipole vertical conductor as a ground surface. The dual-band dual-polarized cross antenna was designed as a 4x1 array antenna in a linear array. At this time, when the phase difference between two ports of the cross antenna is –90°, the level difference with the cross-polarization became 15dB. When the phase difference between the array elements is changed from 0° to 135°, the maximum beam steering angles of 30° and 22.5° and the maximum gains of 13.6dB and 13.1dB in both bands was obtained. And the frequency bandwidth in the two bands was 5GHz and 3.5GHz, satisfying the bandwidth required for 5G service.

Computational Analysis of a Dual Loop Dipole Antenna and Its Interleaving Array for Improving Transceiver |B1|-field for MRI

Hyunwoo Song,Daniel Hernandez,Kyoung-Nam Kim 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.76 No.4

This article intends to present the electromagnetic (EM) insight of the operation of a double loop shaped dual loop dipole (DLD) antenna as a single-channel transceiver coil and in an array configuration of multi-channel transceiver coil, designed to provide high signal-to-noise ratio (SNR) by using numerical simulations for 300 MHz magnetic resonance imaging (MRI). Thus, this section includes the comparison of DLD antenna and commonly used loop coils through EM simulations. The use of a DLD antenna is proposed to address the length issue that traditional straight dipole have by making a spiral type in a loop style, while having the same effective physical length of the straight dipole. The magnetic flux density (|B1|)-fields of the DLD antenna and the traditional loop coil are compared by field maps acquired by EM simulations. In addition, the DLD antenna has been extended to a 7-channels array, for which the magnetic field coupling between each coil is analyzed and presented through the noise correlation matrix. The use of the DLD antenna exhibits higher |B1|-field intensity while keeping the similar uniformity than a surface loop coil. We use the DLD antenna 7-channel array to observe its utility as multi-channel with short distance overlap between elements; each element is approximately 37 mm away from neighboring element. Transceiver array arrangements also show improved coil performance, especially the interleaving configuration with loop coil indicates lowered mutual inductance coupling at calculated noise correlation matrix. The proposed DLD antenna is expected to induce rapid imaging and high |B1|-field, when expanded to multi-channel planar or volume configuration since it can maximize the number of configuring coil elements within limited imaging area leading effective parallel imaging and deeper penetration depth due to the traveling wave.