• 한국항해학회지
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• 제20권3호
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• pp.97-105
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• 1996

Authors have studied characteristics evalution on semianechoic chamber. And authors also find that in case of low frequencies like from 30MHz to 100MHz there are big differencies between the calculated and the measured site attenuation in semianechoic chamber made with ferrite grid. This is on account of not being considered the mutual coupling effects between two antennas. Accordingly Authors calculated site attenuation due to mutual coupling effects and compared the measured site attenuation with the calculated site attenuation with mutual coupling correction. As a result good agreement between site attenuation, measured or calculated is obtained.

• 전기학회논문지
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• 제57권11호
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• pp.2127-2130
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• 2008

In this paper, a tunable bandpass filter with mutual inductive coupling circuits is newly designed and demonstrated for UHF TV tuner ranged from Ch.14(473MHz) to Ch.69(803MHz) applications. Conventional HF tuning circuit with an electromagnetic bandpass filter has several problems such as large size, high volume and high cost, since the electromagnetic filter is comprised of several passive components and air core inductors to be assembled and controlled manually. To address these obstacles, peaking chip inductor was newly applied for constructing the mutual inductive coupling circuit. The proposed circuit was newly and optimally designed, since the chip inductor showed lower components Q-value than the air core inductor. A varactor diode has been also used to fabricate the proposed tunable bandpass filter for RF tuning circuit. The fabricated tunable filter exhibited low insertion loss of approximately -3dB, high return loss of below -10dB, and large tuning bandwidth of 330MHz.

• Journal of electromagnetic engineering and science
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• 제5권3호
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• pp.122-125
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• 2005

This paper describes a design of a miniature patch antenna and its 4-channle array for 5.25 GHz wireless LAN band. Each patch element is designed for the low mutual coupling between each element and for the small size of the array antenna. The size of the each element is $7 mm{\times}14.5 mm{\times}5.6 mm$ and it satisfy IEEE 802.11a frequency band. It is arrayed for independent 4-channel operation. The total size of the array antenna is $35.6 mm{\times}52.5 mm{\times}5.6 mm$. The measured reflection coefficients and the radiation patterns of the fabricated antennas show the reasonable agreements with prediction.

• Journal of electromagnetic engineering and science
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• 제12권4호
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• pp.254-259
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• 2012

This paper presents a closely spaced two-element folded-dipole-driven quasi-Yagi array with low mutual coupling between adjacent elements. The antenna utilizes a T-junction power divider as the feeding network, with an input impedance of $50{\Omega}$. A microstrip-stub is added to the ground plane in the middle of the two elements to improve the mutual coupling characteristics. The folded dipole driver is connected to a $50{\Omega}$ microstrip line via a broadband microstrip-to-coplanar stripline transition with a quarter radial stub. A mutual coupling of less than -22 dB is measured between two folded-dipole-driven quasi-Yagi antennas with a center-to-center spacing of 30 mm ($0.55{\lambda}_0$ at 5.5 GHz). The proposed quasi-Yagi array yields a measured bandwidth of 4.75~6.43 GHz for the -10 dB reflection coefficient and a gain of 6.14~7.12 dBi within the bandwidth range.

• 한국위성정보통신학회논문지
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• 제8권4호
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• pp.37-42
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• 2013

이 논문에서는 비이상적인 안테나 배열을 보상하는 방법과 안테나 배열을 이용하여 계산량 관점에서 효율적으로 도래각을 추정하는 방법을 제시하였다. 도래각을 추정하기 위해서는 안테나 배열을 주로 이용한다. 배열을 이루는 각 안테나 소자에 수신되는 신호의 위상차를 이용하여 도래각을 추정한다. 그러나 실제 안테나 배열의 경우 각 안테나 사이의 상호결합 때문에 각 안테나로부터 방사되는 전파의 빔 패턴이 변형되고 이로 인해 도래각 추정 성능이 저하된다. 제안 방식에서는 먼저 상호결합의 영향을 동일하게 받는 안테나 배열의 일부분인 부분배열을 이용하여 도래각을 추정한다. 도래각을 추정하기 위해서는 계산량 관점에서 효율적인 ESPRIT(estimation of signal parameters via rotational invariance techniques)알고리듬을 적용한다. 그 다음 추정한 도래각을 바탕으로 상호결합을 보상하고 부분배열의 크기를 본래의 배열 크기로 확장시킨다. 모의실험 결과 제안한 방법은 재밍대잡음비가 비교적 작을 때에도 우수한 성능을 나타내었다.

• 전기전자학회논문지
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• 제23권1호
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• pp.306-309
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• 2019

Wireless charging is a technology of transmitting power through an air gap to an electrical load for the purpose of energy dissemination. Compared to traditional charging with code, wireless power charging has many benefits of avoiding the hassle from connecting cables, rendering the design and fabrication of much smaller devices without the attachment of batteries, providing flexibility for devices, and enhancing energy efficiency, etc. A transmitting coil and a receiving coil for inductive coupling or magnetic resonant coupling methods are available for the near field techniques, but are not for the far field one. In this paper, the wireless power transfer (WPT) circuit by using magnetic resonant coupling method with a resonant frequency of 13.45 Mhz for the low power system is implemented to measure the power transmission efficiency in terms of mutual distance and omnidirectional angles of receiver.

• 한국전자파학회논문지
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• 제15권11호
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• pp.1108-1115
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• 2004

본 논문에서는 밀리피터파 대역의 응용에 적용될 수 있는 새로운 형태의 로트맨 렌즈를 제시하였다. 본 논문에서 새로이 제시하는 유전판 로트맨 렌즈는 도체손실과 포트간 상호간섭(mutual coupling)을 감소시킬 수 있는 특성을 지니고 있으며 밀리미터 대역에서 구현이 보다 용이한 구조이다. 기존의 렌즈가 도체 평판 구조인데 반해 제안된 렌즈는 유전판과 슬롯으로 구성되어 있으며 TE$_{0}$모드로 구동한다. 중심주파수 15 GHz에서 9개의 빔 포트와 9개의 배열포트로 구성된 렌즈를 9개의 TSA(Tapered Slot Antenna) 배열과 더불어 설계 및 제작하였다. 측정결과에 따르면 빔폭은 13 GHz에서 약 15$^{\circ}$이며 효율은 약 34 %를 나타냈으며 포트간 상호간섭은 주파수가 상승함에 따라 점진적으로 감소함을 관찰할 수 있었다. 밀리미터 파 대 역에서 제작 및 측정 장비의 부족으로 인해 설계주파수를 15 GHz로 크게 낮추었음에도 불구하고 효율은 평행 도체판 구조의 렌즈와 대등한 값을 얻었다. 향후 밀리미터파 대역에서 고유전율 막(high dielectric thin film) 형태로 제작된다면 도체 손실파 상호간섭을 크게 감소시킬 것이 기대된다.

• 한국통신학회논문지
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• 제37C권12호
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• pp.1296-1302
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• 2012

본 논문에서는 유전 알고리즘(genetic algorithm)을 이용하여 이중대역 다이폴 배열(dipole array) 안테나의 설계 및 최적화 문제에 대해서 고찰하였다. 다이폴로 구성된 이중대역, 개구면 공유형 선형 배열은 4 GHz와 9.5 GHz에서 동작하도록 설계하였다. 또한, 다이폴의 전류 분포는 모멘트 기법(method of moment)을 이용하여 계산되었으며, 계산 과정에서 다이폴 간 상호 결합(mutual coupling)을 고려하였다. 두 공진 주파수 대역에서 낮은 부엽 준위를 도출하기 위해서 비주기 다이폴 배열 설계에 유전 알고리즘을 적용하였고, 최적 설계된 이중대역 다이폴 배열 안테나는 4 GHz와 9.5 GHz에서 각각 -15.7 dB, -17 dB로 낮은 PSL 특성을 나타내었다. 또한, 이 결과를 상용 시뮬레이션 결과와 비교 분석하였다.

• Journal of electromagnetic engineering and science
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• 제16권3호
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• pp.194-197
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• 2016

An eight-element compact low-profile multi-input multi-output (MIMO) antenna is proposed for wireless local area network (WLAN) mobile applications. The proposed antenna consists of eight inverted-F antennas with an isolation-enhanced structure. By inserting the isolation-enhanced structure between the antenna elements, the slot and capacitor pair generates additional resonant frequency and decreases mutual coupling between the antenna elements. The overall size of the proposed antenna is only $33mm{\times}33mm$, which is integrated into an area of just $0.5{\lambda}{\times}0.5{\lambda}$. The proposed antenna meets 5-GHz WLAN standards with an operation bandwidth of 4.86 - 5.27 GHz and achieves an isolation of approximately 30 dB at 5 GHz. The simulated and measured results for the proposed antenna are presented and compared.

• 한국전기전자재료학회논문지
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• 제20권10호
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• pp.873-877
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• 2007

In order to apply a complex multilayer chip LC filter, this study has estimated the interfacial reaction and coupling properties of dielectric materials $Pb(Fe_{1/2}Nb_{1/2})O_3$ and Ni-Zn-Cu ferrite materials through low-temperature co-sintering (LTCS). PFN powders were fabricated using double calcinated at $700^{\circ}C$ and then $850^{\circ}C$. While the perovskite phase rate was found to be 91 %, after heat treatment at $900^{\circ}C$ for 6h, the perovskite phase rate and density exhibited a value of 100 % and 7.46$g/cm^3$, respectively. The PFN/Ni-Zn-Cu ferrite, PFN/CUO (or $Pb_2Fe_2O_5$) and ferrite/CuO (or $Pb_2Fe_2O_5$) were mechanically coupled through interfacial reactions after the specimen was co-sintered at $900^{\circ}C$ for 6 h. No intermediate layer exists for the mutual coupling reaction. This result indicates the possibility of low-temperature co-sintering without any interfacial reaction layer for a multilayer chip LC filter.