• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.43-55
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• 2013

In this paper, we propose a cylindrical active phased array antenna of Beam Steering Characteristics in the horizontal plane(H-plane) and vertical plane(E-Plane) on the cylinder form array structure. We design the bent dipole antenna of the cylindrical array structure adapted excellent mutual-coupling characteristics, designed and manufactured the cylindrical array antennas and power combiner/divider unit for power dividing and combining on the antenna. The radiating elements array spacing of Cylindrical array antenna were determined to avoid grating lobes at half power beam steering. Beam steering of the antenna was implemented with 6-bit phase shifter in the transceiver and have been designed based on the characteristics the antenna beam steering at -24 degrees to 24 degrees horizontal, vertical 0 degrees to 36 degrees beam steering. A cylindrical active phased array antenna that produced for verification the performance of the antenna are measured radiation characteristics in accordance with beam steering at L-Band.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.3
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• pp.433-438
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• 2017

Containing an Angle-of-Arrival(: AOA) estimation and interference suppression techniques, an adaptive beamformer is one of core techniques for the Signal Intelligence(: SIGINT) which collect various intelligence utilizing cutting edge devices including the radar and satellite. It generates a beam with the directivity in a corresponding direction, to efficiently receive a signal from the specific direction, using antenna array. In this paper, we present the received signal model including interference signals and noise, which can be applied to an input of the signal intelligence satellite system equipped with the AOA estimation and the interference cancellation techniques, and analysis the characteristics of various signals, which can be included in the proposed received signal model. This proposed signal model can be directly applied to the performance evaluation for a variety of beamforming techniques. Also, we verify the spectrum characteristic of the presented received signal model in the frequency domain through computer simulation examples.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.5
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• pp.949-958
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• 2018

A voice recognition control system is a system for controlling a peripheral device by recognizing a voice. Recently, a voice recognition control system have been applied not only to smart devices but also to various environments ranging from IoT(: Internet of Things), robots, and vehicles. In such a voice recognition control system, the recognition rate is lowered due to the ambient noise in addition to the voice of the user. In this paper, we propose a dual channel acoustic beamforming hardware architecture for MEMS(: Microelectromechanical Systems) microphones to eliminate ambient noise in addition to user's voice. And the proposed hardware architecture is designed as ASIC(: Application-Specific Integrated Circuit) using TowerJazz $0.18{\mu}m$ CMOS(: Complementary Metal-Oxide Semiconductor) technology. The designed dual channel acoustic beamforming ASIC has a die size of $48mm^2$, and the directivity index of the user's voice were measured to be 4.233㏈.

• Journal of the Korea Society for Simulation
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• v.28 no.2
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• pp.139-147
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• 2019

A MANPADS(Man Portable Air Defense System), which tracks infrared energy, is light enough for individuals to carry and can against to a variety of aircraft, making it widely deployed around the world, posing a major threat to aircraft. A flare has been developed as an IRCM(Infrared Countermeasures) that protects the life of friendly aircraft and combatants by deceiving such guided missiles. However, DIRCM, which can overcome the problems of existing IRCM, is being developed mainly in some developed countries, and the need for it has been increasing gradually. This paper modeled first generation IR seeker of AM modulation method, the second generation IR seeker of FM modulation method, and the third generation IR seeker of pulse modulation method among various MANPADS, and modeled the scattering light phenomenon in the seeker when laser beams are investigated in DIRCM. Using this, jamming simulations were performed in various engagement environments of the MANPADS and aircraft equipped with DIRCM, and the miss distance of the guided missiles and aircraft were analyzed. Simulation results show that DIRCM, which irradiates a modulated laser beam with one jamming code, deceives both first, second and third generation MANPADS at 1km and 2km of engagement distance. In particular, the survival rate of aircraft equipped with DIRCM increased when the distance of engagement increased from 1km to 2km, and the survival rate was at least 99% at 2km of engagement distance.

• Journal of the Korea Institute of Military Science and Technology
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• v.5 no.2
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• pp.169-184
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• 2002

In order to extract bearing information from the directional sensors of DIFAR(directional frequency analysis and recording) that is a kind of passive sonobuoy, the cardioid beamforming algorithm applicable to DIFAR system was studied in the frequency domain. the algorithm uses narrow-band signals propagated though the media from the acoustic sources such as ship machineries. The proposed algorithm is expected to give signal to noise ratio of 6dB when it uses the maximum response axis(MRA) among the Cardioid beams. The estimated bearings agree very well with those from GPS data. Assuming the bearings from GPS data to be real values, the estimation errors are analyzed statistically. The histogram of estimation errors in each frequency have Gaussian shape, the mean and standard deviation dropping in the ranges -1.1~$6.7^{\circ}$ and 13.3~$43.6^{\circ}$, respectively. Estimation errors are caused by SMR degradation due to propagation loss between the source and receiver, daily fluctuating geo-magnetic fields, and non-stationary background noises. If multiple DIFAR systems are employed, in addition to bearing, range information could be estimated and finally localization or tracking of a target is possible.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.5
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• pp.413-420
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• 2009

We propose a novel feed network for a $2{\times}2$ array antenna to form a sectoral conical beam. The proposed feed network, which is a symmetrical structure, consists of four $90^{\circ}$ hybrids, a crossover, and four $90^{\circ}$ delay lines. To verify the performance of the feed network a $2{\times}2$ array antenna and the feed network are fabricated on a microstrip structure, and the radiation patterns are measured at the center frequency of 2.57 GHz. The maximum radiation is measured at the $45^{\circ}$ elevation angle and at the $45^{\circ}$, $135^{\circ}$, $225^{\circ}$, and $315^{\circ}$ azimuth angles depending on the choice of the input port of the feed network.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.8
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• pp.710-717
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• 2015

In this paper, we design an array antenna structure based on a patch ESPAR(Electronically Steerable Parasitic Array Radiator) antenna with three elements for reliable communication in high-speed railway wireless communication. The ESPAR antenna consists of the active element with a single RF-chain and the parasitic elements surrounding an active element. The ESPAR antenna is capable of beamforming by adjusting the reactance of the parasitic element. We propose a vertical array antenna structure based on the patch ESPAR antenna and simulate it according to the change of the number of antennas and the distance between antenna rows. The simulation results show that we can get the maximum beam gain and highest directivity when the distance between antenna rows is ${\lambda}$.

• 전기의세계
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• v.24 no.2
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• pp.22-24
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• 1975

안테나, 전파전파에 관한 학회에서의 발표논문중 전체의 약 반수가 안테나에 직접 관계한 것이며 약 1/4이 전파전파에 관한 연구이고 나머지 약 1/4은 산란, 회절, 잡음, 기초이론, 수치계산이론등에 관한 것 및 전파응용에 관한 것으로 되고 있다. 또 안테나에 대한 연구논문중 가장 많은 것이 phased array 안테나에 관한 것으로서 대형레이더, 항공기용 레이다 등에의 응용 기타 다목적의 빔 안테나에 이용될 것을 전제로 연구되고 있다. 많은 안테나 소자를 어떻게 배열하여서 어떠한 진폭과 위상으로 급전하면 최량의 지항성 또는 바라는 지향성이 얻어지며 또 그 오차는 얼마가 되는가 등이 연구의 중심과제가 되고 있다. 참고로 1974년 미국 조지아 공과대학에서 개최된 안테나 전파국제학술회의에서 발표된 제목들을 알아보면 표1과 같으며 phased array 안테나가 기초적 검토 단계를 지나 실용화단계에 접어든 것을 직감할 수 있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.9B
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• pp.1189-1195
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• 2001

본 연구에서는 수평면에 대해서 양방향성을 갖고 접지면을 향해서 주빔이 25$^{\circ}$의 기울기로 지향하도록 설계된 대칭 SSAIP(Strip, Air, Inverted Patch) 구조의 슬롯 결합 back-to-back 마이크로스트립 위생배열 안테나를 설계, 제작하였다. 이 구조의 안테나는 2-섹터 셀 사이트에서 기지국 또는 중계기의 지향성 안테나에 적용할 수 있으며, 도로 환경에 따라 지향각 25$^{\circ}$를 기준으로 약 $\pm$$10^{\circ}$정도 빔을 틸트할 수 있도록 위상기와 결합된다. 안테나는 공동모델을 이용하여 해석하고 앙상블로 설계한다. IMT-2000의 상.하향 링크 주파수 범위인 1.885~2.2GHz에서 안테나를 측정한 결과 임피던스 대역폭은 약 21%이였으며, $\pm$37$^{\circ}$의 지향각 오차를 보였다.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.320-321
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• 2003

위성통신 및 무선통신에서 안테나의 수신 감도를 향상시키기 위한 노력은 계속되어 왔다. 안테나의 지향성을 높이기 위하여 다수의 동형 단위 안테나들을 일정 방향으로 배열하여 안테나를 기계적으로 회전시키지 않고, 고정된 다수의 동형 단위 안테나들에서 방사되는 전파의 위상을 전자적으로 변화시켜 방사 빔을 주사하는 방법, 즉 위상배열 안테나(Phased Array Antenna)를 널리 사용하고 있다. 위상배열 안테나의 단위 안테나에서 방사되는 전파의 위상을 변화시키기 위해선 실시간 시간지연 시스템이 필요하다. (중략)