• Journal of Satellite, Information and Communications
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• v.11 no.4
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• pp.39-43
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• 2016

In this paper, we propose PID gain auto tuning method in steering type mobile robot. PID controller gain select method are various methods. Ziegler-Nichols step tuning method is one method tuning in PID controller. Use step tuning method find a the first gain and did experiment in steering mobile robot. and Make a new the second gains from the first gains. After appling the second gain in PID controller, Where perform observe for convergence time and stabilization error. Experiments result the second gain are useful in real steering mobile robot system.

• 한국정보통신설비학회:학술대회논문집
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• 2003.08a
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• pp.12-15
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• 2003

이동체 탑재형 안테나는 특성상 소형화 및 신호 추적 시간 단축이 중요한 요소이다. 이러한 특성은 위상변위기를 이용한 전자적인 빔 조향 방식으로 한층 더 보완할 수 있다. 현재 이동체에서 주로 사용되고 있는 DBS (Direct Broadcasting Satellite) 수신용 안테나는 패치 및 슬롯 형태의 안테나 소자를 배열하여 사용한다. 하지만 이러한 안테나 소자는 전방위각에 대해 인공위성 방향(앙각 45도)에서 이득 손실이 있기 때문에 위상변위기를 이용한 빔 조향 방식에서 사용하기에는 문제점을 가지고 있다. 따라서 모든 방위각에 대해 앙각 45도에서 최대 이득 특성을 갖는 안테나 소자를 이용해 이득 손실을 줄이는 것은 큰 의미가 있다. 본 논문에서는 monopole 주변에 PBG(Photonic Band Gap) 구조를 구현함으로써 표면파를 억제하여 앙각 45도 방향에서 최대 이득 특성을 보이는 안테나 소자를 제안한다.

• Journal of the Korean Society for Railway
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• v.5 no.1
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• pp.18-25
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• 2002

This paper is to study a comparison of ride stabilities for the guideway vehicle between its three primary steering types; the front-rear wheel steering type, tile independent wheel steering and the front wheel steering. A numerical model were built to investigate various factors to have an influence on the vehicular stability. It was shown that dynamic stabilities of the three types were dependent on the steering gain ratio of front wheel steering to rear. The front-rear wheel steering type was more stable for the value of positive steering gains and the shorter distance between front axle and guide link showed better stabilities. On the contrary, the independent wheel steering was more stable for the value of negative gains and the longer distance between front axle and guide link showed better stabilities. Ride characteristics of he front wheel steering seemed to be found midway. Ride behaviors due to time delay from front steering to rear were very different from steering type to type.

• Journal of Korea Society of Industrial Information Systems
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• v.15 no.2
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• pp.11-16
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• 2010

In this papar, we have proposed a small electronically steerable parasitic array radiator with 180 degree azimuth beam coverage and high gain characteristics. The proposed antenna is composed of a uniplanar Yagi dipole as a feeding element and two dipoles as parasitic elements. The fabricated antenna is tested by electronically changing the reactance loaded on the parasitic dipoles and the results show that it has 5.2dB~6.7dB gain in $-90^{\circ}{\sim}90^{\circ}$wide azimuth range and -10dB return loss characteristics within 5.725GHz~5.825GHz UNII band.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.1
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• pp.209-215
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• 2002

A study of the guideway vehicle was made for a comparison of ride stabilities between its two primary steering types; one is the front wheel steering and the other the front-rear wheel. A numerical model as a closed loop system was built for an investigation of various factors to have an influence on the vehicular critical speed which is closely associated with ridabilities. It was shown that dynamics stabilities of the front steering type was much better over a large value of steering gain and the longer distance between front axle and guide link for both types provided better stabilities as well. A large steering gain ratio of the front to the rear significantly plays an important role in an improvement of stability in the front-rear steering. To observe a qualitative trend on stability behaviors, the root locus was obtained by considering a time lag which may be frequently caused by the complicated steering mechanism. In performing so, the appropriate selection of steering gain had a greater effect on the front-rear steering vehicle far more ride comfort. In addition, the dynamics model proposed here can be utilized for a more accurate evaluation on the vehicle design in lateral or yawing absorber and moreover expanded for the analysis of independent four-wheel steering vehicle.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.8
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• pp.880-885
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• 2010

In this paper, we propose a reconfigurable beam steering antenna using a dipole and a loop. The radiation patterns of the two antennas were cancelled or compensated, and head for the specific direction when a dipole and a loop antenna are combined at the reasonable ratio. The structure of the antenna is very simple and planar. By changing on/ off states of switches, the proposed antenna can steer the beam direction in the x-y plane. Simulation results confirmed the steering characteristic by using two imaginary switches. The proposed antenna can change the direction of the maximum gain in the x-y plane($0^{\circ}$, ${\pm}50^{\circ}$). The proposed antenna operates in 2.5~2.56 GHz(VSWR<2). It showed that peak gain of the antenna is 1.96~2.48 dBi and overall beam width of the reconfigurable antenna covers about $125^{\circ}$.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.5
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• pp.223-230
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• 2014

In this paper, the single-fed microstrip parasitic array antenna for low-cost three-dimensional beam steering in 5.8GHz ISM(5.725GHz~5.825GHz) band is designed and implemented. The antenna is comprised of one feed active element and four passive elements with variable reactance loads. The beam steering range of implemented antenna is achieved three-dimensional beam steering of ${\pm}28^{\circ}$ at azimuth angle ${\Phi}=0^{\circ}$, ${\Phi}=45^{\circ}$, ${\Phi}=90^{\circ}$, and ${\Phi}=135^{\circ}$ by adjusting variable reactance loads. The maximum gain of the antenna in the beam steering range have within 7.23dBi~9.36dBi and the bandwidth of return loss lower than -10dB covers 5.8GHz ISM band regardless of the beam steering angles.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.8
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• pp.754-760
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• 2011

Reconfigurable beam steering using microstrippatch antenna with U-slot is proposed for wearable fabric applications. The proposed antenna is manufactured on a fabric substrate, and designed to steer the beam directions at the operation frequency of 6.0 GHz. The U-shaped slot and the indirect feeding-techniques are utilized in designing the proposed antenna. By the configuration of two artificial switches($S_0$, $S_1$, $S_2$) in between the indirect feed and the antenna patch, the antenna has three beam directions. The maximum beam directions are steerable in the yz-plane(${\theta}=0^{\circ}$, $30^{\circ}$, $331^{\circ}$), and the overall HPBW is $115^{\circ}$. The measured peak gains are 6.11~6.69 dBi.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.10
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• pp.1128-1136
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• 2012

In this paper, we propose an electrically tilting system based on a null-steering in order to solve the problem of the shadowing loss caused by the mechanically tilted antenna system in mobile services. Especially, we improve the downward shadowing loss by eliminating or moving the vertical beampattern nulls between $-30^{\circ}{\sim}0^{\circ}$ to be able to tilt the downward beampattern between $-10^{\circ}{\sim}0^{\circ}$. The antenna has 14.5 dBi gain and side lobe level (SLL) is lower than -18 dB within downward tilting range. The isolation of polarization is greater than 30 dB when running in electric tilt down to $-10^{\circ}$. To verify this paper, we made the base-station antenna for W-CDMA and beam tilting devices, and verified the performances.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.1 s.116
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• pp.7-14
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• 2007

In this paper, the scan characteristics of phased array antenna consisted of rectangular open-ended waveguide with a triangular grid are investigated. An infinite array structure is analyzed by numerically solving the integral equation for the electric field over the waveguide aperture using waveguide mode function and Floquet mode function. Next, SEP(Scan Element Pattern) and SI(Scan Impedance) characteristics are simulated by CST's MWS(Microwave Studio) and Ansoft's HFSS(High Frequency Structure Simulator) for the finite and infinite array structures. Also, validity of these approaches is verified by comparing the calculated and simulated results with the measured ones for an $8{\times}8$ subarray. Within 10.5 % fractional bandwidth in the X-band, the fabricated subarray showed the flat gain characteristic in the scan range of ${\pm}45^{\circ}C$ in the E-plane(azimuth) and ${\pm}20^{\circ}C$ in the H-plane(elevation), and also showed the return loss characteristic of less than -10 dB.