• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.3 no.2 s.5
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• pp.69-74
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• 2004

In this work, A PLDRO (Phase Locked Dielectric Resonator Oscillator) which can be used for the wireless communication systems fur MMC(Microwave Micro Cell) and ITS wireless communication system is designed. A different approach to the PLDRO structure is applied for phase locking by dual phase lock loop structure. The proposed dual loop PLDRO generates the output power of 0 dBm at 18.7 GHz and has the characteristics of a phase noise of -80 dBc/Hz at 1kHz, -83 dBc/Hz at 10 kHz offset frequency from carrier frequency

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.8
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• pp.426-431
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• 2005

A many-to-many k-disjoint path cover (k-DPC) of a graph G is a set of k disjoint paths joining k distinct source-sink pairs in which each vertex of G is covered by a path. In this paper, we investigate many-to-many 2-DPC in a double loop network G(mn;1,m), and show that every nonbipartite G(mn;1,m), $m{\geq}3$, has 2-DPC joining any two source-sink pairs of vertices and that every bipartite G(mn;1,m) has 2-DPC joining any two source-sink pairs of black-white vertices and joining any Pairs of black-black and white-white vertices. G(mn;l,m) is bipartite if and only if n is odd and n is even.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.4
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• pp.19-25
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• 2016

Using a actuator to which the motor and the gear is applied to the I-PD control method and a dual-loop system to carry out precise position control. I-PD control algorithm performs an operation to reduce the overshoot in the transient response. Accordingly, the actuator obtains a precise position tracking result. Also it utilizes two sensors and dual loops. It reduces the adverse effect on the precise position control that may occur by the end play of the gear train. In this paper, we uses the actuator model applying the BLDC motor and gear in order to determine the position tracking result by the dynamic characteristic change. It was verified by the simulation results.

• Journal of IKEEE
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• v.17 no.1
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• pp.16-21
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• 2013

Recently, frequency synthesizers are being designed in two ways narrow-band loop or dual-loop for wide-band to reduce the phase noise. However, dual-loop has the disadvantage of center frequency mismatch and requiring an extra loop. In this paper, we propose a new structure that supports a range of 800Mhz ~ 3Ghz with multiple control of the single-loop frequency synthesizer without another loop. The control voltage of the VCO(coarse, fine) will be fixed, and finally the VCO will have a low Kvco. The frequency synthesizer is simulated using UMC $0.11{\mu}m$ process, proposed frequency synthesizer can be used in a variety of applications in the future.

• Journal of the Korea Society of Computer and Information
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• v.4 no.1
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• pp.76-84
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• 1999

For FH/SS communication, We discussed the method of indirect frequency synthesizer in several methods. The problem of sing1e frequency synthesizer using with PLL is a varied coefficient value of damping factor in frequency hopping time, which is caused unstable frequency. So. for stable frequency synthesizer, a coefficient of damping factor must be optimized and synthesized to be removed excessive response time. In this paper, we studied FH using with double loop frequency synthesizer which takes stable frequency. We made up a simulator and had a good performance(real time speed).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.9
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• pp.775-782
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• 2016

In this paper, we propose a dual-band GPS antenna using a single-layer coupled-feed structure for improvement of isolation and design complexity. The proposed antenna consists of a central feed patch and outer dual loops, and the loops are electromagnetically fed by the feed patch to induce currents. This feeding network can improve the isolation between antenna elements arranged in small arrays because the magnetic field strength near the antenna is minimized by confining the fields around the dual loops. The isolation characteristics of the proposed antenna are compared with those of the conventional multi-layer patch antenna, and the average field strength and the isolation are improved by 3 dB and 2 dB, respectively, which verifies that the antenna is suitable for small CRPA arrays.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.11a
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• pp.67-68
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• 2012

전이중(full-duplex) 양방향 중계 네트워크는 전이중 방식을 사용하는 중계기에서 물리 계층 네트워크 부호화(physical layer network coding) 혹은 중첩 부호화(superposition coding)을 사용하여 기존 반이중(half duplex) 중계기를 사용하는 양방향 중계 네트워크에 비해 높은 주파수 효율을 제공한다. 본 논문에서는 전이중 양방향 중계 네트워크를 고려하여 전이중 방식에서 필연적으로 발생하는 루프간섭 신호의 영향을 살펴보았다. 여기에서 사용자 및 중계기는 루프간섭 신호를 제거하기 위해 루프간섭 신호를 추정한다. 하지만 루프간섭 신호를 추정할 때 추정 오류가 발생하여 수신 신호에서 루프간섭 신호를 완벽하게 제거하기는 어렵다. 모의실험에서는 이로 인해 발생할 수 있는 성능 변화를 불능 확률을 통해 분석하였다.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1987.04a
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• pp.144-147
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• 1987

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.2
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• pp.186-196
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• 2000

In this paper, modified square loop frequency selective surface for dualband communication antenna systems is proposed, and the scattering characteristics is discussed. The analysis for the problem of scattering by periodic structures with a dielectric slab is formulated using the spectral-domain immittance approach and Floquet's theorem. The method of moments which uses rooftop subdomain basis function is employed to solve the equations. Numerical results include the comparison between the transmission characteristic of general square loop and that of modified square loop. Also, the transmission characteristics of modified square loop for arbitrary incident angle and polarization is presented. To verify analysis results, modified square loop frequency selective surface was fabricated and the calculated results were compared with the measured results. The measured results showed good agreement with the calculated results.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.5
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• pp.49-58
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• 2018

This paper introduces a research on the control method design for the subsonic intake flow of a dual-combustion ramjet engine. To design the control method, the intake flow dynamic response characteristics, based on a designated flow condition and intake geometry, are investigated, and a control method concept considering the intake flow characteristics is established. Using a dynamic simulation model of a dual-combustion ramjet, control input/output linearized models are obtained such that a control loop design based on linearized models can be accomplished. Finally, from various control loop simulations, the performance of the control method, including its control loop stability, is evaluated.