• Title/Summary/Keyword: 가변 전송 선로

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Design of a Miniaturized 5.3 GHz 360° Analog Phase Shifter (소형화된 5.3 GHz 대역 360° 아날로그 위상천이기 설계)

  • Jeong, Hae-Chang;Son, Bon-Ik;Lee, Dong-Hyun;Ahmed, Abdul-Rahman;Yeom, Kyung-Whan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.24 no.6
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    • pp.602-612
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    • 2013
  • In this paper, a design and fabrication of miniaturized 5.3 GHz reflection type $360^{\circ}$ analog phase shifter with branch line coupler and $360^{\circ}$ variable reactance load. In order to miniaturize phase shifter, novel branch line coupler is proposed. The novel branch line coupler is miniaturized using transformation of transmission line to T and ${\pi}$ type equivalent circuit. The miniaturized branch line coupler has small size of above 50 % compared with conventional branch line coupler. For wide phase shift range, $360^{\circ}$ variable reactance load structure is adopted. Especially, the structure was improved for linear phase shift by adding transmission line which acts as an impedance transformer. The improved structure was miniaturized using the equivalent lumped-element of transmission line. The fabricated phase shifter with $15{\times}15mm^2$ shows wide phase shift of above $480^{\circ}$, the insertion loss of -4~-6 dB and the reflection loss of below -20 dB at 5.3 GHz under 0~10 V control voltage range.

A Study on the ASK Communication Modem over Electrical Power Lines (전력선을 이용한 ASK통신 모뎀에 관한 연구)

  • 사공석진;송문규
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.17 no.9
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    • pp.951-962
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    • 1992
  • The layout of electrical power distribution networks never involved communications aspects. As a result their transmission properties severly complicate the use as data links. Futhermore bandwidth as well as transmission power is restricted. Nevertheless, power distribution net works represent a most attractive medium for digital communication purposes due to an ever increasing demand, e.g., for environment management of buildings, office automation, and remote meter reading or security monitoring. In this paper, a power line modem which is capable of transmitting and receiving data at 1200 bps using OOK-BASK through 220V AC power lines is implemented. The receiver includes noncoherent detector and performs soft decision. The OLM circuits can be simplified by use of microprocessor. The PLM also satisfies CENELEC, European standards, and can be applied to home automation system.

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TCP-RLDM : Receiver-oriented Congestion Control by Differentiation for Congestion and Wireless Losses (TCP-RLDM: Congestion losses과 Wireless losses 구별을 통한 수신측 기반 혼잡제어 방안)

  • 노경택;이기영
    • Journal of the Korea Society of Computer and Information
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    • v.7 no.4
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    • pp.127-132
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    • 2002
  • This paper aims to adjust the window size according to the network condition that the sender determines by making the receiver participating in the congestion levels. TCP-RLDM has the measurement-based transmission strategy based on the data-receiving rate complementing TCP with the property of Additive Increase / Multiplicative Decrease. The protocol can make an performance improvement by responding differently according to the property of errors-whether congestion losses or transient transmission errors - to confront dynamically in heterogeneous environments with wired or wireless networks and delay-sensitive or -tolerant applications. By collecting data-receiving rate and the cause of errors from the receiver and by enabling sender to use the congestion avoidance strategy before occuring congestion possibly, the protocol works well at variable network environments.

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Study for generation of standard EM field using 8 ports-variable wave impedance generator (8단자 가변 임피던스 전자파 발생 장치를 이용한 표준 복사 전자기장 조성 연구)

  • 윤재훈
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.21 no.3
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    • pp.771-783
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    • 1996
  • A desing technique of 8 ports variable wave impedance generator (8P-VWIG) is described. The design technique employs not only a numerical algorithm to find the structure with arbitrary characteristic impedance, but also a numerical solution to analyze the uniform elementrognentic fields established inside the generator. The 8P-VWIG so obtained is shown to have good performance with the VSWR of less than 1.4 at any frequency of interest below which higher order mode begin to propagate. The measured first resonant frequency is 152.1 MHz. The 8P-VWIG is designed based on the concept of an expanded multi-transmission line(8 channel). It is especially useful for the electronmagnetic interference(EMI) and electronmagnetic susceptibility(EMS) testing since it maximizes usable test crosssectional area, and its is easy change the polarization, vertical or horizontal, of field.

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RFID Mutual Authentication Protocol Using Nonfixed Symmetric Key Based on Shift Computation and Random Number (시프트 연산과 난수를 이용한 가변적 대칭키 기반의 RFID 상호인증 프로토콜)

  • Lee, Jae-Kang;Oh, Se-Jin;Chung, Kyung-Ho;Lee, Chang-Hee;Ahn, Kwang-Seon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.5B
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    • pp.377-384
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    • 2012
  • RFID system is a technique to obtain information of tag using radio frequency. Specificity of RFID systems using radio frequency has many problems that is eavesdropping, location tracking, spoofing attack, replay attack, denial of service attack. So, RFID protocol should be used cryptographic methods and mutual authentication for security and privacy. In this paper, we explain the problem of past protocol and propose the nonfixed symmetric key-based RFID mutual authentication protocol using shift computation and random number. Proposed protocol is secure from various attacks. Because it use shift operation and non-fixed symmetric key.

A Study on Characteristics of Microwave Transmission Line of Rectangular Split Ring Resonator (사각 분리형 링 공진기의 마이크로파 전송선로 특성 연구)

  • Kim, Girae
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.3 no.2
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    • pp.25-30
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    • 2010
  • In this paper, a novel notch resonator is proposed based on Rectanglar Split Ring Resonator (R-RSS) element. We represented the electrical characteristics for R-SRR elements coupled with microstrip line, and measured result is compared with electromagnetic simulation (HFSS) result. We also solved equivalent circuit for R-SRR element, and also discussed influences of change structural parameters of R-SRR. the size of R-SRR is the most important parameters for frequency tuning. Also we can make tunable resonator form the basic structure. This novel resonator can apply to design of tunable bandpass filter and voltage control oscillator.

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Hybrid Buffer Structured Optical Packet Switch with the Limited Numbers of Tunable Wavelength Converters and Internal Wavelengths (제한된 수의 튜닝 가능한 파장변환기와 내부파장을 갖는 하이브리드 버퍼 구조의 광 패킷 스위치)

  • Lim, Huhn-Kuk
    • Journal of Internet Computing and Services
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    • v.10 no.2
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    • pp.171-177
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    • 2009
  • Optical packet switching(OPS) is a strong candidate for the next-generation internet, since it has a fine switching granularity at the packet level for providing flexible bandwidth, and provides seamless integration between WDM layer and IP layer. Optical packet switching have been studied in two categories: OPS in synchronous and OPS in asynchronous networks. In this article we are focused on contention resolution of OPS in asynchronous networks. The hybrid buffer have been addressed, to reduce packet loss further as one of the alternative buffer structures for contention resolution of asynchronous and variable length packets, which consists of the FDL buffer and the electronic buffer. The OPS design issue for the limited number of TWCs and internal wavelengths is important in the aspect of switch cost and resource efficiency. Therefore, an hybrid buffer structured optical packet switch and its scheduling algorithm is presented for considering the limited number of TWCs and internal wavelengths, for contention resolution of asynchronous and variable length packets. The proposed algorithm could lead to the packet loss improvement compared to the legacy LAUC-VF algorithm with only the FDL buffer.

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Method of Harmonic Magnitude Quantization for Harmonic Coder Using the Straight Line and DCT (Discrete Cosine Transform) (하모닉 코더를 위한 직선과 이산코사인변환 (DCT)을 이용한 하모닉 크기값 (Magnitude) 양자화 기법)

  • Choi, Ji-Wook;Jeong, Gyu-Hyeok;Lee, In-Sung
    • The Journal of the Acoustical Society of Korea
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    • v.27 no.4
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    • pp.200-206
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    • 2008
  • This paper presents a method of quantization to extract quantization parameters using the straight-line and DCT (Discrete Cosine Transform) for two splited frequency bands. As the number of harmonic is variable frame to frame, harmonics in low frequency band is oversampled to fix the dimension and straight-lines present a spectral envelope, then the discontinuous points of straight-lines in low frequency is sent to quantizer. Thus, extraction of quantization parameters using the straight-line provides a fixed dimension. Harmonics in high frequency use variable DCT to obtain quantization parameters and this paper proposes a method of quantization combining the straight-line with DCT. The measurement (If proposed method of quantization uses spectral distortion (SD) for spectral magnitudes. As a result, The proposed method of quantization improved 0.3dB in term of SD better than HVXC.

A Frequency Adjustable Double Lorentz CRLH Transmission Line using DGS (DGS를 이용한 주파수 가변 DL-CRLH 전송선로)

  • Lim, Jong-Sik;Lee, Jae-Hoon;Lee, Jun;Jeong, Yong-Chae;Han, Sang-Min;Ahn, Dal
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.8
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    • pp.1429-1435
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    • 2010
  • In this paper, a double lorentz composite right left handed(DL-CRLH) transmission line is designed using defected ground structure (DGS) and varactor diodes. Previously, the diode has been adopted only selectively for one of parallel or series resonators, and the balanced frequency as well as triple band frequencies were fixed. However in the proposed DL-CRLH transmission line, the balanced frequency, where the resonant frequencies of the series-connected parallel resonator and shunt-connected series resonator are the same, is adjustable. In addition, the triple band frequencies are controlled, too. The measured balanced frequency varies between 3.42~4.8GHz according to the controlled bias voltage. Under the same bias condition for the balanced frequency, the adjusted frequencies are 2.22~2.77GHz, 3.7~5.2GHz, 7.32~8.23GHz, 3.42~4.8GHz, and 4.44~5.92GHz for the conditions that ${\beta}d=+0.5{\pi}$, $-0.5{\pi}$, 2nd $+0.5{\pi}$, ${\omega}_{\infty}$, and ${\omega}_o$, respectively.

Magnetically tunable narrow band stop and/or pass directional coupling YIG filter (YIG를 사용한 자계동조 방향성결합 협대혁 통과 및 차단 여파기)

  • Park, Gyu-Tae;Lee, Jong-Ak;Hwang, Geum-Chan
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.8 no.4
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    • pp.25-30
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    • 1971
  • Fabrication and measurements of the magnetically tunable YIG band pass or stop filter at X-band are discussed. Using two YIG spheres located at the region of r-f circularly polarized magnetic field between the strip lines, the pass or stop characteristics of the filter are obtained. In the case of band stop, the output level is typically 25db lower than the input power. Contrarily for the pass band, the pass band level is 22db higher than the stop frequency region. The experimental results are in good agreement with the theoretical values of FMR. Further it is shown that the structure can be used for a directional coupler.

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