• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.4 no.1
• /
• pp.53-60
• /
• 2011

In-Home Display (IHD) is one of the most popular ways to induce voluntary customer participation in energy savings. Various communication technologies are used for recent IHD implementations, but most IHD systems are designed for each house because of their limitations such as communication coverage area and operation complexity. In this study, 400MHz RF communication is used for economical large-scale deployment of IHDs especially for apartment complexes that represent typical residentioal environment in Korea. Since it is essential to use internal batteries to increase the usability of IHD, the frequent changes of them should be avoided. By dividing communication data into 3 types such as common data, long term data, and short term data depending on their update periods, energy efficient communication protocol is designed and proposed. In result, the quantity of data and the battery consumption of IHD are reduced to 23.4% and 31.5% each without harming service quality.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.4A
• /
• pp.350-357
• /
• 2005

DSRC provides high speed radio link between Road Side Equipment and On-Board Equipment within the narrow communication area. In this paper, a 5.8 GHz up-conversion mixer for DSRC communication system was designed and fabricated using 0.8 m SiGe HBT process technology and IF/LO/RF matching circuits, IF/LO input balun circuits, and RP output balun circuit were all integrated on chip. The chip size of fabricated mixer was $2.7mm\times1.6mm$ and the measured performance was 3.5 dB conversion gain, -12.5 dBm output IP3, 42 dB LO to If isolation, 38 dB LO to RF isolation, current consumption of 29 mA for 3.0 V supply voltage.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38A no.12
• /
• pp.1061-1068
• /
• 2013

In this paper, we propose a $M{\times}M$ beam-space multiple input multiple output (BS-MIMO) system using electronically steerable parasitic array radiator (ESPAR) antenna. Conventional MIMO method required multiple RF chains because it map the transmission signals onto multiple antennas. So, conventional MIMO system has high cost for design and high energy consumption at RF circuit. Also, It is difficult to use MIMO system in battery based mobile terminals with limited physical area. In order to solve these problems, BS-MIMO technique which map the data signal onto bases in beam space domain was proposed using ESPAR antenna with single RF chain. This paper, we design and analyze the performance of extended $M{\times}M$ BS-MIMO technique. Simulation results show that the proposed BS-MIMO system has similar BER performance compare to conventional MIMO scheme. Therefore, BS-MIMO system with single RF chain will has a low RF power consumption and low cost for RF hardware design as compared with conventional MIMO technique with multiple RF chains.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.39A no.10
• /
• pp.616-618
• /
• 2014

In this paper, we designed the accelerated life testing(ALT) and presented the lifetime prediction method of the RF SAW duplexer. We determined RF input power as an accelerated stress when designing an accelerating life testing and defined the lifetime of the duplexer as the period during which the insertion loss increased by 0.5[dB]. Lifetime prediction results of duplexer was estimated for 82,900hours at an ambient temperature of $85^{\circ}C$ and RF input power of 30[dBm].

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.12 no.3
• /
• pp.282-289
• /
• 2019

Reflective and solar LED road studs are being used as a way of securing visibility for road environments. Road markers have various advantages and disadvantages in terms of versatility, efficiency, simplicity and visibility as individual products of reflective type and solar LED. However, in addition to the above, it is possible to prevent secondary accident after accident, It has a common drawback that it is difficult to have. In this paper, we propose a road stud system incorporating a wireless control function using RF - based communication with existing solar LED road studs and a system for controlling them. The proposed system is called the smart road stud system and it can control the equipment through the central control unit and the relay unit connected to the central control room by incorporating the RF communication function in the existing solar LED road stud. In addition, since it is possible to control the lighting method, color, etc. according to the road condition, it is possible to provide the driver with the state of the road to perform the function for preventing the second accident after the accident. It also adds features that minimize the ongoing power consumption of LED and RF communications. In order to verify the validity of the proposed system, prototypes were produced and it was confirmed that it is possible to act as a university for prevention of accident after accident by linking with other traffic system besides accident prevention function by securing existing visibility.

• Journal of Astronomy and Space Sciences
• /
• v.15 no.2
• /
• pp.509-523
• /
• 1998

Before an actual military communications satellite is designed and constructed, a feasibility study should take place. The basic functions of such system can be observed and demonstrated in an X-Band payload simulator. For this purpose a Payload Concept Model (PCM) for X-Band payload subsystem has been developed to simulate the workings of an actual military communications payload. This paper explains and illustrates the mechanical design, manufacture, and integration of the PCM. Basic RF tests also have been performed in order to verify the design requirement of the system. The results demonstrate successful development of the PCM and operation without RF losses.

• 한국정보통신설비학회:학술대회논문집
• /
• 2003.08a
• /
• pp.289-292
• /
• 2003

최근 무선통신 분야의 급속한 성장은 양적인 성장에 이어 보다, 고품질의 서비스를 요구하게 되었다. 무선통신 환경에서는 전파강도의 부족으로 전파가 도달할 수 없는 음영지역이 발생하게 되는데 이러한 음영지역까지 통신이 가능하도록 하기위해 기지국으로부터 받은 신호를 재증폭하는 중계기를 사용한다. 이때 중계기의 수신단과 송신단 간의 격리도가 충분히 확보되지 않으면 발진이 일어나 서비스 품질을 떨어뜨리게 된다. 본 논문에서는 중계기에서 신호를 효율적으로 전송하기 위해 수신안테나와 송신안테나 사이의 격리도를 개선할 수 있는 방법으로 반사판의 사용과 홈(groove) 기법, 안테나의 편극을 이용하여 1900MHz PCS 대역에서 50dB 이상의 격리도를 확보할 수 있음을 보인다.

• Electronics and Telecommunications Trends
• /
• v.25 no.2
• /
• pp.42-56
• /
• 2010

메타전자파구조(메타물질: MTM(Metamaterials)) 기술은 기존의 기술로는 불가능했던 주파수 독립적인 파장 위상 및 굴절률 제어가 가능한 신개념의 차세대 혁신 기술로서 정보통신기기, 전자제품 등의 초소형화, 고성능화 등의 실현이 가능하며 고성능/고효율의 전파통신 부품, 광통신 부품, 의료진단 영상장치, 보안 감시 시스템 등에 응용되어 유비쿼터스 사회의 산업 전반에 지대한 파급 효과를 미칠 것으로 보고 선진 각국에서는 차세대 핵심 원천 기술로서 개발을 경쟁적으로 추진하고 있다. 따라서 본 고에서는 이러한 기술적인 발전 추세에 맞추어 마이크로파 대역에서 MTM 설계 기술과 안테나 및 RF 부품의 성능 개선을 위한 MTM 응용 기술에 대하여 살펴보고자 한다.

• 한국정보통신설비학회:학술대회논문집
• /
• 2008.08a
• /
• pp.296-299
• /
• 2008

최근 통신시스템과 핸드폰, PDA등의 통신기기들의 발전에 따라 사용자들은 높은 데이터 전송률과 고속의 통신서비스를 요구하고 있다. 이러한 상황에서 유 무선 통합 시스템인 Radio-over-Fiber(RoF) 시스템은 그 대안으로 대두되고 있다. 본 논문에서는 광전자소자를 선 왜곡 방식에 적용하여 광 송신기의 선형성을 향상시키는 방법을 제안하였다. 선 왜곡 방식은 두 개의 루프로 구성되어 있으며, 광 부품인 레이저 다이오드와 포토 다이오드 그리고 RF 부품인 위상변위기, 감쇄기, RF 결합/분배기, RF 증폭기를 사용하였다. 메인 루프에서 주 레이저 다이오드의 비선형성에 의해 발생된 왜곡신호성분은 보조 루프에서 부 레이저 다이오드를 이용하여 추출된 선 왜곡신호에 의해서 제거된다. 제안된 선형화 기법을 적용하여 2.4 GHz에서 선형화 기법을 적용하기 전보다 3차 상호변조 왜곡성분이 약 30dB 향상된 결과를 얻었다.

• Information and Communications Magazine
• /
• v.10 no.11
• /
• pp.28-39
• /
• 1993