• ETRI Journal
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• 제25권2호
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• pp.65-72
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• 2003

To achieve cost and size reductions, we developed a low cost manufacturing technology for RF substrates and a high performance passive process technology for RF integrated passive devices (IPDs). The fabricated substrate is a conventional 6" Si wafer with a 25${\mu}m$ thick $SiO_2$ surface. This substrate showed a very good insertion loss of 0.03 dB/mm at 4 GHz, including the conductive metal loss, with a 50 ${\Omega}$ coplanar transmission line (W=50${\mu}m$, G=20${\mu}m$). Using benzo cyclo butene (BCB) interlayers and a 10 ${\mu}m$ Cu plating process, we made high Q rectangular and circular spiral inductors on Si that had record maximum quality factors of more than 100. The fabricated inductor library showed a maximum quality factor range of 30-120, depending on geometrical parameters and inductance values of 0.35-35 nH. We also fabricated small RF IPDs on a thick oxide Si substrate for use in handheld phone applications, such as antenna switch modules or front end modules, and high-speed wireless LAN applications. The chip sizes of the wafer-level-packaged RF IPDs and wire-bondable RF IPDs were 1.0-1.5$mm^2$ and 0.8-1.0$mm^2$, respectively. They showed very good insertion loss and RF performances. These substrate and passive process technologies will be widely utilized in hand-held RF modules and systems requiring low cost solutions and strict volumetric efficiencies.

• 제어로봇시스템학회논문지
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• 제13권10호
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• pp.949-955
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• 2007

This paper proposes an efficient localization algorithm in the RFID sensor space for the precise localization of a mobile robot. The RFID sensor space consists of embedded sensors and a mobile robot. The embedded sensors, that is tags are holding the absolute position data and provide them to the robot which carries a reader and requests the absolute position fur localization. The reader, it is called as antenna usually, gets several tag data at the same time within its readable range. It takes time to read all the tags and to process the data to estimate the position, which is a major factor to deteriorate the localization accuracy. In this paper, an efficient algorithm to estimate the position and orientation of the mobile robot as quickly as possible has been proposed. Along with the algorithm, a new allocation of the tags in the RFID sensor space is also proposed to improve the localization accuracy. The proposed algorithms are demonstrated and verified through the real experiments.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2003년도 ISIS 2003
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• pp.244-247
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• 2003

All over the value chain, a logistics information system must satisfy several requirements about gathering and sharing related information. For example, distributors or forwarders need up-to-date information for scheduling and managing their logistics resources. Meanwhile, consignors or consignees want to know the dynamic information about current states or location of their goods. Such information is dependent upon the quality of data sets collected throughout the logistics processes. Thus, gathering accurate data promptly is the essential factor for the success of a logistics information system. However, there are limits in reducing both time-gap and man-power for datn sourcing, since this process is done manually or by using bar codes and scanning devices. Smart-tag can be the alternative to such n time-consuming and inefficient operation, especially for handling piles of goods. The tag includes a micro-chip containing data which is remotely readable by readers with antenna. Logistics system with Smart tag can provide all the information anywhere and anytime, and it will increase the efficiency of logistics and satisfaction of users. In this paper, we propose a conceptual architecture for smart-tag based logistics system and describe its functions.

• 한국위성정보통신학회논문지
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• 제3권2호
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• pp.48-53
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• 2008

In the future, satellite communication systems, such as ISDB in Japan and DVB in Europe, are required to support higher transmission date rate for providing multimedia services including HDTV, high rate data communication etc. Considering the effectiveness of OFDM technique in efficient usage of frequency bandwidth and its robustness to the multi-path fading, several OFDM based standards have been proposed for satellite communication. However, the problem of high Peak to Average Power Ratio is one of the main obstacles for the implementation of OFDM based system. Many PAPR reduction schemes have been proposed for OFDM systems. Among these, the partial transmit sequences (PTS) is attractive as they obtain better PAPR property by modifying OFDM signals without distortion. In this paper, considering the complexity issue, we present a simplified minimum maximum (minimax) criterion and Sub-Optimal PTS algorithm to optimize the phase factor. This algorithm can be dynamically made tradeoff`f between performance and complexity on demand. In addition, we integrate guided scrambling (GS) with this method. Simulation in multiple antenna based OFDM system proves that the proposed Hybrid schemes can get much more PAPR reduction and do not require transmission of side information (SI). Thus it is helpful when implementing OFDM technique in satellite communication system.

• 한국전자파학회지:전자파기술
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• 제6권3호
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• pp.24-35
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• 1995

본 눈문에서는 기존 무선통신 시스댐의 스펙트럼 이용정도를 계량화할 수 있는 스펙트럼 이용척도 모텔을 연 구한다- 이모텔은 간섭 예측프로세스의 EMC 분석기법을 적용하여 송신기와 수신기사이의 간섭레벨읍 계산한 다. 많은 기존연구가 무선시스템의 주위에 간섭 등고선을 구성함으로서 스펙트럼 자원을 묘사한 반면에 조사한 방볍은 무선시스댐이 이용하고 있는 스펙트럼자원을 계량화하여 지형적인 영역 위에 묘사할 수 있도복 개발되 었다. 스펙트럼 이용척도모텔인 스펙트럼 이용대역폭과스펙트럼 이용요소의 계산을 검증하고그모델의 유용 성을 분석하기 위하여 컴퓨터 시율레이션을 수행하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기물성,응용부문
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• pp.281-284
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• 2004

In Recent, it became necessary to envelope the technology about electrodeless fluorescent lamp according to demand of the electrodeless fluorescent lamp system that used higher efficiency and advantage of long-lifetime. Especially, in the electrodeless fluorescent lamp which used H-mode, efficiency of lamp is decided from matching parameter of antena and inverter So it is of the utmost importance to design antena and inverter. Therefore, this paper used a transformer principle for efficiency rising of electrodeless fluorescent lamp and interpreted an equivalent circuit, used an impedance analyzer in order to confirm a performance enhancement of lamp along design of antenna, and confirmed parameter characteristic of R, L, C, Z, Phase, Q-factor along a change of magnetic flux density. Also, this paper confirmed a luminance characteristic of electrodeless lamp along parameter change with measuring optical characteristic along a change of magnetic flux density.

• 전기학회논문지
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• 제61권7호
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• pp.1024-1031
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• 2012

In this paper, FMCW type radar level transmitter using correlation analysis method is implemented for precise distance measurement of cargo tank. FMCW type radar level transmitter is the device for distance measurement which calculates the distance by analyzing the beat frequency, that is, the frequency difference between Tx and RX signal from radar antenna using Fast Fourier Transform(FFT), but compensated algorithm like Zoom FFT is needed for the improvement of the frequency precision because the frequency precision of FFT is limited depending on sampling frequency and the number of sampling data. In case of Zoom FFT, the number of sampling data and noisy signal are the main factor influencing the measurement accuracy of Zoom FFT like FFT. Therefore, in order to overcome the limited environment and achieve the precise measurement, correlation coefficient is used for the distance measurement and the errors of measurement are verified to be in the range of ${\pm}1mm$.

• 한국정보통신학회논문지
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• 제19권2호
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• pp.293-300
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• 2015

우수한 성능의 OFDM 전송을 위하여, 각 사용자에게 유리한 채널을 할당하는 다중 사용자 다이버시티(MUD) 방식이 최근 사용되고 있다. 또한 시스템의 성능을 향상시키기 위하여 STBC 안테나 다이버시티 방식이 현재 사용되고 있다. 파일럿 심볼을 이용하여 전송 채널을 추정하는 현 시스템에서는 채널 추정 오차로 인하여 시스템의 성능이 열화 된다. 그러므로 본 논문에서 채널 추정 오차의 영향을 고려하여 MUD STBC OFDM 전송 시스템의 비트 오류율 성능을 분석한다. 분석 결과, MUD를 사용한 시스템에서는 같은 비트 오류율에 대하여 사용자 수가 32인 경우에 5 dB 정도의 다이버시티 전력 이득을 얻는다.

• 한국정보통신학회논문지
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• 제13권2호
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• pp.221-226
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• 2009

비선형 곡선 형상의 레이돔은 안테나 보호를 위해 적당한 기계적 강도와 RF(Radio Frequency)적으로 전기적 성능 저하가 최소화 될 수 있도록 설계 되어져야 한다. 특히 전기 적 성능은 원소재가 가지는 유전율에 따라 좌우되는 중요 요소로서 제조 과정에서 관리하여야 하는 중요한 인자중 하나이다. 본 연구에서는 레이돔 제조 공정 중에서 유전율에 영향을 미치는 주요 인자를 실험을 통하여 밝혀내고, Simulation을 통하여 유전율이 레이돔의 전기적 성능에 미치는 영향을 파악한다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.531-534
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• 2004

In Recent, it became necessary to develope the technology about electrodeless fluorescent lamp according to demand of the electodeless fluorescent lamp system that used higher efficiency and advantage of long-lifetime. Especially, in the electordeless fluorescent lamp which used H-mode, efficiency of lamp is decided from matching parameter of antena and inverter. So it is of the utmost importance to design antena and inverter Therefore, this paper used a transformer principle for efficiency rising of electrodeless fluorescent lamp and interpreted an equivalent circuit, used an impedance analyzer in order to confirm a performance enhancement of lamp along design of antenna, and confirmed parameter characteristic of R, L, C, Z, Q-factor along a change of magnetic flux density. Also, this paper confirmed a luminance characteristic of electordeless lamp along parameter change with measuring optical characteristic along a change of magnetic flux density