• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.11
• /
• pp.2541-2546
• /
• 2013

In this paper, we proposed on the azimuth correction method for a line-of-sight data-link tracking antenna system. Tracking antenna system is essential to maintain line-of-sight between moving object and data-link equipment. In order to calculate the azimuth and elevation between the moving object and antenna system, we used GPS data. also to match the each coordinate systems, we used geomagnetic sensor or beacon. However, the geomagnetic disturbance-prone terrain in places difficult to correct calibration. The first step, finds the location of the strongest RF signal, we should remember the difference between the reference point and the detected position of the antenna. The second step, we could communicate each other. And the azimuth angle is calculated by GPS values. Despite the geomagnetic interference, we can correct the azimuth angle quickly and easily.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2002.05a
• /
• pp.197-200
• /
• 2002

The current Inn technique is many problems that is permission of radio station using RF Wireless Modem, that is influence of geographic obstacle using radio wave, that is frequency interference, that is finiteness of frequency resources. In this paper, we are solved many elements, IM replaces RF Wireless Modem, we suggest transmission technique of correction message using mobile phone, we researched Interface Module development which is linkage of DGPS receiver and mobile phone. IM can transmit correction message passing RS-232 port and modem communication control. IM of base station is initialized RS-232 port and modem to move station for correction message transmission, IM waited response mode. IM of move station is initialized RS-232 port and modem, IM requests hand shaking to base station, completed connection establishment. Users are worked Differential surveying using receiving correction message between mobile phones.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.13 no.10
• /
• pp.2121-2128
• /
• 2009

The application range of IEEE 802.11 wireless LAN has rapidly expanding from campus, enterprise to the public network of Hot Spot area due to the advantages of easiness of construction, mobility of wireless client station, convenience of usage and so on. However the security of WLAN(Wireless LAN) is vulnerable inherently because of using RF as a medium, and so the dangers of infringement of personal information and inside data of enterprises have increased and wardriving attack searching for security vulnerability in wireless LAN has become more serious especially. In this paper, we find out the overview of various procedures and preparatory stages for wardriving attack against wireless LAN, and propose complementary methods to prevent information infringement accidents from wardriving attack in wireless LAN. For this purpose, we make an equipment which is suitable for wardriving in wireless LAN and show security vulnerability of AP(Access Point) operation in WLAN around Yangjae-Dong in Seoul as a result of using the equipment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2010.06a
• /
• pp.135-135
• /
• 2010

본 연구에서는 ZnO를 기반으로 하여 $In_2O_3$, $Ga_2O_3$를 혼합한 IGZO 박막의 물성들을 분석하였다. 광학적 특성 결과 가시광 영역에서 모두 80%이상의 투과율을 나타내었으며, 전기적 특성을 조사한 결과 $In_2O_3:Ga_2O_3$:ZnO (1:9:90 wt.%)의 IGZO박막에서 $1.90{\times}10^{-3}\;\Omega/cm$의 비저항을 확인 할 수 있었다. 또한 상온에서 $400^{\circ}C$로 기판온도에 변화를 주어 실험하였으며, 결정성을 분석하기 위하여 XRD (PANALYTICAL CO.)를 사용하였고, SEM (JEOL CO.) 을 이용하여 IGZO박막의 미세 구조를 확인하였다. UV-ViS spectrophotometer (SHIMADZU CO.) 을 사용하여 광학적 특성을 측정하였으며, Hall effect측정 장비를 이용하여 캐리어 농도 및 Hall이동도 변화에 따른 비저항을 비교 분석하였다.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.37 no.1
• /
• pp.8-18
• /
• 2000

We presented a BGA(Ball Grid Array) package for RF circuit modules and extracted its electrical parameters. As the frequency of RF system devices increases, the effect of its electrical parasitics in the wireless communication system requires new structure of RF circuit modules because of its needs to be considered of electrical performance for minimization and module mobility. RF circuit modules with BGA packages can provide some advantages such as minimization, shorter circuit routing, and noise improvement by reducing electrical noise affected to analog and digital mixed circuits, etc. We constructed a BGA package of ITS(Intelligent Transportation System) RF module and measured electrical parameters with a TDR(Time Domain Reflectometry) equipment and compared its electrical parasitic parameters with PCB RF circuits. With a BGA substrate of 3${\times}$3 input and output terminals, we have found that self capacitance of BGA solder ball is 68.6fF, and self inductance 146pH, whose values were reduced to 34% and 47% of the value of QFP package structure. S11 parameter measurement with a HP4396B Network Analyzer showed the resonance frequency of 1.55GHz and the loss of 0.26dB. Routing length of the substrate was reduced to 39.8mm. Thus, we may improve electrical performance when we use BGA package structures in the design of RF circuit modules.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.16 no.4
• /
• pp.187-192
• /
• 2023

This paper deposited CdTe thin films on ITO glass substrates using sputtering equipment while changing RF power. As a result of measuring the thickness of the thin film, 1481Å at 100W, 2985Å at 150W, and 4684Å at 200W. And the mobility was measured as 8.43 cm2/Vs for 100W, 7.91 cm2/Vs for 150W, and 6.57 cm2/Vs for 200W. It can be seen that the thickness and mobility of the thin film are inversely proportional. As a result of confirming the transmittance, the transmittance was 84% at 905nm for 100W, the transmittance was 71% at 825nm for 150W, and 77% at 874nm for 200W. At 100 W, the thickness of the thin film was thin, so the transmittance was measured to be high. In other words, the correlation between transmittance and thickness can be seen. As a result of measuring the FHWM and particle size by changing the RF Power, 100W was calculated as 0.18, 150W was calculated as 0.19, and 200W was calculated as 0.73. The size of the particles was formed at 8.47Å at 100W, 7.98Å at 150W, and 8.7Å, which is the largest at 200W. In conclusion, it was found that the FHWM and particle size were inversely proportional.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.95-95
• /
• 2011

비정질 산화물 반도체(Amorphous oxide semiconductors: AOSs)는 대면적화에도 불구하고 높은 이동도를 가지고, 상온에서도 제작할 수 있고, 투명 플렉시블 디스플레이 소자에 사용할 수 있기 때문에 최근 들어 각광받고 있는 연구 분야이다. 본 연구에서는 스퍼터링을 이용하여 활성층을 Amorphous indium gallium zinc oxide(a-IGZO)로 증착할 시에 스퍼터의 파워와 챔버내의 Ar/O2 비율을 다르게 했을 때 소자에 미치는 영향을 MIS구조를 이용하여 분석했다. 또한 같은 조건의 a-IGZO 활성층을 사용한 박막트랜지스터(TFT) 소자의 절연막의 종류를 바꿔가며 제작했을때의 소자의 특성 변화에 대해서도 분석하였다. 먼저 60 nm 두께의 a-IGZO층을 Heavily doped된 N형 실리콘 기판위에 스퍼터링 파워와 가스 분압비를 달리하여 증착하였다. 그 후 30 nm두께의 SiO2, Al2O3, SiNx 절연막을 증착하고, 마지막으로 열 증발 증착장비(Thermal Evaporator)를 이용하여 Al 전극을 150nm 증착하였다. 소자의 전기적 특성 분석은 HP4145와 Boonton 720을 사용하여 I-V와 C-V를 측정하였다. 위의 실험으로부터 스퍼터에서의 증착 rf파워가 증가할수록 a-IGZO 박막 트랜지스터에서의 캐리어 이동도가 감소하는 것을 볼 수 있었고, 챔버내의 가스분압비와 소자의 절연막의 종류가 변하면 a-IGZO 박막 트랜지스터의 전기적 특성이 변하는 것을 볼 수 있었다. 이러한 캐리어 이동도의 감소와 전기적 특성의 변화의 이유는 a-IGZO 활성층의 bulk trap과 절연막, 활성층 사이의 interface trap에 의한 것으로 보여진다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37C no.12
• /
• pp.1281-1288
• /
• 2012

This paper presents the design and implementation of a multi-mode mobile broadcasting Emergency Warning System (EWS) transmission and reception system which enables the propagation of disaster information using the encoding and transmission, reception and decoding methods specified in diverse mobile broadcasting standards. The implemented system supports global mobile broadcasting standards such as Terrestrial Digital Multimedia Broadcasting (T-DMB), Digital Video Broadcasting-Handheld (DVB-H), Integrated Services Digital Broadcasting-Terrestrial (ISDB-T), and the Digital Radio Mondiale (DRM) digital radio standard. The system consists of two key part: an encoding/transmission part and a reception/decoding part. The multi-mode mobile broadcasting EWS encoding and transmission system generates EWS data according to each broadcasting specification. The generated EWS data is then transmitted through a channel interface which meets the commercial broadcasting equipment specification. The receiver system receives and decodes the EWS data on a single hardware platform and can display the results on screen. Verification and conformity testing has been carried out on the implemented system by transmitting emergency data for each mode in real-time and displaying the received information in text on the receiver display.

• Journal of Navigation and Port Research
• /
• v.26 no.4
• /
• pp.419-426
• /
• 2002

The conventional RTK-GPS technique has many problems which are permission using RF wireless modem, influence of geographic obstacle using radio wave, frequency interference, finiteness of frequency resources. To solve these problems, in this paper, we designed the DGPS correction message transmission system as a method to substitute the RF wireless modem of RTK-DGPS receiver. Then the interface module was designed and implemented for linkage of GPS receiver and mobile phone. As a result worked differential surveying using receiving correction message using RS-232C and communication control, users of mobile station were worked differential surveying correction between mobile phones. Interface module system was received the same result of precision which was compared RF wireless modem system.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2009.11a
• /
• pp.7-10
• /
• 2009

지상파디지털멀티미디어방송(Terrestrial-Digital Multimedia Broadcasting: T-DMB) 시스템 수신기는 이동 환경에서 방송신호의 원활한 수신을 요구한다. 따라서, 일정 레벨 이상의 전계강도와 단일 주파수 망(Single Frequency Network: SFN) 구축을 반드시 요구하게 된다. 본 논문에서는 단일 주파수 망을 통해 T-DMB 신호를 서비스하기 위해 설치하고 있는 등화형 T-DMB 동일채널 중계기(Equalization-Digital Multimedia Broadcasting On-Channel Repeater, E-DMBR)의 성능 및 신호 품질을 측정하기 위한 T-DMB RF 신호 모니터링 장비(T-DMB Monitoring System : DMR)에 대한 요구사항을 고찰하고, 그러한 요구사항을 만족하기 위한 모니터링 장비의 구조 및 구현 방법을 제안하며, 이를 이용한 개발 사례에 대한 결과를 보인다.