• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.11
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• pp.1101-1110
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• 2011

This paper presents a printed, wideband folded monopole antenna for laptop and tablet computer applications. The proposed antenna is designed to cover bandwidth(2.3~10.6 GHz) of Bluetooth, WiMAX, and UWB system by using the printed folded monopole antenna having asymmetrical line width coupling with a parasitic inverted- L element. Also, wireless LAN band(5.15~5.85 GHz) which interferes with UWB system is rejected by inserting half-wavelength open stub in the folded monopole antenna. -10 dB bandwidth of the fabricated wideband antenna is 2.27~10.6 GHz (4.7:1) and -10 dB band-rejected bandwidth is measured as 700 MHz(5.15~5.85 GHz, 12.72 %). The gain and efficiency of the antenna except for the rejected band are higher than 3.93 dBi and 91.89 % and are measured as -2 dBi and 14.65 % at 5.5 GHz which is band-rejected frequency. The size of the antenna is suitable to install for small space of tablet and laptop computers as 12.75(1 ${\lambda}$/10)${\times}$12(1 ${\lambda}$/11) $mm^2$(${\lambda}$ is free space wavelength at 2.3 GHz). Therefore, we verified that the designed antenna is appropriate for wideband antenna of tablet and laptop PC applications.

• Journal of Navigation and Port Research
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• v.28 no.1
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• pp.31-36
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• 2004

In this paper, the characteristics of an inverted-F antenna for the 2.4GHz(ISM) Bluetooth system have been analysed in terms of the variation of design parameters. The antenna can be integrated on printed circuit board, and the characteristics in terms of the variation of the gap between feed line and shorting stub, gap between antenna's leg and ground plane, antenna leg's width, substrate's height and dielectric constant are analysed By using these characterization plot of design parameter, the tuning techniques are proposed to design optimum antenna. The designed antenna has 6.3%(150MHz) frequency bandwidth for VSWR under 1.5, and 3dBi gain.

• Journal of Advanced Navigation Technology
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• v.20 no.1
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• pp.99-106
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• 2016

Wearable display market is a consistently growing field to handle a smart device with ease. Wearable display is an efficient device that can show the information to the user. In this paper, propose the scheme of a wearable display using LED and implement it including controlling remotely with BLE. Traditional outdoor LED display requires the dedicated controller and its software. Therefore, to control those LED display, it should implement a driver and its own way of communication. The proposed method is to ensure the independence and extensibility by separating driver module and communication module for controlling LED display. In addition, by adopting a short-range communication with Bluetooth 4.0 and a LED driver with low-power technology, it can be showed to control system configuration and display with a smart device.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.1004-1007
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• 2005

This paper presents a programmable RF BIST (Built-in Self-Test) circuit for low noise amplifiers. We have developed a new on-chip RF BIST circuit that measures RF parameters of low noise amplifier (LNA) using only DC measurements. The BIST circuit contains test amplifier with programmable capacitor banks and RF peak detectors. The test circuit utilizes output DC voltage measurements and these measured values are translated into the LNA specifications such as input impedance and gain using the mathematical equations. Our on-chip BIST can be self programmed for 1.8GHz, 2.4GHz and 5.25GHz LNA for GSM, Bluetooth and IEEE802.11g standards.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.11
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• pp.89-94
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• 2007

For successful implementation of multi-standard transmitter, reconfigurable architecture and component design are essential. This paper presents a reconfigurable CMOS power amplifier designed CMOS 0.25 um process. Designed power amplifier can be operated at 0.9, 1.2, 1.75, and 1.85 GHz. Also, it can be used at 2.4 GHz by using bonding wire inductor. The interstage matching network is composed of two inductors and four switches, and operation frequency can be varied by controlling switches. Proposed power amplifier can be used as a power amplifier in low power applications such as ZigBee or Bluetooth application and used as a driver amplifier in high power application such as CDMA application. Designed power amplifier has 18.2 dB gain and 10.3 dBm output power at 0.9 GHz. Also, it represented 10.3 (18.1) dB gain and 5.2 (10) dBm output power at 1.75 (2.4) GHz.

• TTA Journal
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• s.68
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• pp.100-107
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• 2000

일상생활과 사무실에 거센 바람이 불고 있다. 그것은 근거리 무선접속규격의 신기술인 블루투스(Bluetooth)로서 우리의 모든 생활을 바꾸어 놓을 것이다. 인류의 역사를 바꾸는 신기술인 IMT-2000과 더불어 블루투스가 각광을 받고 있는 시점이다. 일상생활에서 특히 가정과 사무실에서 근거리 무선접속 구간에서의 이동성을 가진 디바이스들 간 상호통신의 새로운 표준으로 자리잡고 있다. 이와 같이, 일상생활에서의 커다란 변화와 산업 정보화시대에서 가장 큰 관건은 정보 고속화와 정보의 정확한 전달일 것이다. 이러한 것과 발맞추어 진행 중인 것이 근거리 무선구간에서의 2.4GHz대 ISM(Industrial, Scientific, Medical) 대역의 주파수를 사용하여 1Mbps 속도(실효속도 721K)로 최대 10m내에서 각종 단말기와 디바이스(예: 전화기, Fax, 데스크 탑, 노트북 컴퓨터, MP3 플레이어, 스캐너..)들을 무선 접속하는 블루투스 기술이며, 이는 기존의 유선에서의 불편함을 깔끔히 해소해 주었다. 필자는 전반적인 블루투스의 흐름을 간략하면서도 필요한 부분을 전달하는 목적으로, 또한 아직 블루투스의 위력을 인식하지 못한 기업과 독자들에게 새롭게 인식할 수 있도록 블루투스의 소개와 함께 기술적인 측면, 시스템적인 면과 회사별 제품현황에 대해 중요한 부분만을 블루투스 스팩을 기준으로 정리하였다.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.3
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• pp.260-264
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• 2008

In this paper, a dual mode baseband analog channel selection filter is described which is designed for the Bluetooth and WCDMA wireless communications. Using the presented current-mode integrator, a dual mode channel selection filter is designed. To verify the current-mode integrator circuit, Hspice simulation using 1.8V Hynix $0.18{\mu}m$ standard CMOS technology was performed and achieved $50.0{\sim}4.3dB$ gain, $2.29{\sim}10.3MHz$ unity gain frequency. The described third-order dual mode analog channel selection filter is composed of the current-mode integrator, and used SFG(Signal Flow Graph) method. The simulated results show 0.51, 2.40MHz cutoff frequency which is suitable for the Bluetooth and WCDMA baseband block each.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.7 no.3
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• pp.142-146
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• 2014

In this paper, an antenna which has quad band in GSM/DCS/PCS/Bluetooth is proposed. This structure is designed with miniaturization for wide band characteristic based on monopole antenna and log-periodic toothed trapezoid patch antenna which has slots. To achieve multi-bandwidth is used the microstrip line on the substrate. An antenna size is $35mm{\times}20mm$ on FR-4(${\varepsilon}r=4.4$) ground substrate of $35mm{\times}75mm{\times}1mm$ size. And proposed antenna is satisfied with impedance bandwidth(VSWR ${\leq}$ 3). The simulated maximum radiation gain is 1.92 dBi, 3.26 dBi, 3.97 dBi at the center frequency of 0.92 GHz, 1.97 GHz, 2.45 GHz, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.2
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• pp.295-300
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• 2005

In this paper we have designed a two-stage Class I power amplifier operated at 2.4CHz for Class-1 Bluetooth application. The power amplifier employs class-I topology to exploit its soft-switching property for high efficiency. The latch-structured pre-amplifier with amplifiers makes its output signal as sharp as possible for soft switching of the next power amplifier. It improves the overall efficiency of the proposed power amplifier. It shows 65.8$\%$ PAE, 20dB power gain and 20dBm output power.

• Journal of information and communication convergence engineering
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• v.8 no.5
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• pp.586-590
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• 2010

Medical technology is gradually being developed by applying information technologies. Especially, RFID technology is being used for precise disease history information of patients [4]. And in case the patient is far away, the patient can be treated using network communication of the internet [5][6]. The internet makes us to treat or operate the patient without being restricted to time or space. If the above technologies are made as a system, the patient can be treated or operated without being restricted to time or space. In this paper, we present a patient treatment system has been implemented with a system using RFID and network communication of the internet [1][2][3][4]. The system is driven as follows. First, the information of patient can be checked from a remote PC, if the tag that a patient has been read through a reader. And a remote treatment is performed by controlling robot's arm with a joystick using internet network [19][20][21]. The RFID system was implemented in frequency of 125 KHz [1]. The information of patient can be checked with PDA, PC and C-LCD using Bluetooth and WLAN [7][8][9][10]. For the treatment and operation of the patient, the robot's arm has been formed using AX-12 motor, joystick and two buttons [11][12][13][14][15] [17][18].