• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.455-457
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• 2000

3세대 통신망인 IMT-2000 서비스의 가장 큰 특징은 단말 이동성, 개인 이동성 및 서비스 이동성으로 구분되는 강력한 이동성의 제공이다. 이 중 서비스 이동성은 IMT-2000 서비스의 가장 큰 특징으로 가상 홈 환경(VHE ; Virtual Home Environment) 개념을 이용하고 있다. VHE는 개인 단말사이, 망 경계를 뛰어넘는 개인 서비스 환경 이동성의 개념으로 글로벌 로밍의 환경에서 서비스 가입자에게 Visited 망에서도 Home 망의 서비스를 그대로 이용할 수 있도록 하는 개념이다. 이 VHE에서 핵심이 되는 것이 프로파일을 어떻게 관리하여 사용자에게 원활한 서비스를 제공할 것인가 하는 것인데, 본 논문에서는 VHE 서비스를 위한 사용자 프로파일(User Profile), 서비스 프로파일(Service Profile), 단말 프로파일(Terminal Profile), 네트워크 프로파일(Network Profile)에 대한 관리 방법을 사용자 프로파일이 Home 망과 Visited 망에 위치하는 방법에 따라 시나리오에 적용하여 각 프로파일 정보를 교환하는 방법을 기술하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.226-230
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• 2000

In this paper, we implemented the QPSK demodulator with a CPLD chip, and examined the results. DD(Decision Directed)-Gardner algorithm is used for STR loop and Decision-Directed algorithm is used for CPR loop. The speed of the QPSK demodulator implemented in FLEX10K chip can be guaranteed approximately 2[Mbpsl] transmission speed. In practical designed by ASIC, the speed is faster than that of CPLD by 5-6 times.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.2
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• pp.374-379
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• 2010

In this paper, we have mathematically analyzed lumped element type negative group delay circuit (NGDC) and derived general design equation. The applicability of the proposed design equation is validated with mathematical and circuit simulation as well as with experimental results for intentional mobile telecommunication 2000 (IMT-2000) downlink band. As a design example, single branch NGDC with -0.8ns of group delay (GD) for narrow bandwidth of the specific frequency is simulated and fabricated. Finally, $\pi$-network NGDC is proposed and validated to obtain wideband GD response of $-1.7{\pm}0.06$ nsec for 60 MHz.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9B
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• pp.1511-1517
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• 2000

A new slot-coupled back-to-back microstrip array antenna is proposed for using in the IMT-2000 base station or repeater antenna. This antenna is composed of symmetrical SSAIP(Strip Slot, Air Inverted Patch) It has bidirectional radiation pattern in horizontal plane and 22.5$^{\circ}$main beam squint in vertical plane. The analysis is based on the cavity model and the design is achieved using Ensemble. Experimental results for the radiation pattern and the return loss have shown that the direction of the main beam is about 21$^{\circ}$and the impedance bandwidth is approximately 22.9% Thus the proposed antenna is able to operate over both uplink and downlink frequencies in IMT-2000.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.377-382
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• 2000

Film bulk acoustic resonator (FBAR) using AIN reactively sputtered at room temperature was fabricated. The FBAR is composed of a piezoelectric aluminium nitride thin film, top electrode of Al and bottom electrode of Au connected by a short (200${\mu}{\textrm}{m}$) transmission line on both sides and reflector layers of SiO$_2$- W Pair. The active areas of Al and Au were patterned using 150${\mu}{\textrm}{m}$ diameter shadow mask. The series resonance frequency (fs) and the parallel resonance frequency (fp) were measured at 1.976 GHz and 2.005 GHz, respectively. The minimum insertion loss and return loss were 6.1 dB and 37.19 dB, and the quality factor (Q) was 4261.

• Information and Communications Magazine
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• v.15 no.11
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• pp.64-76
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• 1998

• Information and Communications Magazine
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• v.15 no.11
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• pp.88-99
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• 1998

• Information and Communications Magazine
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• v.19 no.6
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• pp.98-111
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• 2002

• The Magazine of the IEIE
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• v.25 no.10
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• pp.32-42
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• 1998

• The Magazine of the IEIE
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• v.25 no.10
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• pp.43-51
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• 1998