• ETRI Journal
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• v.27 no.6
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• pp.697-707
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• 2005

This paper proposes a new design of directional couplers with high directivity for personal communication services (PCS) and International Mobile Telecommunications-2000 (IMT-2000). The directional coupler is used to check and verify the power, frequency, and antenna reflection of a signal at transmission stations for mobile communications. The performance requirements of directional couplers are a strong coupling to reduce the effect on the transmitted power and high directivity to suppress the interference of the reflected signals and reduce the errors in communication. So far, various architectures have been proposed to gain high directivity, and there have been many studies used to obtain a strong coupling. However, conventional architectures for high directivity and strong coupling have a directivity of only about 20 dB, and there have been difficulties to achieve the higher directivity of 30 dB suitable for PCS and IMT-2000. This paper proposes a new architecture of directional couplers based on a grounding composed of strip lines, and compares the test results of this directional coupler with conventional ones. The results show that the proposed directional coupler has a directivity of more than 30 dB and is adequate for PCS and IMT-2000.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.3
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• pp.242-250
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• 2004

In this thesis, a new broadband PIFA(Planar Inverted-F Antenna) for PCS and IMP-2000 applications is designed. The dual-L antenna structure is adopted in order to improve the characteristics of PIFA which usually has a narrow band. The height of the antenna is fixed 6 mm considering terminal's thickness and the structure is deformed into the folded radiation patches to minimize the size of the antenna. The bandwidth of a realized antenna is 1.66∼2.35 ㎓(34.5 %) fur return loss below -10 ㏈ which contain the required bandwidth of PCS and IMT-2000. And Monopole antenna with λ/4 length is designed and compared with dual-L with folded patch in SAR. 1 g and 10 g averaged peak SAR of PIFA are about 25.7 %, 30.3 % lower than those of monopole antenna respectively.

• Journal of the Korea Society of Computer and Information
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• v.7 no.3
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• pp.99-108
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• 2002

Users location management and handoff management is constructed more effective for giving satisfaction to QoS of multimedia service in Mobility network. For this, We have the HLR of IMT-2000, difference of the HLR of PCS, and connectivity Artificial Intelligent network and to provide data service of packet that is analyze to effect on the HLR. We have a study on effective for satisfaction of QoS, that is the VHE of full concepts for provide of service in the IMT-2000, packet data service for internet connectivity, for satisfaction of QoS on basis mobility network technologies of the 2nd generation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.337-340
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• 2001

In this paper, we propose two types of dual-mode voltage controlled oscillators (VCO) for PCS/IMT-2000 applications. One is a VCO with controllable resonant circuit. The other type is a VCO with single output and two independent parts

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9B
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• pp.1579-1587
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• 2000

This paper presents the properties of the RF part in the receiving system based in IMT-2000 terminal technology. It mainly discuss the RF parameter performance of the receiving system for mobile telecommunication comparable to IS-98A and J-STD-018 specifications of commercially available CDMA and PCS, and is to anticipate the processing gain of the IMT-2000 receiving system, processing gain according to data processing rate, and terminal noise figure according to processing gain, relationship between noise figures according to Eb/Nt, Ioc. It is performed by such analysis method as CDMA and PCS receiving systems. Transmission bandwidth is n$\times$1.25 MHz(n=1, 3, 6, 9, 12) which is recommended by Qualcomm and NTT, the leading company in cdma 2000. Data transmission rate of IMT-2000 is classified into three cases as in moving vehicle environment of 144Kbps, outdoor pedestrian environment of 384Kbps, and indoor office environment of 2Mbps

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.6
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• pp.996-1005
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• 2000

This paper proposed a novel broadband ceramic dielectric antenna by improving the conventional broadband technique that very high permittivity material is attaching to one side of low permittivity material. The broadband ceramic dielectric antenna can be designed by using our proposed method, and it overcomes the disadvantage of narrow bandwidth problem. For the proposed ceramic dielectric antenna, a 10 dB return-loss bandwidth of 33.9% has been achieved. The measurement and numerical results(Finite Element Method) are performed and confirmed to a good agreement with each other. The proposed ceramic dielectric antenna is designed and implemented to extend enough the coverage of dual band (PCS+IMT-2000).

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.7
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• pp.24-30
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• 2000

In this paper, we proposed an fiber-optic transceivers based on the analog optical transmission techniques of incorporating the SCM (subcarrier multiplexing) and WDM (wavelength-division multiplexing ) method, which can be used to transmission of IMT-2000 and PCS wireless frequency band and analyzed overall those parameters related with fabrication. Especially in the impedance matching network between RF signal and LD, we proposed the method of deriving optimal performance using simulation techniques. In the frequency band of 1.7GHz∼2.25GHz, experimental data for the gain flatness and the noise floor of the optical link were also presented $\pm$1.5dB and -130dBm respectively when the link Rain was 0dB.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.2
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• pp.190-195
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• 2003

We developed a loading sleeve for Automobile, which has the PCS and IMT-2000 frequency bands. The electric characteristics of the designed sleeve monopole has SWR<1.311 and 3.0dBi in average gain for that frequency bands. In this study, the designed sleeve monopole was installed at a roof and trunk lid of vehicle. The characteristics of designed sleeve monopole was investigated by measuring SWR, input impedance and radiation pattern. The experimental results show that the efficiency of the sleeve monopole is superior th that of domestic and foreign commercial PCS antenna.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.11
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• pp.93-98
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• 2003

In this paper, we designed a printed square loop antenna for operating of PCS and IMT2000 band. The proposed antenna has omni-directional radiation patterns with broad bandwidth, similar to the conventional antenna, to easy feed on composing single planar. We obtain an ideal impedance matching and increase bandwidth. An antenna bandwidth is about 150MHz(1.74∼l.89〔GHz〕) at 1$^{st}$ resonance frequency and 290MHz(1.95∼2.24GHz) at 2$^{nd}$ resonance frequency on VSWR(equation omitted)1.5, and then we can obtain not only 1.73∼l.87 〔GHz〕 PCS band but also 1.92∼2.17 (GHz) IMT2000 band. band.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.6
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• pp.1619-1626
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• 1998

In this paper, we made researches into considerations for the numbering plan for IMT-2000 that seems to be a unit system integrating cellular, satellite, PCS. The purposes of the numbering plane for IMT-2000 ARE SIMILAR TO IMT-2000 evolution form:constructing the numbering plane centering around UPT as a PRE-FPLMTS from and futhermore, adding terminal mobility to IMT-2000. For this paper, we established three numbering plans for IMT-2000 that accepts various considerations.