• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.1
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• pp.60-67
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• 2002

In this paper, the dual band VCO of mobile communication terminal using oscillation part switching circuit is proposed. In order to model the VCO accurately, the resonator is converted the equivalent circuit which is analyzed to use numerical method and designed optimal the dual band VCO operating GSM and DCS band. In order to demonstrate the objective theory of the proposed VCO, the dual band VCO is designed and experimented. The results of experiment, it is conformed that the VCO can be used mobile communication hand phone and components of three generation mobile communication systems.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.171-174
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• 2011

In this paper, transformed IFA design is proposed to improve the antenna gain of GSM/DCS/PCS band. New antenna structure has been approved to be more convenient matching in the mobile phone terminal and increase gains and expansion bandwidth through the simulation and real measurement. According to measurement, it's shown 1.57dB higher average gain than conventional IFA.

• Proceedings of the KAIS Fall Conference
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• 2005.05a
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• pp.163-165
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• 2005

본 논문에서는 GSM/DCS/USPCS 대역에서 사용할 수 있는 PIFA 형태의 내장형 안테나를 설계하고 이를 제작하였다. 이 안테나는 제한된 공간에서 기본 PIFA에 적절한 슬릿을 구성하여 트리플 밴드를 형성 시켰으며, GSM 대역에서 Maximum Gain -3.25dB$\~$6.37dB, DCS 대역에서 Maximum Gain -0.46dB$\~$2.95dB의 결과를 얻었다. 방사패턴 또한 전 방향성에 가까운 특성을 가지고 있으며 현재 GPRS용 휴대폰에 적용시키고 있다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.8 s.99
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• pp.783-789
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• 2005

In this paper, a novel design and implementation of a dual-band directional coupler based on RF IPD(Integrated Passive Device)-on-glass technology is proposed, which can be adopted in GSM/GPRS cellular phones for closed loop power control at the output of the power amplifier. The proposed coupler has a compensation capacitor to improve the directivity, and was designed using a new diplexing structure to minimize the cross-band isolation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.8 s.111
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• pp.713-718
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• 2006

We designed and fabricated, in this paper, a quintuple band folded monopole antenna for the mobile phone handset that can be provided multiple mobile services. Antenna design was based on the compensation of series antenna capacitance with the expansion of physical antenna length by the proper folding structure. It's shown that this antenna satisfies quintuple service band as CDMA/GSM/DCS/USPCS/WCDMA, and is more cost competitive than conventional metal plate pressing method by applying on flexible PCB technology. Measured maximum gain on quintuple band were $-2.51{\sim}+1.82 dBi$, and radiation patterns were also shown nearly omnidirectional on all bands.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.9 s.100
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• pp.917-925
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• 2005

In this paper, the quad-band antenna for mobile handsets is proposed and developed. The operating frequency bands include GSM(880 MHz${\~}$960 MHz), GPS(1,575 MHz$\pm$10 MHz), DCS(1,710 MHz${\~}$l,880MHz), and PCS(1,850 MHz${\~}$l,990 MHz). The proposed antenna consists of a feed line, a shorting post, and a radiating element of the feed loop. The multi-band operation is achieved by using the fundamental and higher resonant modes of the radiating element. Based on analysis of the current distribution on the radiator, the resonant frequency of each mode can be adjusted by adding the different sizes of slots on the radiator. The radiator of the feed loop is designed to be symmetrical so that the energy is symmetrically distributed on the radiator, which results in omni-directional radiation pattern. The ground plane under the radiator is removed in order to improve the bandwidth. The measured impedance bandwidths are $10.1\%$ in GSM band(VSWR<2.5), $26.8\%$ in GPS band, and DCS/US-PCS bands(VSWR<2.5), respectively. The maximum gains on the H-plane of the fabricated antenna are measured about -0.37 dBi${\~}$2.55 dBi for all operating frequency bands.

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.3
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• pp.219-222
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• 2007

In this paper, we have designed microstrip antenna of 800[MHz] band. It will be able to integrate TRS(Trunked Radio System), GSM(Global System for Mobile telecommunication) band including the CDMA(Code Division Multiple Access) band. we designed repeater and a base station antenna which is possible at the ship and marine of safety. It is improves a narrow bandwidth problem of microstrip antenna. It had L-shaped feeding structure at a rectangular patch and added the parallel L-slot that used a duplex resonance effect. Also for the improvement of profit the stack with the perpendicular. Designed frequency bandwith(VSWR 2:1) of the antenna showed good characteristic of 789${\sim}$1046[MHz] to 292[MHz](36%). Also the E-plan and H-plan all profit 6.4[dBi] above, the 3[dB] beam width showed the characteristic over the E-plan $44.7^{\circ} and H-plan $61.8^{\circ} to be improved.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.5
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• pp.185-189
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• 2005

This paper focuses on the design for Rx/Tx switch module of GSM(global standard mobile) band, characterization of a miniature, low power and dual-band implementation of the front-end switch module with low-pass filer And the effort to make agreement between the simulated design and the measured data for these solutions takes the place through accumulated design and manufacturing data library. We present the design, modeling and measurement of switch module integrating GSM Rx/Tx switching circuit and LPF(low pass filter) on a LTCC(low temperature co-fired ceramic) substrate. For GSM application, insertion and return loss of the low pass filter designed was less than 0.3 dB which was less than 12.7 dB at 900 MHz. The LTCC switch module contained 10 embedded passives and 3 surface mount components integrated on 4.6$\times$4.8$\times$1.2 mm, 6-layer multi-layer integrated circuit. The insertion loss of switch module measured at 900 MHz was 11 dB. In both of the design approach yielded excellent agreement between measured and simulated results.

• Journal of information and communication convergence engineering
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• v.6 no.2
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• pp.169-171
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• 2008

An internal antenna for small mobile systems is proposed to support the DVB-H system. It consists of two antenna elements, which are a folded planar monopole for DVB-H and PIFA for GSM/DCS/PCS, and a meander line and RF cable are used to increase the ground plane. Experimental results of the antenna are presented.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.334-337
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• 2003

GSM / DCS1800 / PCS 대역에서 사용 가능한 9.5mm x 6.5mm 크기의 트리플 밴드 초소형 전압제어 발진기를 설계하였다. 설계된 트리플 밴드 VCO는 GSM(880∼915MHz) 대역에서 7±3dBm의 출력전력, DCS1800 (1720∼1785MHz) 대역에서 8±3dBm의 출력전력, PCS(1720∼1780MHz) 대역에서 0±3dBm의 출력전력의 특성을 보인다. 위상 잡음의 특성은 -110dBc @100KHz 이하의 만족할만한 성능을 보인다.