• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.1
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• pp.90-97
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• 2010

In this paper, we propose antenna topology and ground plane shape to improve the performance of PIFA (Planar Inverted F Antenna) which is built-in mobile phone. First, we designed the PIFA antenna consists of multiple radiators to provide multi-current paths. Then we designed U-shaped ground plane on the PCB under the antenna. The proposed antenna structure shows TRP/TIS improvement of 2.0 dB/3.7 dB for GSM and 2.2 dB/ 2.0 dB for DCS and 0.8 dB/1.5 dB for PCS and 1.3 dB/0.7 dB for WCDMA at the free space.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.572-575
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• 2007

In this paper, we proposed a internal antenna for Quad band for GSM/DCS/USPCS/WCDMA Handset. Antenna Structure is designed to PIFA type. Antenna planed two independence patterns to reduce the size for efficiency and used shoting pin and inverse seven_type slit. Also they miniaturized the antenna construction electronic length for duty. furthermore, they designed and producted the antena height for 5w and ground term for 40*80mm. It is because they have wondered the thickness of terminal. used of for reduce size efficiently. The radiation pattern characteristic of antenna is compared and analyzed E-plane and H-plane at 920MHz, 1800MHz.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.4 no.1 s.6
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• pp.89-95
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• 2005

In this paper, a quad-band antenna for GSM/GPS/DCS/US-PCS handsets is proposed. The proposed antenna is low-profile for mounting in limited inner space of a handset. It consists of three open points with quarter wave length for multi-band operation. The ground plane below the patch is removed for wide-bandwidth without the variation of antenna size and the slot is added at the center of the patch for convenient matching in high frequency band. It provides a enough bandwidth within VSWR 3:1 at all bands. In addition, the measured peak gains are between -2.19 and 2.09 in anechoic chamber (10m$\times$6m$\times$4m).

• Journal of Internet Computing and Services
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• v.5 no.3
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• pp.63-72
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• 2004

Recently the range of mobile phone's usage has become more widely since phone has the function of data communication and voice communication. In addition, the request of users who wish to represent their identity on their mobile phones by storing some kinds of multimedia data such as images and melody has increased. There are two different methods for downloading the multimedia data; one method accesses a wireless internet server to download the data and another method downloads the data from PC directly. While the first one requires extra fee for downloading the data, the second method has weakness to modify the original data and it cannot be used in GSM phone yet since it is developed for CDMA phone. In this paper, we introduce a PC-based download application system that enables the users to download multimedia data from PC to GSM phone very easily.

• Journal of IKEEE
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• v.17 no.4
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• pp.484-491
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• 2013

In this paper, we proposed an internal multiband loop embedded monopole antenna for mobile handset that could be used for smart phones. The proposed antenna has a volume of 40 mm(W) ${\times}$ 15 mm(L) ${\times}$ 5 mm(H), ground plane size is 40 mm(W) ${\times}$ 80 mm(L), and covers the GSM900 (Global System for Mobile communications : 880-960 MHz), K-PCS (Korea-Personal Communications Service : 1750-1870 MHz), US-PCS (US Personal Communications Service : 1850-1990 MHz), WCDMA (Wideband Code Division Multiple Access : 1920-2170 MHz), Wibro (2300-2390 MHz), Bluetooth (2400-2483 MHz) and WLAN (Wireless Local Area Network : 2400-2483.5 MHz) bands for VSWR (voltage standing wave ration) less than 3. The proposed loop adding design at middle section of longest branch showed wide impedance bandwidth for the lowest resonance frequency band. The proposed antenna have a lowest resonance frequency band from 738 MHz to 1075 MHz for S11 value of -6dB. A HFSS (High Frequency Structure Simulator) of the Ansys Corporation based on a finite element method is employed to analyze the proposed antenna in the design process and to compare the simulation and experimental results.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.1002-1005
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• 2009

본 논문에서는 GSM/DCS/USPCS/WCDMA대역에서 사용할 수 있는 IFA 형태의 내장형 안테나를 설계하고 이를 제작하였다. 이 안테나는 제한된 공간에서 기본 IFA에 전류 흐름의 상쇄작용을 고려하여 4중 대역을 형성 시켰으며, GSM대역에서 Maximum Gain -1.11dBi ~ 1.29dBi, DCS/USPCS/WCDMA대역에서 -1.15dBi~3.12dBi의 결과를 얻었다. 방사패턴 또한 전방향성에 가까운 특성을 가지고 있으며 전체적으로 효율은 약 3.35% ~ 33.23% 향상됨을 확인할 수 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1330-1331
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• 2009

본 연구에서는 GERAN (GSM EDGE Radio Access Network) 망에서 다양한 무선환경에 따른 셀 재탐색을 연구하였으며, 시계열분석을 통하여 재탐색 이후의 RSS (Received Signal Strength)를 예측하여 개선된 재탐색 알고리즘을 연구하였다. Field 데이터를 통해 제안된 알고리즘을 분석하였으며, 이를 통하여 다양한 조건에 적합한 기법을 제안코저 한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.4
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• pp.470-476
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• 2008

In this paper, we describe the cause of TDMA noise and distinction method of TDMA noise source in a GSM mobile phone. The causes of TDMA noise are composed of RF(Radio Frequency) energy coupling and low frequency energy coupling by burst ripple. We propose the distinction method of TDMA noise source from output(TDMA noise measurement) and frequency response of a system(audio path). Especially we propose a method of insertion loss($S_{21}$) analysis and the improvement method for RF energy coupling. Capacitor(40 pF) is a solution to reduce RF energy coupling and therefore TDMA noise was reduced by 10 dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.9
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• pp.940-946
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• 2010

In this paper, we proposed the internal antenna on PCB(Planar Circuit Board) for achieving WWAN(Wireless Wide Area Network) operation in the laptop computer. The proposed antenna has a metal structure instead of printed pattern on PCB to improve the antenna characteristics for GSM850/900 bands. Compared to PCB embedded antenna without metal structure, the proposed antenna occupies similar area of $74{\times}11{\times}0.5\;mm^3$ with before and the bandwidth of the proposed one for GSM850/900 bands is increased 13 MHz than before. Further we confirmed that the proposed antenna has higher radiation gain of -4.45~-2.29 dBi for GSM850/900 bands than PCB embedded antenna without metal structure.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.7
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• pp.689-697
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• 2007

This thesis suggests ways on how to enhance handset radiation power under head phantom condition. Generally, peak EIRP(Effective Isotropic Radiated Power) is used to measure the radiation performance. TRP is more effective to represent indication of mobile radiation performance in the field than EIRP. In this case, we measure the TRP as an index of radiation power. The factors which effect TRP are antenna length, antenna position, folder angle and ground connection method. More detailed analysis is performed over these items. Significant item is ground connection method between main PCB and folder GND. Using the FPCB we connect main GND to folder GND through the hinge near the antenna. The result is that TRP attenuation is decreased about 5 dB under head phantom condition.