• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.315-318
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• 2001

We are proposing a new mobile phone antenna, which has a specially manufactured Mn-Zn cylindrical ferrite bead inside of the helical coil of the antenna. The extended antenna radiation patters and the spatial peak SAR averaged over 1 gram simulated tissue with and without the ferrite bead insertion were measured at 824 MHz. The results show that the ferrite bead resulted in SAR reduction about 20 %, and reflection coefficient increase about 7 % for the extended antenna. The applicability of this scheme to the antenna mass production is quite feasible.

• Journal of Advanced Navigation Technology
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• v.6 no.2
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• pp.113-118
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• 2002

In this paper, an internal GPS antenna for mobile phones is designed and fabricated. For the miniaturization of the antenna, high permittivity dielectric substrate((${\varepsilon}_r$=90) and small ground plane ($13mm{\times}13mm$) are used. To increase the receive gain, the antenna is composed with LNA(Low Noise Amplifier). Results of the manufactured antenna($13mm{\times}13mm{\times}8mm$) show that the maximum antenna gain is about 12 dBi, the axial ratio is less than 3 dB, and the current consumption of LNA is less than 4 mA.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.5
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• pp.43-49
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• 2008

Motivated by the Communication Broadcasting Convergence service, various technical approaches are being used to develop more efficient antenna models. This paper proposes a compact mobile antenna which is attachable to a cell phone and is applicable for Communication Broadcasting Convergence. In the design of the antennas for mobile handsets, size reduction is a crucial factor. In this paper, the compactness of a loop antenna is realized by bending a folded-dipole. A short planar dipole is transformed to a twice folded dipole and a loop antenna to produce a larger input resistance. The current distribution of the antenna is the same as a loop antenna, and its radiation patterns are omni-directional. We also analyze the performance of the RFID antenna by exploring the current-induced near field radiation patterns using a electro-optic field mapping system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.10
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• pp.1567-1570
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• 2022

This paper, we presents a RF protection technique of antenna switch by improving the power handling capability in worst case environment mode for mobile phone applications without critical payment of circuit performances such as insertion loss, isolation and ACBV (AC breakdown voltage). By applying a additional capacitive path located in front of the antenna in cell-phone, it performs the effective reduction of input power in high voltage standing wave ratio (VSWR) condition. Under the all-path off condition which causes a high VSWR, it achieved 37.7dBm power handling level as high as 5.7dB compared to that of conventional one at 2GHz. In addition, insertion loss and isolation performances were 0.31dB and 42.72dB at 2 GHz, respectively which were almost similar to that of the conventional circuit. The proposed antenna switch was fabricated in 130nm CMOS SOI technology.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.11
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• pp.1194-1200
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• 2009

An internal antenna which has 1 cc volume was implemented on the FPCB(Flexible Printed Circuit Board) for the mobile phone. We increased antenna gain and efficiency by the applying of current direction concept on the antenna pattern for this small antenna. Short antenna length for the GSM band was compensated by the spiral inductor on the FPCB. For broadening bandwidth on GSM band, it's applied 2 spiral inductors. A conductor pattern for the DCS band was positioned perpendicular with the FPCB. Antenna was implemented on FPCB that is dielectric constant 4.4 and thickness 0.05 mm, and FPCB was attached on a carrier dimensioned $L{\times}W{\times}H=30{\times}7{\times}5\;mm$. Measurements showed that max. VSWR 2:1, efficiency 42.49~60.95 % and 47.95~73.21 %, average gain -3.72~-2.15 dBi and -3.19~-1.35 dBi on the GSM and DCS band, respectively. These results are good performances among the small antenna. And the radiation patterns are omnidirectional on the H-plane to both band.

• Journal of Advanced Navigation Technology
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• v.15 no.2
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• pp.197-203
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• 2011

A triple-band antenna which can be used at GSM900, PCS1900 and Bluetooth(or Wi-Fi) frequency band is proposed. The proposed antenna is designed based upon switching between IFA(Inverted F Antenna) that has a resonant length of ${\lambda}/4$ and loop antenna that has a resonant length of ${\lambda}/2$. It can be applied to triple-band only by use of single printed pattern due to the switching characteristic. It is designed by use of the IFA for the application to the GSM900, while it is designed by use of the loop antenna for the application to the PCS1900 and by use of additional pattern of IFA for the application to the Bluetooth(or Wi-Fi) respectively. As a result, it has been observed that the proposed antenna satisfies the required return loss(${\leq}10dB$) and also has efficiency(${\geq}80%$) over the whole band. Moreover the proposed antenna has omni-directional radiation pattern which is suitable to apply to the mobile phone.

• Fire Science and Engineering
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• v.26 no.2
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• pp.11-16
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• 2012

In this paper, we analyzed damage patterns of a folder type mobile phone caused by microwave-irradiation, to find an accurate fire cause and to investigate deliberate broken of mobile phone for obtaining pecuniary advantage by deception. In order to analyze broken patterns, we irradiated a mobile phone with microwave using by 2.45 GHz microwave oven. Form the experiment results, damage patterns of mobile phone have been tendency toward heavy broken patterns depending on time of microwave-irradiated. Distinctively, folder hinge and intenna(Planar Inverted-F Antenna) were heavy broken in compare with battery, enclosure and so on. The enclosure of mobile phone became just thermo-metamorphism and the battery was not broken such as explosion.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.9
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• pp.881-887
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• 2011

In this paper, we proposed vertically structured radiator for increasing bandwidth and gain of mobile phone internal antenna. The proposed antenna has vertically structured radiator instead of planar structured radiator to improve the antenna characteristics for GSM850/900 and DCS1800/PCS1900 bands. The antenna improve bandwidth of low band with 28 % than planar structured radiator. and also, improve bandwidth of high band with 14 %, efficiency 31.80~86.36 %, average gain -4.956~-0.617 dBi on the GSM850/900 and DCS1800/PCS1900 bands. These results are good performance among the small antenna with vertically structured radiator for increasing bandwidth and gain.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.6
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• pp.706-713
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• 2010

In this paper, the small loop antenna with a parasitic loop structure for penta-band mobile phone application is proposed. This antenna is composed of a feed monopole, a radiating loop antenna with a parasitic loop structure and an additional radiating element. The antenna is printed on the very thin flexible substrate to mount on the dielectric carrier with a volume of 40 mm$\times$11 mm$\times$3 mm. The bandwidth of the proposed antenna is 402 MHz(773~1,175 MHz) for low band and 583 MHz(1,622~2,205 MHz) for high band. As a result, the proposed antenna covers the five bands of GSM850, GSM900, DCS1800, PCS1,900 and WCDMA for a 3:1 VSWR. Moreover, the radiation pattern, gain and efficiency are appropriate for mobile handset. Therefore, this antenna is suitable for small sized multi-band mobile handset applications.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.254-257
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• 2003

본 논문에서는 휴대폰에 사용되는 Multi-band 용 helical antenna 의 radiation pattern 을 체적화하기 위한 방법을 제안하고자 하였다. 일반적으로 GSM 휴대폰에 사용되는 안테나는 GSM, DCS 의 dual band 인 경우가 다수이며 추세에 따라 요즘은 PCS 등을 포함한 triple band 의 안테나가 많이 선호되고 있다. 이러한 multi band antenna 의 radiation pattern 에 영향을 미치는 변수로 본 논문에서는 ground 의 length 와 width 그리고 폴더쪽에 사용되는 LCD 의 ground 와 폴더쪽 기구물에 사용된 EMI spray 등의 변화를 통해 pattern 의 변화를 알아보고 이러한 변수를 조절하여 radiation pattern을 최적화하는 방법에 관하여 논하였다.