• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.12
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• pp.1337-1344
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• 2007

It is shown that inverted ${\pi}$ feeder affects the gain improvement for the internal antenna of mobile phone. Generation of current on the inverted ${\pi}$ feeder, by the modification of conventional feeding structure for the PIFA and IFA, can apply T matching theory to the new feeder. Therefore, inverted ${\pi}$ feeder based on the T matching theory makes higher radiation resistance, and also increases the gain. To verify inverted ${\pi}$ feeding effect, feeder is applied to GSM/DCS dual band conventional PIFA, and measured return loss and patterns. By measurement, it's shown that this new feeding antenna has $0.23{\sim}0.84$ dB higher average gain for GSM band and $0.01{\sim}1.74$ dB higher average gain for DCS band than conventional fed PIFA without resonant frequency change.

• Journal of Advanced Navigation Technology
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• v.13 no.5
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• pp.662-668
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• 2009

Design of IPI(Inverted PI) feeding internal antenna for the gain improvement of mobile phone was proposed. IPI feeding structure affects on both low radiation resistance of antenna and increase current for the internal antenna such as IFA(Inverted F Antenna). By these facts, antenna fed by IPI can get the gain improvement with increasing radiation efficiency. For the verification, we applied IPI feeding structure to conventional quad band IFA. Measurement shows that IPI-IFA has 0.3~2.0[dB] higher gain than conventional IFA on GSM/DCS/USPCS/WCDMA band.

• Journal of Advanced Navigation Technology
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• v.14 no.6
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• pp.817-823
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• 2010

Design of IPI feeding structure affecting the antenna gain improvement of mobile phone was investigated. IPI feeder which based on the T matching theory increase line current for internal antenna such as IFA. So IPI feeder makes higher radiation resistance, and also increases the gain with increasing radiation efficiency. To verify IPI feeding effect, feeder is applied to conventional CDMA/DCS dual band IFA. Measurement shows that IPI-IFA has 0.5 ~ 1.4[dBi] higher gain than conventional IFA at CDMA/DCS band. Resonant frequency did not change.