• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.10 s.101
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• pp.973-981
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• 2005

A modified half wavelength loaded line antenna is designed and implemented for mobile terminal applications. The antenna is constructed with a radiating element of half wavelength loaded line structure, dielectric substrate, feeding post and two shorting posts on the experimental PCB. The shorting posts are located at each side of the radiating element and lumped inductance elements are on between each shorting post and ground of PCB. By controlling value of inductors, one can adjust resonant frequency and input impedance respectively. Within inductance value of 12 nH, the antenna can have wide operating range of $1,470\~2,660\;MHz$ and good impedance matching. The measured peak gains are between -0.45 dBi and 2.03 dBi for the operating band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.265-272
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• 2007

In this paper, a frequency changeable antenna using dual half wavelength loaded line structure is proposed for multiband mobile handset applications. The proposed antenna has a capability of independent frequency shift by controlling two added inductance values in two different bands. Experimental results indicate that the proposed antenna provides enough effective bandwidth to cover $CELLULAR(824\sim894\;MHz)$, $EGSM(880\sim960\;MHz)$, $DCS1800(1,710\sim1,880\;MHz)$, $PCS1900(1,850\sim1,990\;MHz)$ and $WCDMA(1,920\sim2,170\;MHz)$ bands and peak gain variation is only 0.54 dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.12 s.103
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• pp.1179-1185
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• 2005

In this paper, novel internal antenna with its controllable resonant frequency is presented for triple-band or over mobile handsets. The operating range can include GSM(880${\~}$960 MHz), GPS(1,575$\pm$10 MHz), DCS(1,710${\~}$1,880 MHz), US-PCS(1,850${\~}$l,990 MHz), and W-CDMA(1,920${\~}$2,170 MHz). The proposed antenna is realized by combination of a half wavelength loaded line and a shorted monopole. A single shorting and feeding points are used and they are common to both antenna structures. By controlling a value of lumped inductance element between shorting point and ground plane, the antenna provides enough bandwidth to cover DCS, US-PCS, and W-CDMA respectively. When these higher bands are controlled by the values of inductance, resonant characteristics in GSM and GPS bands are maintained. In this work, maximum value of the inductor is limited within 3.3 nH to mitigate gain degradation from frequency tuning. As a result, measured maximum gain of antenna is -0.58${\~}$-0.30 dBi in the GSM band, -0.57${\~}$0.43 dBi in the GPS band and 0.38${\~}$1.15 dBi in the DCS/US-PCS/W-CDMA band. In higher band, the proposed antenna is certified that resonant frequency of about 240 MHz can be effectively controlled within gain variation of about 0.77 dB by simulation and measurement.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.2
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• pp.50-55
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• 2008

In this paper, multi-band internal antenna which can adjust both resonant frequency and input impedance of antenna as using lumped inductor between shoring plate and ground plane is proposed. The structure of proposed antenna consists of PIFA (Planar Inverted F Antenna) structure and half-wavelength loaded line structure and has two shorting plates and one feeding plate. One shorting plate is shared. The operating frequency bands of designed antenna are GSM, GPS in the PIFA structure and DCS, US-PCS, W-CDMA in half-wave loaded line structure as varying the inductor value in 2.2nH, 3.3nH, and 4.7nH. As varying the inductor value in the shared shorting plate, input impedance of antenna is varied. To minimize the gain variation of antenna as adding lumped element, the inductor value is restricted at maximum of 6.8nH. The maximum gain of proposed antenna is measured as -1.60dBi in the GSM band, -1.16dBi in the GPS band, and 1.41dBi in the DCS/US-PCS/W-CDMA band.

• Journal of electromagnetic engineering and science
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• v.2 no.1
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• pp.45-49
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• 2002

This paper presents the basic characteristics of a forced resonant type EMI dipole antennas for frequencies below 80 MHz in which two reactance elements are used for the impedance matching at the fined point. The input impedance of the short dipole less than half-wavelength is controlled by the properly determined loading position and the value of loading reactance. The numerical results show that the small-sized EMI dipole antenna with loller antenna factors for frequencies below 80 MHz can be realized by the reactance loading. In case tole proposed center driven forced resonant type EMI dipole antenna with 0.3 λ length is loaded from the center, the input impedance is matched at feed line with 50 $\Omega$, and hence the antenna has lower factors in the frequency range of 30 to 80 MHz.

• Journal of the Korea Society of Computer and Information
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• v.15 no.8
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• pp.59-66
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• 2010

In this paper, the internal antenna for mobile communication handset which is able to control both coupling coefficient and resonant frequency without any major modification of radiator and ground plane of antenna. Novel internal antenna with its controllable resonant frequency is presented for triple-band or over mobile handsets. The operating range can include GSM(880~960 MHz), GPS($1,575{\pm}10MHz$), DCS(1,710~1,880MHz), US-PCS(1,850~1,990 MHz), and W-CDMA(1,920~2,170 MHz). The proposed antenna is realized by combination of a half wavelength loaded line antenna and PIFA(Planner Inverted F Antenna). A single shorting and feeding points are used and they are common to both antenna structures. One of two inductors which is placed at each shorting post, one inductor is for adjusts amount of coupling, and the other controlling the resonant frequency in DCS/US-PCS/WCDMA bands. The inductance range for control of input impedance is between 0nH and 6.8nH, and each of gain variation in GSM, GPS and DCS/US-PCS/WCDMA band is under 0.15dBi, 0.73dBi and 0.29dBi. The inductance range for control of the resonant frequency is between 1640MHz and 2500MHz, and each of gain variation in GSM, GPS and DCS/US-PCS/WCDMA band is under 0.46dBi, 0.53dBi and 0.8dBi.