• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.4 no.1
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• pp.46-52
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• 2011

In the paper, MIMO antenna for LTE 13 band, LTE 7 band wireless communication service is proposed. The proposed antenna is designed where on the top of FR-4(${\epsilon}_r=4.4$, thickness=-.8mm). In proposed structure, two Planar Inverted F Antennas (PIFAs) using meander and folded structure are symmetrically designed for the miniaturization. The isolation between two antennas was also improved by using two slits on the ground plane. The isolation values of the fabricated antenna exhibits -18 dB, -13dB at LTE 13 and LTE 7 band, respectively. The average gain and efficiency are - 4.1 dBi, 41% on LTE 13 band, -1 dBi, 81% on LTE 7 band, respectively. Thus the proposed antenna can be applied to the LTE system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.9A
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• pp.900-905
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• 2006

In this paper, PIFA antenna for $2.40{\sim}2.482GHz\;and\;5.75{\sim}5.85GHz$ is designed, fabricated, and measured. The prototype consist of hair-pin and short-pin. To obtain suitable bandwidth, the form layer is inserted between ground plane and substrate. Important parameters in the design are hair-pin length, width, position, air-gap height, and feed point position. From these parameters optimized, a PIFA antenna is fabricated and measured. The measured results of the antenna are obtained as follows results. The resonant frequency of the fabrication PIFA antenna is 2.37GHz and 5.86GHz bandwidth for approximately 90MHz with 350MHz(VSWR<2.0) and the gain is $1.91{\sim}4.37dBi$. H-plan and E-plan at 2.4GHz and 5.8GHz are shown as $52.83^{\circ},\;85.90^{\circ}\;and\;68.68^{\circ},\;52.143^{\circ}$ respectively.

• Journal of Electrical Engineering and Technology
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• v.9 no.1
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• pp.273-279
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• 2014

Hexagonal Ba-ferrites are widely suggested as materials for small antennas. In this paper, the sintering behavior and magneto-electric properties of $Ba_3Co_{2-2x}Mn_{2x}Fe_{24}O_{41}$ ($0.1{\leq}x{\leq}0.5$) ceramics were investigated for small antenna application. All samples of $Ba_3Co_{2-2x}Mn_{2x}Fe_{24}O_{41}$ ceramics were prepared by the solid-state reaction method and sintered at $1250^{\circ}C$. From the XRD patterns of the sintered $Ba_3Co_{2-2x}Mn_{2x}Fe_{24}O_{41}$ceramics, the Z-type phases were found to be the main phases. The real part of permittivity and permeability of the $Ba_3Co_{2-2x}Mn_{2x}Fe_{24}O_{41}$ceramics decreased with frequency. On the other hand, loss tangents of permittivity and permeability tended to behave opposite to real part of permittivity and permeability. The real part of permeability was affected by Mn additions. The real part of permittivity, the loss tangent of permittivity and the real part of permeability, the loss tangent of permeability of $Ba_3Co_{0.2}Mn_{0.8}Fe_{24}O_{41}$ ceramics were 19.774, 0.176 and 15.183, 0.073, respectively, at 510 MHz. In order to investigate the effect of magneto-dielectric ceramics on antenna, PIFA (Planar Inverted F Antenna) was simulated with CST (Computer Simulation Technology). The operating frequency of antenna was decreased without considerable change of bandwidth by using the $Ba_3Co_{0.2}Mn_{0.8}Fe_{24}O_{41}$ ceramics as the carrier.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.2 s.117
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• pp.136-142
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• 2007

We present two effects of the case currents of a mobile phone on changing the radiation pattern of a PIFA and on enhancing the bandwidth of the monopole antenna. In order to change the radiation pattern, a modification of the ground plane is suggested to suppress the back radiation. The resulting gain is higher than that of a conventional PIFA by 0.5 dB. For enhancing the bandwidth, two parasitic metallic lines are added in the direction orthogonal to the monopole to induce double resonances. The impedance bandwidth of the proposed structure is 341 MHz, which is nearly twice of that of the conventional monopole.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.4
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• pp.477-483
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• 2008

The paper introduces mobile handset multi-band chip antenna to be used on meander line PIFA structure and parasite patch. The proposed antenna uses an FR-4 substrate. The top layer is consist of meander lines PIFA structure to implement GSM900 and is connected with each rad and meander line on the via-hole for maximize space efficiency. The middle layer is designed with the signal line and gap to implement a DCS and PCS bands, the bottom layer which is added to a parasite patch on the ground can be show an adjust of frequency and impedance character by the connection of the radiators of middle layer and coupling. The fabricated antenna with the dimension of $28{\times}6{\times}4\;mm^3$. The ground plane a dimension of $45{\times}90\;mm$, designed by a commercial software CST simulator. The experimental results show that the bandwidth for(VSWR<3) is 90($875{\sim}965$) MHz in GSM900 band operation and 380($1,670{\sim}2,050$) MHz in DCS, PCS band operation. The maximum gains of antenna are 0.25 dBi, 3.65 dBi and 3.3 dBi at resonance frequencies and it has omni-directional pattern practically.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.4
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• pp.768-773
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• 2010

In this paper, we study on an optimal design of a triple-band PIFA (Planar Inverted-F Antenna) of 433 MHz, 912 MHz and 2.45 GHz by using evolution strategy. Generally, the resonant frequency of the PIFA is determined by the width and length of a U-type slot used. However the resonant frequencies of the multiple U slots are varied by the mutual effect of the slots. Thus the optimal width and length of U-type slots are determined by using an optimal design program based on the evolution strategy. To achieve this, an interface program between a commercial EM analysis tool and the optimal design program is constructed for implementing the evolution strategy technique that seeks a global optimum of the objective function through the iterative design process consisting of variation and reproduction. The resonant frequencies of initial model are 439.5 MHz, 981.5 MHz and 2.563 GHz. However, the resonant frequencies of the triple-band PIFA yielded by the optimal design program are 430.5 MHz, 907 MHz and 2.4515 GHz. Measured resonant frequencies are 433.5 MHz, 905.5 MHz and 2.454GHz, which show a good agreement with the simulation results.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.11
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• pp.8-16
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• 2000

In this paper, on calculating SARs on human head using computer simulation, SARs caused by PCS handsets are calculated and compared, and the design parameters that affect SAR values are analyzed. Is and 10 g peak averaged SARs are calculated as the type of antenna, the location of antenna, and the type of handset are changed and SAR distributions as depth of human head are shown. Among the antennas on flip type handsets, side mounted PIFA has the lowest SARs 1g and 10g peak averaged SARs are 0.686W/kg and 0.353W/kg. The SARs caused by monopole antenna on folder type handset are 1.133W/kg and 0.709W/kg. and are about 30% lower than monopole 1.759W/kg and 0.978W/kg, respectively. SAR distributions as depth of human head of side mounted PIFA and monopole antenna on folder-type handset are more slowly changed than those of top mounted PIFA and monopole antenna on flip-type handset.

• 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.