• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.5
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• pp.105-113
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• 2009

In this paper, a vehicle antenna for AM, FM, TDMB, GPS systems was designed and implemented. AM antenna loaded into small space of shark shape was designed by ferrite turn style antenna. For the FM and TDMB antenna, folded monopole antenna which helical is folded was applied. GPS antenna for achieving characteristics both bandwidth and gain improvement was designed microstrip patch that has air substrate and fractal structure. Receiving signal strengths by the measurement were presented for the AM, FM and TDMB antenna. AM signal strength was -65.7dBm, this strength is almost as same conventional pole antenna as -63.4dBm. It can be replaced conventional pole or glass antenna by the studied antenna. Signal strengths for FM and TDMB were -55.66 and -43.50dBm at center frequency, they are 5~10dB higher than conventional antenna. Measurements of bandwidth and gain for the GPS antenna showed 135 MHz under VSWR 2 : 1 and 4.31dBi, gains over GPS band were 3~5dB higher than ceramic patch antenna.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.2
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• pp.41-50
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• 2010

In this paper, a multi-band antenna with novel structure for mobile communications is designed and fabricated. The proposed antenna has the Multi-band antenna characteristics by two common-grounded slots with different size and angle. In order to reduce size and to enhance the gain of the antenna, a reflector is consisted of chokes on the three sides. It is optimized by using the CST Microwave Studio commercial software based on the FIA(Finite Integration Algorithm) and PBA(Perfect Boundary Approximation), and then the fabricating and measuring is practiced. As a result of measurement, the reflection coefficient is less than -11 dB(VSWR < 1.8) and the gain of antenna is more than 6dBi at 824~894MHz and 1885-2500MHz.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.2
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• pp.119-125
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• 2007

In this paper, a multi-band folded planar monopole internal antenna for mobile handset applications is proposed. The proposed antenna has multi-resonances, which is different from a conventional folded monopole antenna, and it provides a wide bandwidth at high frequency bands. The measured impedance bandwidth (VSWR < 3) is 180 MHz and 1880 MHz in lower and higher frequency bands, respectively. The proposed antenna can effectively cover most wireless communication bands including CDMA, GSM, GPS, DCS, PCS, and W-CDMA, WiBro and S-DMB.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.3
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• pp.101-110
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• 2007

This study has designed a circular polarization antenna for UHF bandwidth RFID reader. As a result of performance test of the antenna designed it is found that return loss (S11) is about -45.529dB at 914MHz, which is relatively small, and antenna gain is about 6.09dBi. It has also been confirmed that $50{\Omega}$ impedance matching is about $50.48{$\Omega}$ and it can be applied to every RFID reader. Therefore, the antenna is designed to have higher gain of circular polarization by improving reception, which is one of the most important parameters of RFID reader and is expected to be extensively used to recognize multi-tag in the distance.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.4
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• pp.80-85
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• 2012

In this paper, a new planar folded UHF band RFID reader antenna is suggested. For the antenna suggested in this paper, 4 PIFA (Planar Inverted F Antenna) micro-strip structures are adopted. The size is $50mm{\times}50mm{\times}6.2mm$. The gain of the antenna is 1.1 dBi, the VSWR is 1.2:1, and the efficiency is 63.3 %. The radiation pattern is designed as upper direction. Identification distance for the RFID tags is improved by minimizing hand effects with properly integrating 4 PIFAs.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.3
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• pp.78-86
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• 2013

A hybrid MIMO(Multi Input Multi Output) antenna which is operating both a monopole and a IFA(Inverted F Antenna) is designed. It's applied Vlade(Vertical lade) technique to reduce antenna space, and a diagonally fed MIMO antenna is designed on the bare board for the data communication. Return losses due to variables of antenna length are simulated for the design. Antenna for the hexa-frequency band of LTE700, CDMA, GSM, DCS, PCS and WCDMA is designed and implemented. This antenna is satisfied 3:1 VSWR over the whole design band by the measurement of return loss. And average gains and efficiencies were -3.67 ~ -2.53dBi and 42.06 ~ 55.84% for LTE700/CDMA/GSM frequency band, -3.27 ~ -1.21dBi and 47.08 ~ 75.6% for DCS/PCS/WCDMA frequency band. The isolation between 2 antenna that is one of important factors for the MIMO system was measured good performance as -8.14 ~ -25.77dB over the whole service band.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4773-4779
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• 2012

In this paper we propose two types of reconfigurable 3-D beam steering antenna for intelligent or smart antenna system. Proposed antennas are composed of triangular(structure1.) or circuler(structure2.) loop structure and bended dipole antenna structure. This antenna can steer beam pattern of 6 direction at xy-plane state (0, 1, 2) and xz-plane state (3, 4, 5) by 4 switch motion with one antenna element. Antenna structure1. is symmetric equilibrium structures based on feeding point. There is no grounding point. As a result, designed antenna's gain is similar to dipole antenna. Also, As unbalanced structure by using CPWG in the form of a semicircular, structure2. is enhanced directivity. The operation frequency of antenna are 2.5 GHz(Structure1.) and 2.55 GHz(Structure2.), maximum gain is 1.04 ~ 2.06 dBi(Structure1. : Omni-directional beam), 1.6 ~ 4 dBi(structure2. : Directional beam). The overall HPBW is about over $160^{\circ}$ in the both of the xy-plane and xz-plane at structure1. and over $125^{\circ}$ at structure2.

• 한국ITS학회:학술대회논문집
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• v.2006 no.10
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• pp.171-174
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• 2006

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.2
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• pp.42-49
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• 2014

A broadband antenna using a main and a sub antenna for the mobile communication terminal such as mobile phone and ITS terminal is designed. Two antennas are based on the hybrid antenna that is operating both a monopole and a IFA(Inverted F Antenna). It's applied the transmission line to connect both antennas. Sub antenna located in small space of the terminal allows space usability for the terminal design. Antenna for the hexa-frequency band of LTE700, CDMA, GSM, DCS, PCS and WCDMA is designed and implemented on the bare PC board that is same size of the mobile phone. This antenna was measured 3 : 1 VSWR over the whole design band. And average gains and efficiencies were-3.78 ~ -2.62dBi and 41.9 ~ 54.73% for LTE700/CDMA/GSM frequency band, -3.75 ~ -1.84dBi and 42.19 ~ 65.46% for DCS/PCS/WCDMA frequency band.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.2
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• pp.100-107
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• 2009

Velocity estimation is one of important issues for efficient system management in mobile cellular systems. In this paper, a modified velocity estimation scheme which works in Adaptive Antenna System (AAS) is proposed. The proposed scheme estimates user velocity based on moving distance information and sojourn time information. From numerical results, it is shown that the proposed scheme can estimate user velocity accurately with low cost.