• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.8
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• pp.880-885
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• 2010

In this paper, we propose a reconfigurable beam steering antenna using a dipole and a loop. The radiation patterns of the two antennas were cancelled or compensated, and head for the specific direction when a dipole and a loop antenna are combined at the reasonable ratio. The structure of the antenna is very simple and planar. By changing on/ off states of switches, the proposed antenna can steer the beam direction in the x-y plane. Simulation results confirmed the steering characteristic by using two imaginary switches. The proposed antenna can change the direction of the maximum gain in the x-y plane($0^{\circ}$, ${\pm}50^{\circ}$). The proposed antenna operates in 2.5~2.56 GHz(VSWR<2). It showed that peak gain of the antenna is 1.96~2.48 dBi and overall beam width of the reconfigurable antenna covers about $125^{\circ}$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.12
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• pp.1455-1461
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• 2008

We implemented a subminiature internal antenna that is around 1 cc volume for the mobile phone. The fundamental type of studied antenna is IFA(Inverted F Antenna), and this antenna is designed to be improved efficiency and gain due to minimum current cancellation by the avoidance of multiple bending pattern. For the implementation of multiple band, helix is applied to compensate for short antenna length for low frequency band, and a 3 dimensional pattern is used for high frequency band. We made two kinds of 3D structure antenna. One is a 1 cc volume antenna for GSM/DCS band on the bare board set, and the other is a 1.5 cc volume for the GSM/USPCS mobile phone set. Measurements showed good gain performance that average gain of two antenna on each band are $-3.46{\sim}-0.45\;dBi$ and $-4.80{\sim}-3.29\;dBi$ respectively.

• Publications of The Korean Astronomical Society
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• v.29 no.3
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• pp.53-58
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• 2014

We improved the antenna efficiency of the Taeduk Radio Astronomy Observatory (TRAO) 13.7-m radio telescope by adjusting the antenna panels based on digital photogrammetric measurements. First of all, we measured the surface accuracy of the main reflector of this antenna at three elevation angles of $35^{\circ}$, $45^{\circ}$, and $60^{\circ}$. We performed a total of four sets of the photogrammetric measurements and panel adjustments. When adjusting the panels, we positioned the antenna to the zenith and applied the measured data sets at the elevation of $45^{\circ}$. We found that the antenna surface accuracy has been improved by a factor of ~ 3 times after the final adjustment in comparison with the value before the adjustments. And we also found that the antenna surface accuracy tended to be slightly better at the elevation angles of $35^{\circ}$ and $60^{\circ}$ than that at the elevation angle of $45^{\circ}$. After the final panel adjustment, the aperture and beam efficiencies of the telescope have has been improved from 35% to 44%, and from 41% to 51%, respectively.

• Journal of the Korean Institute of Telematics and Electronics
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• v.11 no.4
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• pp.9-16
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• 1974

The low channels with frequency range of 54~88MHz and the high channels with frequency range if 174~216 MHz are in use for TV broadcasting in Korea. Since the ratio of the highest frequency to the lowest frequency is 4 to 1, only a logarithmic periodic antenna cou1d cover such an wide frequency range. But, this log-periodic antenna should be big in size. Studies have been done on an antenna of small size with reasonable gain which combines through a channel filter a LPD antenna if low channel with boom length of 2m and a LPD antenna of high channel with boom length of 1.8m. The whole antenna is connected to feeder line through a talun. Experiment shows that the gain of low and high channels is 7 dB and 9 dB respectively, which are lower than theoretical values br nomore than ldB. The difference seemed to come from slight impedance mismatches between antennas and feeder lines, loss in the filter and measurement errors.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.313-316
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• 2005

In this paper, an active antenna for terrestrial DMB(Digital Multimedia Broadcasting) repeater is designed. This active antenna is consist of receiving antenna and LNA(Low Noise Amplifier), A receiving antenna fed by using a microstrip line and radiation part is designed with rectangular spiral structure. An receiving antenna with frequency range of 162$\sim$212MHz, gain of -10dBi and LNA with gain of 20dBi, noise figure of 2.2 at frequency range for T-DMB are achieved.

• Journal of electromagnetic engineering and science
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• v.10 no.3
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• pp.175-178
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• 2010

In this paper, a millimeter-wave multi-beam antenna is studied by rotating the antipodal linear tapered slot antenna(ALTSA) with respect to a center is successfully designed. In order to lowering the SLL and enhancing the isolation between the ALTSA elements, a row of metallic via is inserted between the ALTSAs. A 9 beams antenna is designed and experimented at Ka band. The measured and simulated results agree well with each other. The antenna can provide horizontal wide angle coverage up to ${\pm}62^{\circ}$. The gain of each beam can achieve about 12.5 dB. The mutual coupling between ports is all below 20 dB.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.1
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• pp.24-28
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• 2010

This paper is presented on the antenna design for notepc platform. We present the antenna with combination of electric-magnetic radiator for dual-band Wireless Local Area Network (WLAN) service and a High Speed Downlink Packet Access (HSDPA) service. Due to the limited antenna space in notepc platform, the antennas for various wireless communication service should be located at a very small area. In this paper, the magnetic-type radiator works for high frequency band (1.7 - 2.1 GHz) application and the electric-type radiator works for low frequency band (820 - 960 MHz) application. This combination produces wide-band characteristics in the high frequency band. Simulation and experimental results of input impedance and gain characteristics of the proposed antenna are presented. There are good agreements between the simulated and measured S11 and gain values.

• 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.

• Journal of electromagnetic engineering and science
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• v.15 no.4
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• pp.213-218
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• 2015

A novel body-worn spiral monopole antenna is presented. The antenna consists of a ground plane and a spiral monopole. The antenna was designed for Ear-to-Ear (E2E) communication between In-the-Ear (ITE) hearing instruments at 2.45 GHz and has been simulated, prototyped, and measured. The antenna yielded a measured and simulated E2E path gain at 2.45 GHz of -82.1 dB and -85.9 dB, respectively. The radiation pattern of the antenna when mounted in the ear is presented and discussed.

• Journal of electromagnetic engineering and science
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• v.15 no.2
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• pp.111-114
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• 2015

In this paper, we have proposed dual-band Phi-shaped slot gap filler antenna for satellite internet service applications. Some properties of the antenna such as return loss, radiation pattern, and gain have been simulated and measured. The proposed antenna has a Phi-shaped slot on the circular patch and is fabricated on the TLX-9 substrate. The radius of the circular patch is 25 mm, and it has a coaxial feeding structure. The dual-band Phi-shaped slot gap filler antenna has high-gain, small-size, simple-structure, and good radiation patterns at each band. The operating frequency band can be tuned by adjusting the length AL and FL of the Phi-shaped slot.